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NI PXIe-5450 User Manual

1. Prefilter Gain Overflow Any time the following condition is not true for the I or Q data stream an overflow occurs when prefilter gain is applied 1 lt User Data x Prefilter Gain lt 1 If an overflow occurs the data is clipped and NI FGEN returns an error To prevent data clipping attenuate the waveform data or reduce the prefilter gain Tip To disable error reporting caused by OSP overflows use the OSP Overflow Error Reporting property or the NIFGEN_ATTR_OSP_OVERFLOW_ERROR_REPORTING attribute NI PXle 5450 User Manual Prefilter Offset Prefilter offset can add offset to the I and Q stream during signal generation Change the I and Q prefilter offsets independently by setting the Pre Filter Offset I and Pre Filter Offset Q properties or the NIFGEN_ATTR_OSP_PRE_FILTER_OFFSET_I and NIFGEN ATTR OSP PRE FILTER OFFSET O attributes The offset can 2 22 ni com Chapter 2 NI 5450 Overview range from negative full scale 1 to positive full scale 1 Any time the prefilter offset changes the OSP block ignores all overflows for the next VO samples If an overflow occurs during these samples the data is clipped but an error is not returned Prefilter Offset Overflow Any time the following condition is not true for the I or Q data stream an overflow occurs when prefilter offset is applied 1 lt User Data x Pre Filter Gain Pre
2. Without Interpolation With Interpolation After Analog Filtering yl Note The allowable range of interpolation factors is dependent on the NI signal generator being used Using two times interpolation filtering with a DAC effective sample rate of 2f eliminates images well and generates a good signal However increasing the interpolation filter to 4 further improves the output signal NI PXle 5450 User Manual 5 16 ni com Chapter 5 Signal Generation Fundamentals The following figure shows a signal image with four times interpolation and the effective DAC sample rate at 4f The images are shifted up to 4f and well above the cutoff frequency of Analog Filter 3 This configuration eliminates the spectral images and has a filter that is maximally flat within the passband This configuration approaches an ideal design in digitally generating spectrally pure waveforms Signal 0 5f f 2f 3f af To generate the most spectrally pure signals using the digital filter you should use the highest interpolation factor that you can National Instruments Corporation 5 17 NI PXle 5450 User Manual Technical Support and Professional Services Visit the following sections of the award winning National Instruments Web site at ni com for technical support and professional services National Instruments Corporation Support Technical support at ni com support includes the following resources Self He
3. Reference Clock The Reference clock is the actual clock that is configured for the signal generator phase locked loop circuit to use as a reference You configure a Reference clock as a PLL Reference clock source for the signal to be available for exporting The Reference clock can be routed to the PFI lt 0 1 gt front panel SMB connectors the CLK OUT front panel SMA connector or the PXI_Trig lt 0 6 gt lines on the PXI trigger bus yl Note NI FGEN allows values for Reference clock frequency on the NI 5450 from 1 to 100 MHz in 1 MHz increments 102 to 200 MHz in 2 MHz increments and 204 to 400 MHz in 4 MHz increments Destination Options The following sections define the destinations for exported clocks PFI lt 0 1 gt The Sample clock when K 22 the Sample clock timebase when M 22 and the Reference clock can be exported to the PFI 0 and PFI 1 SMB connectors on the front panel to synchronize external devices You must configure the device to export the desired clock to the PFI SMB connectors CLK OUT The Sample clock the Sample clock timebase and the Reference clock can be exported to the CLK OUT SMA connectors on the front panel to synchronize external devices You must configure the device to export the desired clock to the CLK OUT SMA connector National Instruments Corporation 2 43 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview PXI_Trig lt 0 6 gt Sample clock when K 22 the Sample clock time
4. Enabling simulation allows you to verify that you have correctly configured the device For example if a parameter is set to an invalid value for the device NI FGEN returns the same error it would for a real device While simulation is useful for verifying your configuration there are some areas where simulation is not sufficient to verify that your configuration is correct For example no errors will be returned for configurations that involve or depend upon external signals such as configuring an external Sample clock or routing signals Also the amount of time a generation takes to complete will be ignored in simulation mode a finite generation will finish immediately after it is initiated regardless of how much data is downloaded and how fast it is generated 4 32 ni com Chapter 4 Programming LabVIEW Example In LabVIEW simulation is enabled with the Option String parameter of the niFgen Initialize With Options VI Enable simulation Simulate 1 and specify the device you want to simulate with the option string input The following example enables simulation of the NI PCI 5421 with 256 MB of onboard memory Simulate 1 DriverSetup Model 5421 BoardType PCL MemorySize 268435456 Resource Name niFgen Initialize With Options vi For more information refer to the niFgen Initialize With Options VI C Example In LabWindows CVI simulation is enabled with the niFgen_InitWithOptions function Enable sim
5. Script Output Maximum Number of Script Triggers Maximum Number of Markers Streaming Yes Output Characteristics Output Voltage at load equal to source impedance up to 5 V up to 5 V up to 6 V up to 6 V up to 6 V up to 6 V up to 1 V up to 1 V Offset at maximum gain 5 Vox 25 Vix 0 5 V OV Output Impedance 50 Q 75 Q 50 Q 75 Q 50 Q 75 Q 50 Q 75 Q 50 Q 75 Q 50 Q 75 Q 50 Q 75 Q 50 Q National Instruments Corporation NI PXle 5450 User Manual NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Analog Path Main Main Main Main Main Main Main Direct Fixed Fixed Fixed Direct Direct Direct Direct Low Gain Low Gain Low Gain Fixed Fixed Fixed Fixed Fixed Fixed Low Gain Low Gain Low Gain High Gain High Gain High Gain Fixed Fixed Fixed High Gain High Gain High Gain Analog Yes Yes No Yes Yes Yes Yes Filter Option Flatness Yes Yes Yes Correction for Sine Waveforms Flatness Yes Correction for Arbitrary Waveforms Digital Yes Yes Yes Yes Yes Yes Filter Option Digital 2 or 4 2 or 4 2 4 or 8 2 4 or 8 2 4 or 8 2 4 or 8 Filter automatic automatic maximum maximum maximum maximum Interpo forStandard forStandard of of of of lation Functio
6. This topic assumes that you are using Visual C C to manage your code development and that you are familiar with the ADE To develop an NI FGEN application in Visual C C follow these general steps 1 Open an existing or new Visual C C project 2 Create source files c C source code or cpp C source code and add them to the project Make sure that you include the NI FGEN header file ni FGEN h in your source code files as follows include niFGEN h 3 Specify the directory that contains the NI FGEN header file under the PreprocessorsAdditional include directories settings in your National Instruments Corporation 4 7 NI PXle 5450 User Manual Chapter 4 Programming NI PXle 5450 User Manual compiler for Visual C 6 0 these files are under Project Settings C C For the location of the NI FGEN header files refer to the NI FGEN Instrument Driver Readme 4 Add the NI FGEN import library niFGEN 1ib to the project under Link General Object Library Modules For the location of the NI FGEN import library files refer to the NJ FGEN Instrument Driver Readme 5 Add NI FGEN function calls to your application 6 Build your application NI FGEN Example Programs for Visual C C To locate the example programs installed with NI FGEN refer to the NI FGEN Instrument Driver Readme Special Considerations String Passing To pass strings pass a pointer to the first element of the character arr
7. e MAX returns an error message if you run a self test on your device after it exceeds the thermal shutdown temperature To re enable your device after thermal shutdown use one of the following methods e Power down the computer or chassis that contains the signal generator or e Call the niFgen Reset Device VI or the niFgen ResetDevice function or perform a device reset in MAX For more information about resetting a device in MAX select Help Help Topics NI DAQmx MAX Help for NI DAQmx within MAX Review the guidelines in the Maintain Forced Air Cooling Note to Users document that shipped with the product and make any necessary adjustments to ensure that the signal generator cools effectively The thermal shutdown error continues to be reported until the device is successfully reset NI PXle 5450 User Manual 2 10 ni com Chapter 2 NI 5450 Overview Theory of Operation Block Diagram This topic contains information about the NI 5450 top level block diagram and descriptions of the individual blocks Synchronization and Memory Core Onboard Memory waveform PCle 4 Bus Interface PCle Bus PXI_CLK10 Digital Anal eres Generation 1 Ji DAC 0 nalog Engine H Gain 0 Output Path with Lowpass AA A Filters 0 e CHO Sample Onboard Clock 0 Signal Processing T e JCH 1
8. 4 samples 4 samples 4 samples 4 samples 1 sample 2 samples Quantum National Instruments Corporation 1 3 NI PXle 5450 User Manual NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Minimum Waveform Write Size 4 samples 4 samples 4 samples 4 samples 4 samples 4 samples Maximum Waveform Write Size 4M 16M 128M samples 4M 16M 128 M 256 M samples 4M 16M 128 M 256 M samples 16 M 128 M 256 M samples 16 M 128 M 256 M samples 67 M 108 M 352 M samples Maximum Number of Waveforms 2 097 151 2 097 151 2 097 151 2 097 151 2 097 151 2 097 151 Streaming Yes Onboard Signal Processing Yes Arbitrary Se quence Output Minimum Sequence Length Maximum Sequence Length 16 777 205 16 777 205 16 777 205 16 777 205 16 777 205 16 777 205 Maximum Loop Count 16 777 215 16 777 215 16 777 215 16 777 215 16 777 215 16 777 215 Maximum Number of Sequences 2 097 151t 2 097 151t 2 097 151t 2 097 151 2 097 151t 2 097 151 NI PXle 5450 User Manual ni com NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Streaming Yes Yes Yes Yes Yes Onboard Signal Processing Yes Yes Yes
9. Assumptions Internal Sample clock High Resolution clock mode Desired sample rate ranges do not include the first point a desired sample rate of 50 MS s yields 8x total interpolation If your interpolated sample rate falls within an undesirable band you can use the Modulation Toolkit to provide fractional resampling that will adjust the sample rate to achieve better image rejection Calculated from sinc response and typical filter rejection for the NI 5450 Refer to the NI 5450 specifications for more information about the expected performance of the NI 5450 NI PXle 5450 User Manual ni com Chapter 2 NI 5450 Overview Clock Source and Frequency The NI 5450 has a Sample clock rate of 12 2 kHz to 400 MHz The timing of the device is very flexible and you have multiple choices for deriving the Sample clock There are modes for deriving the Sample clock from the internal Sample clock timebase as well as modes to provide external clocks You also have several choices for providing the frequency reference for the onboard phase locked loop Reference Clock External Sample Clock Sample Clock Timebase M p gt Divide M CLK OUT Divide K CHO Channel Sample Clock High PLL gt Resolution with Phase Oscillator Adjust PXI_CLK10 J Delay Divide N CH1 Channel Sample Clock EE Sample Clock None Exter
10. Generated Continuously End of Waveform The waveform pattern you define in the sequence list generates only once When a Start trigger is received generation begins at the first segment and continues through the last segment after which the waveform generation halts You can determine the DC value at which waveform generation ends by configuring the last point in the final segment as the desired DC value or you can add an extra segment filled with the same DC value Start Trigger Y Last Sample of Last Segment A Generated Continuously End of All Segments NI PXle 5450 User Manual 2 76 ni com Chapter 2 NI 5450 Overview Continuous Trigger Mode The waveform you downloaded generates continuously after receiving one Start trigger All Start triggers after the first Start trigger are ignored The following table provides more information about waveform generation behavior in Arbitrary Waveform and Arbitrary Sequence output modes Output Mode Trigger Behavior Arbitrary Waveform Mode The waveform you downloaded generates continuously after receiving one Start trigger All Start triggers after the first Start trigger are ignored Start Trigger y 4 K iy yva Vse se d 1 1 Waveform Repeats ttt tt Continuously End of Waveform 1 p E 1 H 1 i 1 k 1 1 Arbitrary Sequence Mode The waveform pattern you define in the sequence list generates continuously by cont
11. VO Freguency Rate Shift Pre Filter Pre Filter Filtering Digital Gain Q Offset Q id and Interpolation Q gt gt Gain Q gt J l Programmable VO Pulse Shaping Gain amp Offset Control and Interpolation National Instruments Corporation The OSP block includes the following components Prefilter Gain and Prefilter Offset FIR filters Filtering and Interpolation Writing VO Data 2 21 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview VO Rate The I Q rate component holds off the data from the output engine so that a new sample is only returned once every Total_OSP_Interpolation Sample clocks 3 Note The Total_OSP_Interpolation is the amount of interpolation applied within the Filtering and Interpolation component and does not include the DAC interpolation Prefilter Gain Prefilter gain can change the gain of the I and Q stream during signal generation You can change the I and Q prefilter gains independently by setting the Pre Filter Gain I and Pre Filter Gain Q properties or the NIFGEN_ATTR_OSP_PRE_FILTER_GAIN_I and NIFGEN_ATTR_OSP_PRE_FILTER_GAIN_Q attributes The gain can range from 16 0 to 16 0 unitless Any time the prefilter gain changes the OSP block ignores all overflows for the next I Q samples If an overflow occurs during these samples the data is clipped but an error is not returned The prefilter gain can be used to attenuate the I Q data to eliminate overflows in later stages of the OSP block
12. waveform 6 Call the niFgen WriteWaveform function to write a new block of waveform data to the streaming waveform in onboard memory Repeat the process of monitoring the available memory and writing waveform data in blocks as free space becomes available Configuring Your Application for Direct DMA You can achieve high rates of data transfer to the onboard memory by configuring your device for Direct DMA Direct DMA establishes a direct connection between the signal generator onboard memory and a specialized waveform data source The dire following instructions are a guide for configuring your application for ct DMA LabVIEW Example 1 National Instruments Corporation Enable the signal generator for direct DMA writes by setting the Direct DMA Enabled property Once enabled NI FGEN monitors and reports any issues with the direct DMA transfer Identify the waveform data source and set the Direct DMA Window Address property to the address provided by your direct DMA compatible data source Set the Direct DMA Window Size property to the size of the memory window provided by your direct DMA compatible data source Use the niFgen Write Waveform I16 Direct DMA VI to write blocks of data to the signal generator For each block of data written to the signal generator you provide the address of the direct DMA window instead of an array of samples residing in host memory NI FGEN detects when the address is within the d
13. Digital se J DAC 1 p _ Analog Gain 1 Output Path with Lowpass Filters 1 Sample we CH1 Clock 1 lt _ _ e CLK IN e Clocking Exported vv Clocks se use EE and Event a rigger Signal 4 pe PFIO PXle Chassis PXI_Trig lt 0 7 gt gt Control Routing Matrix lt t e PFI1 PXI Trigger Bus IHS CLK OUT National Instruments Corporation The following list describes the individual blocks Onboard Memory stores the waveform data and generation instructions that you load into the device Clocking allows you to create your Sample clock and Reference clock The Waveform Generation Engine retrieves the waveform data and instructions from the Onboard Memory using the Sample clock The Waveform Generation Engine also uses this clock to retrieve triggers from Trigger and Event Control The output from the Waveform Generation Engine is sent to the DAC device after any digital gain or onboard signal processing is applied The waveform data is sent from the DAC to the Analog Output path where the waveform data is filtered The Routing Matrix allows flexible routing of the PXI Trigger lines and the external PFI lines 2 11 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Hardware State Diagram The following diagram shows the hardware states of the si
14. f 2f 3f Af The images shown in the previous figure degrade the spectral purity of the signal creating the need to filter these images out of the signal To create quality signals all NI signal generators can lowpass filter the generated signal A lowpass filter can smooth the raw DAC output The filter removes high frequency aliased components that are introduced through the digital generation of the signal You can implement the lowpass filter through both analog and digital filters Designing an analog filter that rejects the images and yet gets maximum output bandwidth 0 to 0 43f is difficult and is represented by the curve Analog Filter 1 in the following figure Analog Filter 2 represents a more practical filter This filter is not as aggressive as Analog Filter 1 Analog Filter 2 does not filter out the images near f but it does reject all the others Analog filters have trade offs between the roll off of the attenuation after the 3 dB point and the flatness of the attenuation before the 3 dB point Another aspect of the analog filter is group delay the amount of time needed for a signal having finite time duration such as a pulse to pass through the analog filter Ideally in an analog filter with linear group delay all frequencies present in the signal should have the same time delay so that the signal is not distorted NI PXle 5450 User Manual 5 14 ni com Chapter 5 Signal Generation Fundamentals The third
15. sequences and scripts from the signal generator memory 3 Call one of the niFgen Create Waveform functions niFgen CreateWaveformF64 niFgen_CreateWaveformI16 niFgen_CreateWaveformComplexF64 niFgen_CreateWaveformFromFileI16 or niFgen_CreateWaveformFromFileHws The function you choose creates a waveform the size and type of the data you choose National Instruments Corporation 4 15 NI PXle 5450 User Manual Chapter 4 Programming NI PXle 5450 User Manual 4 Call the niFgen_CreateArbSequence function or the niFgen_CreateAdvancedArbSequence function 5 Call the niFgen ConfigureArbSeguence function to configure the gain and offset of the waveform Configure Frequency List Mode You can use Frequency List mode to generate a standard function using a list of frequencies you define LabVIEW Example The procedure below provides the basic steps required to configure Frequency List mode For an example of the use of Frequency List mode in LabVIEW refer to the Fgen Sweep Generator vi example 1 Call the niFgen Configure Output Mode VI with Output Mode set to Frequency List 2 Optional Call the niFgen Clear Frequency List VI to remove any previously created frequency lists from the signal generator memory 3 Call the niFgen Create Frequency List VI to set the function type the frequency list and the duration of each step in the list 4 Call the niFgen Configure Frequency List VI to select the active frequency list
16. 1 1 2 1 4 1 6 1 8 2 Frequency NI PXle 5450 User Manual 2 26 ni com Chapter 2 NI 5450 Overview Filtering and Interpolation The filtering and interpolation stage of the OSP block increases the effective sample rate of the signal generator while protecting the frequency spectrum of the interpolated data from images This protection occurs when the data passes through a lowpass filter after zero stuffing The frequency response of the low pass filter can be changed with the Filter Type property or the NIFGEN_ATTR_OSP_FIR_FILTER_TYPE attribute Low Pass Input Data Output Data Filter Low Sample Rate High Sample Rate Writing VO Data On multichannel devices I Q data can either be written to individual channels for example designating one channel for I data and one channel for Q data or to both channels of the device at once when following the multichannel waveform allocation guidelines Basic Onboard Signal Processing Properties The following properties must be configured before you can use the OSP block e OSP Mode e OSP Enabled e Data Processing Mode e IQ Rate e Frequency Shift e FIR Filter Type OSP Mode The OSP Mode property or the NIFGEN_ATTR_OSP_MODE attribute specifies the generation mode implemented by the OSP block The OSP block can operate in IF and Baseband modes On the NI 5450 the default OSP mode is Baseband generation National Instruments Corporation 2
17. 27 NI PXle 5450 User Manual Chapter 2 3 NI 5450 Overview In baseband mode I Q data is filtered interpolated and scaled in the device OSP The device generates I data at the CH 0 and CH 0 differential output terminals and Q data on the CH 1 and CH 1 differential output terminals OSP Enabled The OSP Enabled property or the NIFGEN_ATTR_OSP_ENABLED attribute activates the functionality of the OSP block To use any of the features in the OSP block you must enable onboard signal processing by setting this property or attribute Data Processing Mode Data Processing mode determines whether the OSP block uses only the I signal path to generate waveforms or uses the I and Q signal paths to generate complex waveforms If the waveform data is configured for real data points by setting the Data Processing Mode property or the NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE attribute only the I signal path is used If the Data Processing Mode property is set to Complex or the NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE attribute is set to NIFGEN_VAL_OSP_COMPLEX both the I and Q signal paths are used Complex waveform data should be downloaded to the signal generator using the niFgen Write Waveform Complex VI or the niFgen_WriteWaveformComplex f64 function 10 Rate The IQ Rate property or the NIFGEN_ATTR_OSP_IQ_RATE attribute defines the rate at which data is processed by the OSP block If the waveform data is configured
18. 4 208 bytes Size in memory 4 208 coerced up to the next multiple of 128 4 224 bytes 3 The memory size required to generate a waveform using Arbitrary Sequence mode and Continuous trigger mode with 500 segments in a sequence list is determined by the following formula Size in Bytes 208 64 x 500 32 208 bytes Size in memory 32 208 coerced up to the next multiple of 128 32 256 bytes 4 The memory size required to generate a waveform using Arbitrary Sequence mode and Single trigger mode with 1 003 segments in a sequence list is determined by the following formula Size in Bytes 80 64 x 1 003 64 272 bytes Size in memory 64 272 coerced up to the next multiple of 128 64 284 bytes 2 48 ni com Chapter 2 NI 5450 Overview The memory size required to generate a waveform using Arbitrary Sequence mode and Burst trigger mode with 2345 segments in a sequence list is determined by the following formula Size in Bytes 160 128 x 2 345 300 320 bytes Size in memory 300 320 coerced up to the next multiple of 128 300 416 bytes Total Memory Size The following examples show how to calculate total memory for an application The examples use each of the four trigger modes for the Arbitrary Sequence mode and use varying numbers of waveforms waveform sizes and number of segments in the sequences 3 Note The following examples only consider the memory used for instructions for one sequence It is pos
19. B EO EE RE cdeasiie 2 74 MEE EE EE EE seed SR 2 74 Software THIS SEL AR EE OE EE 2 74 Trigger SourceS OE RE RS AE EE KO EE 2 74 Tigger MOdeS RE EE N ER EE 2 75 Single Trigger Mode EE a chaste ESEG be N Gee gee see bg bee 2 76 Continuous Trigger Mode esse se ee ek ee Ge ee ee ee ee ee 2 77 Stepped Trigger Mode esse see ee ee Ge ee Se Re de Re ek ee 2 78 Burst Tigger Mode isi sek se ER ees eg Gee ES de ee eg Re Ee ee EED Eg Ee 2 79 Trigger TIMIN E Es ee RE Ee sk en xs ER EEEE Oe GE seed ide Seg SERE bes Pe ge kg R ewe d ee Sevens 2 80 Filtering Effects isnon a RE RED 2 80 Dita ESRA RR OE EE OER OE OR RR EE 2 81 National Instruments Corporation ix NI PXle 5450 User Manual Contents AE RE EE EE EE lead EE OE OE AE 2 81 Event Output Behaviors sesse ses see ee ee ee ee ee ke ee ee ee 2 81 EVent Status 4 04 RE RR EE ET ENS 2 81 EG GAAR EE ER acs 2 83 Markers as Trigger Outputs iese sesse se se ee ee ee Re ke ee ee 2 84 BEWE RR EE ER IE HE EE EE 2 84 Data Markers as Trigger Outputs occ se ee ee ee ke ke 2 85 Event Delay sis ER ER EE 2 85 Exporting Sipmals scc scescc cbsscscvecs ER EE EE EE OG 2 86 PAS UIER RE EE OE AE beara 2 88 RYE EE EE EE EE EE EE RE ER 2 89 Metale EE OE EE ER AE EE EE teeterdues ets 2 89 Calibration EE RE ER EE OE EO N aad 2 89 Nes oe RE ER EE EE RE 2 89 Chapter 3 Integration and System Considerations Environment onces a EE RE RE EE EN ET 3 1 PXI PXI Express Chassis Cooling rssi see see see ee
20. Configure the Sample clock source with niFgen Configure Sample Clock Source VI or the niFgen_ConfigureSampleClockSource function The Sample clock uses the internal clock by default External Sample Clock Timebase Input The CLK IN connector also can receive an external Sample clock timebase Refer to the device specifications for the allowable external Sample clock timebase frequencies and signal characteristics Configure the Sample clock timebase source with the Sample Clock Timebase Source and Sample Clock Timebase Rate properties or the NIFGEN_ATTR_SAMPLE_CLOCK_TIMEBASE_SOURCE and NIFGEN_ATTR_SAMPLE_CLOCK_TIMEBASE_RATE attributes The device uses the internal sample clock timebase by default 2 6 ni com Chapter 2 NI 5450 Overview CLK OUT Connector The CLK OUT connector is typically used as an output terminal to provide a clock signal that can be shared by other devices The CLK OUT connector is designed to allow the NI 5450 to generate high speed clock signals with very low jitter As an output the CLK OUT line routes a signal out from the following sources e PLL Reference clock source e Sample Clock Out with K where K is an integer used to divide the Sample clock e Sample clock timebase with M where M is an integer used to divide the Sample clock timebase frequency Refer to the device specifications for information about the signal characteristics for the CLK OUT connector P
21. Enable CH 0 Onboard Signal Processing oops EA Block Filter EA 16 Output Enable J Direct 50 Q Relay Path Output Enable Output Enable Relay The Direct path provides the output of the main DAC to the CH 0 connectors with the fewest electronic components in the path There are no programmable amplifiers and there is no method for adding DC offset to the waveform The Direct path can generate a maximum of 1 0 V pk pk at the Lowpass Filter Gain DAC 0 dB to 3 dB National Instruments Corporation 2 15 NI PXle 5450 User Manual Chapter 2 3 NI 5450 Overview CH 0 output into matched load impedance The maximum gain setting for an Analog Output path configured to the Direct path is 0 5 gain is a unitless value Attenuation The main DAC output can be fine tuned for attenuation which provides 0 to 3 dB of the Analog Output path signal attenuation Attenuating the DAC output signal allows you to vary the signal amplitude while maintaining the dynamic range of the DAC You do not lose any bits from the digital representation of the signal and you do not sacrifice dynamic range as you would if you control amplitude by using smaller data ranges of the DAC The main DAC also provides the fine resolution for the attenuation settings Fine tuning of the main DAC attenuation is performed by the gain DAC Adjust the gain DAC using the Gain DAC Value property or the NI
22. Filter Offset lt 1 If an overflow occurs the data is clipped and NI FGEN returns an error To prevent data clipping reduce the prefilter gain attenuate the waveform data or reduce the prefilter offset 9 Tip To disable error reporting caused by OSP overflows use the OSP Overflow Error Reporting property or the NIFGEN ATTR OSP OVERFLOW ERROR REPORTING attribute FIR Filter Types There are a number of built in low pass pulse shaping filters available in NI FGEN Because the coefficients are scaled for unity gain the filters may overflow if transients such as step response are presented at the input of the filter Use the Filter Type property or the NIFGEN_ATTR_OSP_FIR_FILTER_TYPE attribute to set the FIR filter type The following filters are currently available e Flat e Raised Cosine e Root Raised Cosine yl Note Enabling filters in the OSP will add a constant group delay to your signal Digital Filter Overflow FIR filters may overflow If an overflow occurs data is clipped and NI FGEN returns an error Digital filter overflows are caused by transients Transients can occur as an abrupt jump at the beginning of a waveform or they may be present in the data you supply NI FGEN ignores overflows that are caused by transients at the beginning of a waveform You can choose to ignore overflow errors caused by transients present in your data with the OSP Overflow Error Reporting property or the NIFGEN_ATT
23. Freguencyff 20 MHz 40 MHz 20 MHz 43 MHz 80 MHz 43 MHz 43 MHz Square Square Square Square Square Square Square 20 MHz 40 MHz 5 MHz 25 MHz 100 MHz 25 MHz 25 MHz User User Other Other Other User User Defined Defined 1 MHz 5 MHz 10 MHz Defined Defined 20 MHz 40 MHz 43 MHz 43 MHz Other Other Other Other 1 MHz 5 MHz 5 MHz 5 MHz SYNC Duty 20 to 20 to Cycle 80 for 80 for square 50 square 50 for all other for all other User 16 384 16 384 Variable Variable Variable 16 384 32 768 Defined samples samples samples samples Waveform Size NI PXle 5450 User Manual 1 2 ni com NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Frequency List Output Maximum 9 999 lists 9 999 lists 9 999 lists 9 999 lists Number of Lists Maximum 58 253 s 58 253 s 932 066 s 932 066 s List Length Maximum 21s 21s 21s 21s Step Duration Minimum ls Is ls ls List Length Minimum 1 28 us 1 28 us 1 28 us 1 28 us Step Duration Step 80 ns 80 ns 80 ns 80 ns Duration Quantum Arbitrary Waveform Output Write 64 samples 64samples 64samples 64samples 64samples 64 samples 1 sample 1 sample Quantum or or or or or or 32 complex 32 complex 32 complex 32 complex 32 complex 32 complex samples samples samples samples samples samples Waveform
24. Generator ACCESS ACTIVE CLK OUT PFIO NI PXle 5450 User Manual 2 2 ni com Chapter 2 NI 5450 Overview The CLK IN SMA connector accepts an external clock that can be used as a Reference clock a Sample clock or a Sample clock timebase The CLK OUT SMA connector provides a clock signal that can be shared by other devices The PFI 0 and PFI 1 SMB connectors are bidirectional connections that can accept a trigger from an external source and can start or step through waveform generation or route signals from several clock event and trigger sources The CH 0 I SMA connector provides differential waveform output for channel 0 The CH 0 I SMA connector provides complementary differential waveform output for channel 0 The CH 1 Q SMA connector provides differential waveform output for channel 1 The CH 1 0 SMA connector provides complementary differential waveform output for channel 0 National Instruments Corporation 2 3 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Differential Channel Connectors The CH 0 and CH 1 connectors are the analog waveform output terminals These connectors provide differential waveform output they cannot be used for single ended operation The connectors must terminate into balanced loads The maximum output levels from these connectors depend on the type of load termination For exampl
25. Initiate Generation step transitions the device from the Committed state to the Generation state Once this transition has been made the device is able to begin generating waveforms LabVIEW Example Call the niFgen Initiate Generation VI to transition the device to the Generation state C Example Call the niFgen_InitiateGeneration function to transition the device to the Generation state The abort generation step aborts any signal generation that was initiated in the initiate generation step When you abort generation you can choose to either abort to ground or abort to a known voltage not available in Standard Function or Frequency List output modes Abort to Ground All operation modes can abort to ground To abort to ground you must disable the output enable relay to remove the DC voltage from the output LabVIEW Example To abort generation to ground complete the following steps 1 Call the niFgen Output Enable VI to with Output Enable set to FALSE to disable the analog output and remove any DC voltage on the analog output 2 Call the niFgen Abort Generation VI to stop the waveform generation National Instruments Corporation 4 19 NI PXle 5450 User Manual Chapter 4 Programming C Example 1 Call the niFgen ConfigureOutputEnabled function with the enabled parameter set to VI_FALSE to disable the analog output and to remove any DC voltage on the analog output Call the niFgen AbortGeneration function t
26. MHz Reference clock signal provided by the PXI bus PXI_CLK10 Note Refer to the device specifications for information about available signal levels on the CLK IN front panel connector NI PXle 5450 User Manual 2 38 ni com Chapter 2 NI 5450 Overview External Sample Clock Sources The NI 5450 can accept an external clock to directly drive the Sample clock When using an external Sample clock the frequency stability and accuracy of the Sample clock is determined by the provided external Sample clock The following figure shows possible Sample Clock paths Sample Clock 7 Timebase M Divide M Lal CLK OUT Divide K External Sample Clock CLK IN CHO Channel Sample Clock PLL W Delay jwith Phase Divide N CH1 Adjust eee Channel Sample Clock loc Delay Timebase You can set the clock source by calling the niFgen Configure Sample Clock Source VI or the niFgen ConfigureSampleClockSource function You can multiply the clock by an integer W or 1 W by calling the External Sample Clock Multiplier property or the NIFGEN_ATTR_EXTERNAL SAMPLE CLOCK MULTIPLIER attribute When using an external Sample clock you should configure the Sample clock rate by calling the niFgen Set Sample Rate VI or the niFgen_ConfigureSampleRate function Note Refer to the device specifications for the allowable voltages signal types and clocks
27. Marker event by setting the NIFGEN_ATTR_ARB_MARKER_POSITION attribute 2 Export the marker event by calling the niFgen ExportSignal function and setting the signal parameter to NIFGEN VAL MARKER EVENT 4 26 ni com Chapter 4 Programming Creating a Marker Event in Arbitrary Sequence Mode You can specify a marker and its location by setting an offset location value in number of samples from the start of the waveform If the offset is out of range of the number of samples in that segment NI FGEN returns an error LabVIEW Example 1 Call the niFgen Create Advanced Arb Sequence VI and set Marker Location Array to the location at which you would like the marker to generate 2 Export the marker event by calling the niFgen Export Signal VI and setting Signal to NIFGEN VAL MARKER EVENT C Example 1 Call the nifgen_CreateAdvancedArbSequence function and set the markerLocationArray parameter to the location at which you would like the marker to generate 2 Export the marker event by calling the niFgen ExportSignal function and setting the signal parameter to 5 NIFGEN VAL MARKER EVENT Creating a Marker Event in Script Mode You can specify a marker and its location by setting an offset location value in number of samples from the start of the waveform If the offset is out of range of the number of samples in that segment NI FGEN returns an error In Script mo
28. PXI trigger lines SYNC OUT PFI 0 and PFI 1 Data Marker Events NI PXle 5450 User Manual The Data Marker events allow you to export any one of the 16 waveform data bits to any valid destination on the device Up to four of the 16 waveform data bits can be exported at one time The level of a Data Marker event changes at the time that a specific data bit toggles in the waveform data If the waveform data bit toggles multiple times in a segment the Data Marker event level changes each time When the data bit level is high the Data Marker event level is high You can invert this relationship by setting the Data Marker Event Level Polarity property or the NIFGEN_ATTR_DATA_MARKER_EVENT_LEVEL_POLARITY attribute 2 84 ni com Chapter 2 NI 5450 Overview The following figure shows the exported data marker event shifting between low and high as the specified data bit toggles Amplitude Sample 0 Data Marker i i bit 1 i i 100 101 110 110 100 B Note Devices Event Delays NI FGEN compensates for the factors that affect the delays in the digital and analog paths in assuring that the Data Marker event appears within one Sample clock of the waveform output Data Markers as Trigger Outputs A delay of at least 44 Sample clocks exists between the Start trigger and when the analog waveform generation appears on the output connector Therefore synchronizing the signal generator o
29. You can set the initial state of the event e Pulse Each event triggers a pulse for a specified period of time e Level Whilethe event is active it shifts high or low depending on the active state you specify Event Status Events can return their status in two ways Refer to the following table to determine what status can be read for each event type e Live Returns the current state of the event e Latched Returns whether the event has ever been active National Instruments Corporation 2 81 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview The following table describes the event output behaviors and statuses supported by the NI 5450 Event Name Description Output Behavior Status Ready for Start Event Started Event Ready For Start event indicates that the signal generator is configured and ready to receive a Start trigger Started event indicates when the signal generator has received a Start trigger and is generating a waveform Level Level Pulse Live Latched Marker Event A Marker is an event that the device generates in relation to a waveform that is generated The event is configured to occur at the time that a specific location or sample n if the waveform generates on the CH 0 connector If the waveform loops multiple times in a segment the marker generates each time the waveform loops Pulse Toggle Latched Live Data Marker Event A Data M
30. accept or generate a trigger generate a marker accept or generate a Reference clock The function of each PFI line is independent If you are using LabVIEW to program your signal generator and you want to connect external signal generators to the PFI lines you can use the niFgen Configure Sample Clock Source VI the niFgen Configure Reference Clock VI or the niFgen Configure Trigger VI to route external signals to internal sources You can use the niFgen Export Signal VI to route internal signals to the PFI lines on the front panel If you are using LabWindows CVI to program your signal generator you can use the niFgen ConfigureSampleClockSource function the niFgen_ConfigureReferenceClock function or the niFgen_ConfigureTriggerSource function to route external signals to internal sources You can use the niFgen ExportSignal function to route internal signals to the PFI lines on the front panel If you enable a PFI line for output do not connect any external signal source to it doing so can damage the device the computer and the connected equipment NI PXle 5450 User Manual 3 6 ni com Chapter 3 Integration and System Considerations MXI Optimization Application MXI 3 If you are using the MXI 3 interface to control the PXI chassis the MXI 3 Optimization Application must be run prior to using the NI signal generator By default this application runs automatically when Windows starts If you have an initialization tim
31. and configure the amplitude DC offset and start phase of the generation C Example The procedure below provides the basic steps required to configure Frequency List mode For an example of the use of Frequency List mode in C refer to the Fgen Sweep SweepGenerator example for CVI 1 Call the niFgen ConfigureOutputMode function with outputMode set to NTFGEN VAL OUTPUT FREO LIST 2 Optional Call the niFgen_ClearFreqList function to remove a previously created freguency lists from the signal generator memory 3 Call the niFgen CreateFreguist function to set the function type the freguency list and the duration of each step in the list 4 Call the niFgen ConfigureFreglist function to select the active freguency list and configure the amplitude DC offset and start phase of the generation 4 16 ni com Chapter 4 Programming Configure Script Mode You can use Script mode to use scripting to link and loop multiple waveforms in complex combinations using a script LabVIEW Example The procedure below provides the basic steps required to configure Script mode To see a more detailed example of the use of Script mode in LabVIEW refer to the Fgen Arb Script vi example for LabVIEW 1 Call the niFgen Configure Output Mode VI with Output Mode set to Script 2 Write all waveforms that are referenced in the script by calling the niFgen Write Named Waveform VI and associate the proper names to them 3 After your wav
32. bias currents in the electronic National Instruments Corporation 3 1 NI PXle 5450 User Manual Chapter 3 Integration and System Considerations components increase noise accelerate drifts and decrease product life Beyond the maximum specified operating temperatures the device may perform differently than during factory calibration resulting in additional measurement errors Also operating the device outside of the humidity specification gt 80 gt 35 C may cause leakages between circuit components and introduce measurement error To optimize cooling and ensure best performance and reliability the use the following guidelines e Chassis that provide multiple fan speed settings should always be run with fans set on high or auto if applicable to your chassis Never set the fans to low or turn them off S Note In newer NI chassis the settings are HIGH and AUTO in some older NI chassis the fan settings may be HI and LO NI PXle 5450 User Manual e All empty slots in the chassis should be covered with a blank slot filler panel e Remove and clean the inlet filters often to prevent buildup of dust and other foreign material that may restrict airflow e The chassis should be located such that the fan inlets and outlet vents are not obstructed Other objects and equipment should be kept a minimum of 3 inches from the fan inlets For more information about forced air cooling refer to your chassis documentation NI PXI an
33. ee ee Re Se ee ee ee ee ee Re ee ee 3 3 PXUMOdUIeS EE EE N EE RE EE ER OE EA 3 3 erken RA EE EE 3 4 Using PXI Compatible Products with Standard CompactPCI Products 3 4 PXI Trig get Lames BO EE EE EE 3 5 System Reference Clock PXI_CLK10 ooo cece sees ee Re RR ee Re ee 3 6 ABEL MR EE EE ER RE N RE 3 6 MXI Optimization Application wo ese see se ee ee Ge Re ee ee ee ee Re ee ee 3 7 Pd EE ER EE tae ea ees 3 7 MXI 4 and MXI Express Optimization 0 0 cee see se se eke se ee Se Ge ee ee ee 3 7 Chapter 4 Programming Programming State Model cscs chs RR se GEED GN ein Ee gek boe ok Page Vee geo se ed 4 1 General Programming FLOW 200 0 cece see see ee ee ke eris ee Se a Ge Ge ee a ke 4 3 Instrument Driver OVervi W esse sesse ese se se Ge ee ee Re Se Re E ee ee Se ee Re ee 4 4 Creating an Application with NI FGEN and Your ADE eee 4 5 Creating an Application with Lab VIEW ees see sesse ese see se ee ee 4 5 NI FGEN Example Programs for Lab VIEW sesse sees 4 5 Considerations for using the LabVIEW Real Time Modul i eke es nee utilis teehee 4 6 Creating an Application with LabWindows CVI esse sesse se 4 7 NI FGEN Example Programs for LabWindows CVI 4 7 NI PXle 5450 User Manual X ni com Contents Creating an Application with Visual C C eee se ee se ee 4 7 NI FGEN Example Programs for Visual C C 4 8 Special Considerations 0 0 0 0 see se ee se ee Se ee Ge ee ee ee 4 8 FEE GATE
34. for real data points by setting the Data Processing Mode property or the NIFGEN ATTR OSP DATA PROCESSING MODE attribute then it is the rate at which each sample from waveform memory is taken from memory and inserted into the OSP block If the waveform data is configured for complex data points by setting the Data Processing Mode property or the NIFGEN ATTR OSP DATA PROCESSING MODE attribute then it is the rate at which each complex sample is taken from memory and inserted into the OSP block Note When the onboard signal processing is enabled by setting the OSP Enabled property or the NIFGEN_ATTR_OSP_ENABLED attribute you cannot set the Sample Rate property or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute NI PXle 5450 User Manual 2 28 ni com Chapter 2 NI 5450 Overview Using an External Clock with the OSP Block Some applications may require lower jitter or phase noise than is provided by the onboard High Resolution clock You can use an external clock source to achieve spectral purity at any arbitrary I Q rate To determine the frequency of the sample rate for the external clock source complete the following steps 1 Set the Sample Clock Source property or the NIFGEN_ATTR_SAMPLE_CLOCK_SOURCE attribute to the external clock source you are using 2 Set the IQ Rate property or the NIFGEN_ATTR_OSP_IQ_RAT attribute 7 3 Read the value of the Sample Rate proper
35. frequency aliases back in the passband falsely appearing as a 1 MHz sine wave Shannon s Sampling Theorem Shannon s Sampling theorem states that a digital waveform must be updated at least twice as fast as the bandwidth of the signal to be accurately generated The same image that was used for the Nyquist example can be used to demonstrate Shannon s Sampling theorem National Instruments Corporation 5 3 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals The following figure shows a desired 5 MHz sine wave generated by a 6 MS s DAC The solid line represents the desired waveform and the arrows represent the digitized samples that are available to recreate the continuous time 5 MHz sine wave The dotted line indicates the signal that would be seen for example with an oscilloscope at the output of a DAC NI PXle 5450 User Manual In this case the high frequency sine wave is the desired signal but was severely undersampled by only being generated by a 6 MS s DAC the actual resulting waveform is a 1 MHz signal In systems where you want to generate accurate signals using sampled data the sampling rate must be set high enough to prevent aliasing Aliased Images An aliased image is a frequency component that appears in continuous time waveforms being recreated from discrete time digital waveforms The frequencies where these extra components appear are related to both the frequency of the
36. generator to perform an action such as starting or stopping a generation operation Triggers can be internal software generated or external External digital triggers can be several different types External triggers can be re exported and along with events can allow you to synchronize the hardware operation with external circuitry or other NI devices When triggering your NI signal generator you can select the type of trigger the trigger source and the trigger mode that you want to use 2 72 ni com Chapter 2 NI 5450 Overview Triggers Summary The following table describes the triggers supported by signal generators The Supported Types column denotes which trigger types are valid for a given trigger Trigger Name Supported Types Description Start Digital Edge Software The Start trigger transitions a device from an idle state to a generation state where the device can respond to Sample clocks Script Digital Edge Digital The Script trigger is a general purpose trigger with a Level Software role that is entirely determined by the context of the generation script A script allows you to create sophisticated generation operations For example the script could configure the device to generate waveform A then wait for the Script trigger then generate waveform B You can create multiple Script triggers for use in your application Once a digital edge Script trigger has been received that trigger remains tru
37. gt dd Ee and eee Q gt Gain Q P DAGO Programmable VO Pulse Shaping Gain amp Offset Control and Interpolation Baseband I Q interpolation allows the OSP block to interpolate complex data signals at a low sample rate up to a high sample rate Arbitrary pulse shaping of the data can also be done in the FIR filter For baseband VO interpolation complete the following steps 1 Enable onboard signal processing by setting the OSP Enabled property or the NIFGEN_ATTR_OSP_ENABLED attribute 2 Set the OSP mode to Baseband by calling the OSP Mode property or the NIFGEN_ATTR_OSP_MODE attribute 3 Specify the use of complex numbers for the waveform data by setting the Data Processing Mode property or the NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE attribute 4 Set the IQ Rate property or the NIFGEN_ATTR_OSP_IQ_RATE attribute to the low sample rate of the waveform data 5 Set the FIR Filter Type property or the NIFGEN_ATTR_OSP_FIR_FILTER_TYPE attribute 6 Set the corresponding filter parameter 7 Optional Shift the frequency by calling the Frequency Shift property or the NIFGEN_ATTR_OSP_FREQUENCY_SHIFT attribute Download the low sample rate waveform s to the signal generator 9 Read the sample rate by calling the Sample Rate property or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute NI PXle 5450 User Manual 2 32 ni com Chapter 2 NI 5450 Overview Baseband Interpolation Considerations The NI 5450 implements baseband interpolation
38. higher sample rate also captures more waveform details The following figure illustrates a 1 MHz sine wave generated by a sampled 2 MS s DAC and a 20 MS s DAC The faster DAC generates 20 points per cycle of the expected signal compared with 2 points per cycle with the slower DAC In this example the higher sample rate more accurately defines the waveform shape 1p m Sample Rate 2 MS s e Sample Rate 20 MS s NI PXle 5450 User Manual 5 2 ni com Chapter 5 Signal Generation Fundamentals Nyquist and Shannon s Sampling Theorems The Nyquist theorem concerns digital sampling of a continuous time analog waveform while Shannon s Sampling theorem concerns the creation of a continuous time analog waveform from digital discrete samples Nyquist Theorem The Nyquist theorem states that an analog signal must be sampled at least twice as fast as the bandwidth of the signal to accurately reconstruct the waveform otherwise the high frequency content creates an alias at a frequency inside the spectrum of interest passband An alias is a false lower frequency component that appears in sampled data acquired at too low a sampling rate The following figure shows a 5 MHz sine wave digitized by a 6 MS s analog to digital converter ADC In this figure the solid line represents the sine wave being digitized while the dotted line represents the aliased signal recorded by the ADC at that sample rate The 5 MHz
39. in order to reduce the power of aliased images Interpolation is a process that effectively turns a lower sample rate into a higher sample rate Because the signal is now at a higher sample rate images are moved to higher frequencies where they fall in the rejection band of the image rejection filter and are suppressed NI FGEN automatically selects the largest interpolation factor to achieve the maximum possible DAC sample rate The interpolated sample rate can then be read with the Sample Rate property or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute 3 Note For optimum performance National Instruments recommends maintaining the sample rate between 270 MS s and 400 MS s due to the fixed frequency characteristics of the image rejection filter For more information about the image rejection filter refer to the NI 5450 specifications Interpolation Settings To determine the total interpolation and interpolated sample rate divide 400 MS s by your desired sample rate and round down to the nearest step as noted in the Interpolation table for your total interpolation value Then consult the following table for settings that will allow you to achieve your desired interpolated sample rate yl Note With OSP enabled Desired Sample Rate Data Rate Symbol Rate x Samples Symbol Example At a desired sample rate of 4 5 MS s the total interpolation will be determined by the following calculations 400 MS s 4 45 MS s 89 88x total in
40. interpolate signals at a low sample rate up to a high sample rate Arbitrary pulse shaping of the data can also be done in the FIR filter For baseband interpolation complete the following steps 1 Enable onboard signal processing by setting the OSP Enabled property or the NIFGEN_ATTR_OSP_ENABLED attribute Specify the use of real numbers for the waveform data by setting the Data Processing Mode property or the NIFGI Set th e IQ Rate property or the NIFGEN ATTR OSP TO RAT EN ATTR OSP DATA PROCESSING MODE attribute 7 attribute to the low sample rate of the waveform data Set th NIFGI Set th e FIR Filter Type property or the EN ATTR OSP FIR FILTER TYP E attribute e corresponding filter parameter Disable the carrier by setting the Carrier Enabled property or the NIFGI EN ATTR OSP CARRIER ENABLEI D attribute Download the low sample rate waveform s to the signal generator 2 31 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Baseband 1 Q Interpolation The following figure shows the behavior of the OSP block during baseband TQ interpolation Onboard Signal Processing Ee EF Dda e EE EE ie ED Waveform Output VO Freguency Memory Engine gt Rate Shift SEE
41. ni com manuals Accessories Before shipping your signal generator NI calibrated your device to ensure that all features are within specifications Calibration is a set of operations that compares the values indicated by a measuring instrument or measuring system to the corresponding values realized by external standards You can use the results of calibration to determine the measurement error and can then correct for it in the adjustment process The calibration process consists of verifying adjusting and reverifying a device During verification you compare the measured performance to an external standard of known measurement uncertainty to confirm that the product meets or exceeds specifications During adjustment you correct the measurement error of the device by adjusting the calibration constants and storing the new calibration constants in the EEPROM The host computer reads the calibration constants and the software uses them to compensate for errors in the data and to present calibrated data to the user National Instruments offers a variety of products to use with your signal generator including cables and other accessories Visit ni com for more information National Instruments Corporation 2 89 NI PXle 5450 User Manual Integration and System Considerations This section contains information about integrating NI signal generators into a PXI based or a PCI based measurement system The PXI architecture h
42. particular device or measurement function National Instruments Corporation 4 5 NI PXle 5450 User Manual Chapter 4 Programming NI PXle 5450 User Manual To browse the NI FGEN examples available in LabVIEW launch LabVIEW click Find Examples and navigate to Hardware Input and Output Modular Instruments NI FGEN For the installation location of the LabVIEW example files refer to the NI FGEN Instrument Driver Readme Considerations for using the LabVIEW Real Time Module To develop an NI FGEN application in the LabVIEW Real Time Module follow the same steps used for developing any application in the LabVIEW Real Time Module with the addition of using the NI FGEN LabVIEW VIs Supported LabVIEW Versions LabVIEW Real Time Module 7 1 or later Unsupported Hardware The following signal generators are not supported as targets for your LabVIEW RT application e NI PXI PCI 5401 e NI PXI PCI 5411 e NI PXI PCI 5431 Unsupported Features When using the National Instruments signal generators with LabVIEW RT the following features are not supported e External calibration e Express VIs e FGEN Soft Front Panel Related Documentation e For configuration instructions for remote systems refer to the MAX Remote Systems Help in Measurement amp Automation Explorer MAX by selecting Help Help Topics Remote Systems in MAX e For more information about the LabVIEW Real Time Module refer to the LabVIEW Real Time Module U
43. small waveform or if triggers are advancing the segments in a sequence very rapidly When this occurs NI FGEN reports Error 1074115901 0xBFFA4AC3 Device Data Underflow The simplest way to avoid this condition is to follow the minimum waveform size guidelines in the specifications If these rules are followed a data underflow error will not NI PXle 5450 User Manual 2 62 ni com Chapter 2 NI 5450 Overview occur under any sample rate You can develop applications that generate waveforms smaller than those listed in the device specifications at slower sample rates If a data underflow occurs NI FGEN reports the error when the generation is aborted This is typically accomplished by calling the niFgen Abort Generation VI or the niFgen_AbortGeneration function or if you call the niFgen Wait Until Done or niFgen Is Done VIs or the niFgen_WaitUntilDone or niFgen_IsDone functions while the device is generating a signal To monitor error conditions during waveform generation the niFgen Is Done VI or the niFgen TsDone function can be called repeatedly while the device is generating a signal The maximum waveform size allowed depends on the remaining available space in the onboard memory of the device The remaining available space depends on factors such as any waveforms and generation instructions currently occupying memory space in the onboard memory The maximum allowable size equals the memory size of the device minus the data already in
44. specified number of times instead of just once Start Start Start Trigger Trigger Trigger r Last Sample Generated Continuously End of Waveform Arbitrary Sequence Mode NI PXle 5450 User Manual The waveforms you define in the sequence list generate one segment at a time each time a Start trigger occurs The waveform loops as many times as has been configured for that particular segment After the generation of a segment has halted the last sample of the waveform repeats continuously until the next Start trigger is received After the sequence list is exhausted the waveform generation returns to the first segment and subsequent Start triggers restart the process Start Start Start Start Trigger Trigger Trigger Trigger i Last Sample of Last Seqment 4 Generated Continuously End of Segment 2 78 ni com Chapter 2 NI 5450 Overview Burst Trigger Mode In Burst trigger mode calling the first Start trigger begins waveform generation The waveform then generates continually The following table provides more information about waveform generation behavior in Arbitrary Waveform and Arbitrary Sequence output modes Output Mode Trigger Behavior Arbitrary Waveform Mode Burst trigger mode operates the same as Continuous trigger mode when the device is operating in Arbitrary Waveform mode Arbitrary Sequence Mode Each waveform you define in the sequence list generate
45. that the transmission line is matched to its terminations The source and load impedances should equal the characteristic impedance of the transmission line as this minimizes signal reflections The presence of impedance discontinuities or mismatches degrade the amplitude and phase accuracy as well as the temporal fidelity of waveforms generated with a signal generator One of the most common mismatch errors encountered in such measurements is shown in the following figure Characteristic Impedance 50 Q Delay t 759 To DAC V 759 Source Coaxial Input Load Cable In this example selectable source impedances are provided at the signal generator outputs to accommodate the most popular coaxial cable characteristic impedances 50 Q and 75 National Instruments Corporation 5 7 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals The following figure shows what happens when as in this example a coaxial cable of the wrong characteristic impedance 50 Q is used with 75 Q source and load impedances V Signal Generator With Matched Cable Voltage O t 3t 5t 7t 9t Time The pulse encounters impedance mismatches at each end of the cable causing the pulse to be partially reflected The reflected pulse traverses the cable back and forth numerous times diminishing at each end by the reflection coefficient T where v reflected voltage v incident voltage z termin
46. to write the first part of the waveform data to the streaming waveform in onboard memory 9 Tip When transferring large blocks of waveform data break the data into smaller blocks and call the niFgen Write Waveform VI or the niFgen_WriteWaveform function multiple times The data is appended seguentially A computer can allocate smaller blocks of a large waveform faster than allocating a single large contiguous block in memory Depending on the amount of RAM on the computer transferring ten 16 MB blocks may be faster than transferring one 160 MB block 160 MB fai Write First Portion to Onboard Memory NI PXle 5450 User Manual 2 66 ni com Chapter 2 NI 5450 Overview Begin generating the waveform Call the niFgen Initiate Generation VI or the niFgen_InitiateGeneration function to begin the waveform generation As the waveform generates space in the streaming waveform becomes free As Waveform is Generated Onboard Memory Becomes Free KH a Ge N AG EA 160 MB EA wren Monitor available memory as the waveform generates Use the Space Available in Streaming Waveform property or the NIFGEN ATTR STREAMING SPACE AVAILABLE IN WAVEFORM attribute to determine how much of the streaming waveform is free for writing new data As the waveform generates space becomes available to write more waveform data After a certain amount say 10 percent of the alloc
47. until the configured trigger occurs When the device recognizes a trigger condition the device immediately shifts out of this state and generates a Started event First Data Appears This state is temporary and indicates that waveform data is just starting to appear at the front panel connector Generation In the Generation state the device is generating a waveform as specified by the session attributes configured Dynamic or on the fly properties and attributes such as the Amplitude Arbitrary Waveform Gain and Arbitrary Waveform Offset properties or the NIFGEN_ATTR_FUNC_AMPLITUDE NIFGEN_ATTR_ARB_GAIN and the NIFGEN_ATTR_ARB_OFFSET attributes are applied immediately to hardware Started Event trigger is generated as the device recognizes triggers Depending on the configured trigger mode the device may stay in the Generation state until the generation is aborted Dynamic properties and attributes such as amplitude gain and offset can be applied to the device immediately if you set them while the session is in the Generation state Refer to the NI FGEN LabVIEW Reference or the NI FGEN C Function Reference for information about the specific property or attribute that you want to set during generation Done The device has completed the waveform generation as configured for this session This state only occurs at the end of a generation state configured for the Single trigger mode The device remains in th
48. waveforms in complex combinations using a script A script is a series of instructions that indicates how waveforms saved in the onboard memory should be sent to the DUT The script can specify the order in which the waveforms are generated the number of times they are generated and the triggers and markers associated with the generation The following are the basic steps you should use to create your script 1 Call the niFgen Configure Output Mode VI or the niFgen_ConfigureOutputMode function to switch to Script mode 2 60 ni com Chapter 2 NI 5450 Overview 2 Write all waveforms that are referenced in the script by calling the niFgen Write Named Waveform VI or one of the niFgen Write Named Waveform Functions and associate the proper names to them 3 After your waveforms are written to your device call the niFgen Write Script VI or the niFgen WriteScript function to write the script s containing the generation instructions to be executed The script you write can manage waveform generation based on multiple waveforms and triggers For example you could download waveforms A B C and D into device memory You could then write a script that would wait for a trigger to initiate generation and upon receiving this trigger generate waveform A three times with a marker at position 16 each time and finally generate waveforms B C and D twice BCDBCD The following is the script of this example script myFirstScript wait until scriptT
49. waveforms such as sine square triangle etc LabVIEW Example The procedure below provides the basic steps required to configure Standard Function mode For a more detailed example of the use of Standard Function mode in LabVIEW refer to the Fgen Basic Standard Function vi example for LabVIEW 1 Call the niFgen Configure Output Mode VI Set Output Mode to Standard Function 2 Choose the type of waveform you would like to generate and set the Waveform parameter of the niFgen Configure Standard Waveform VI to the waveform you have chosen C Example The procedure below provides the basic steps required to configure Standard Function mode For a more detailed example of the use of Standard Function mode in C refer to the BasicStandardFunction example for CVI 1 Call the niFgen configureOutputMode function Set outputMode to NIFGEN_VAL_OUTPUT_FUNC 2 Choose the type of waveform you would like to generate and set the waveform parameter of the niFgen_configureStandardWaveform function to the waveform you have chosen 4 12 ni com Chapter 4 Programming Configure Arbitrary Waveform Mode You can use Arbitrary Waveform mode to generate waveforms from user created or user provided waveform arrays of numeric data LabVIEW Example The procedure below provides the basic steps required to configure Arbitrary Waveform mode For a more detailed example of the use of Arbitrary Waveform mode in LabVIEW refer to the Fgen Basic
50. 0 1 gt Multiple Using Using Using Using Using Using Using Using Device NI TClk NI TClk NI TClk NI TClk NI TClk NI TClk NI TClk NI TClk Synchroni except for except for except for zation Standard Standard Standard Function Function Function mode mode mode National Instruments Corporation 1 7 NI PXle 5450 User Manual NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Events Ready for Yes Yes Yes Yes Yes Yes Yes Yes Start Started Yes Yes Yes Yes Yes Yes Yes Yes Done Yes Yes Yes Yes Yes Yes Yes Yes Marker Yes Yes Yes Yes Yes Yes Data Yes Yes Yes Yes Yes Marker Clocking Sample 100 MS s 100 MS s Internal Internal 5 MS s to Internal Internal Internal Rate Sample Sample 200 MS s Sample Sample Sample Update clock clock clock clock clock Rate before 10 S s to 10 S s to 10 S s to 10 S s to 12 2 kS s to filtering and 100 MS s 100 MS s 100 MS s 100 MS s 400 MS s interpola External External External External External tion Sample Sample Sample Sample Sample clock clock clock clock clock 10 S s to 10 S s to 10 S s to 10 S s to 10 MS s 105 MS s 105 MS s 105 MS s 105 MS s 20 MS s to 400 MS s NI PXle 5450 User Manual 1 8 ni com NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Reference Internal Internal Internal Internal Internal Internal Internal Internal Clock none none non
51. 50 Overview Output Enable You can disable the analog output signal at the differential channel connectors by controlling the output enable relay as shown in the following figure CHO Analog Output Path Output Enable 50 Q Analog CHO Output o Path 50Q Output Enable When the output enable relay is disabled the output signal is connected to ground through a 50 Q resistance The output enable relay is enabled for normal waveform generation and connects the differential channel SMA connectors to the Analog Output path You can change the output enable state at any time during waveform generation and generation continues internally You can enable the output by calling the niFgen Output Enable VI or the niFgen ConfigureOutputEnabled function yl Note The signal generator uses mechanical relays to switch between the output enable states When you change a setting that causes a relay to switch electromechanical relay bouncing interrupts the output signal for up to 10 ms NI PXle 5450 User Manual 2 18 ni com Chapter 2 NI 5450 Overview Multichannel Configuration The NI 5450 has two channels that can be configured as active by calling the niFgen Configure Channels VI or the niFgen ConfigureChannels function with a string containing the channel s that you wish to activate You must configure the channels immediately after calling the niFgen Initialize VI or the niFgen init f
52. 520 640 C 960 1 920 1 920 D 492 984 1 024 E 516 1 032 1 152 F 604 1 208 1 280 Memory Size 7 040 Number of Segments in Memory Sequence Calculation Bytes Rounded Size 10 000 160 128 x 128 160 128 256 10 000 ni com Chapter 2 NI 5450 Overview 3 An application requires using five waveforms with the following sizes 10 000 1 000 000 2 000 000 30 000 000 and 5 000 samples The waveforms are generated by using Arbitrary Sequence mode and Stepped trigger mode to configure 2 000 segments in a sequence list The following table shows all the numbers used to determine the total memory stored in the onboard memory 66 190 464 bytes Waveforms Samples Bytes Rounded Size A 10 000 20 000 20 096 B 1 000 000 2 000 000 2 000 000 C 2 000 000 4 000 000 4 000 000 D 30 000 000 60 000 000 60 000 000 E 5 000 10 000 10 112 Memory Size 66 030 208 Number of Segments in Memory Sequence Calculation Bytes Rounded Size 2 000 208 80 x 160 208 160 256 2 000 Total Onboard Memory Used 66 190 464 bytes National Instruments Corporation 2 51 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview NI PXle 5450 User Manual An application requires using seven waveforms with the following sizes 1 000 2 000 2 000 10 000 20 000 500 and 260 samples The waveforms are generated by using Arbitrary Sequence mode and Continuous trigger mode to configure 100 segments in a seq
53. 7 20 000 1 000 000 13 8 1 1 0 National Instruments Corporation 2 45 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Onboard Memory for Multichannel Waveform Generation On multichannel devices onboard memory is allocated separately for each configured channel When you write a waveform to the onboard memory of a multichannel device the space required for the waveform is allocated in the onboard memory for each channel You can write different data to the waveform allocated for each channel as long as the data written requires the same amount of memory on each channel For example Waveform can contain a ramp wave on channel 0 and a square wave on channel 1 as shown in the following figure Waveform Waveform TU B Channel 0 Waveform 1 JUL Waveform 4 JV B Channel 1 NI PXle 5450 User Manual Waveform and Generation Instruction Memory Size Waveform Memory Size Waveforms are stored in the NI 5450 onboard memory in contiguous blocks These blocks are allocated in multiples of 128 bytes This allocation style means that while waveform sizes may be multiples of two samples four bytes on the NI 5450 the amount of onboard memory allocated for each waveform is a multiple of 128 bytes The following figure represents the total memory of a device and shows memory that was initially empty but it now has multiple
54. AILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS INCLUDING THE RISK OF BODILY INJURY AND DEATH SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE TO AVOID DAMAGE INJURY OR DEATH THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES INCLUDING BUT NOT LIMITED TO BACK UP OR SHUT DOWN MECHANISMS BECAUSE EACH END USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION INCLUDING WITHOUT LIMITATION THE APPROPRIATE DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Compliance Compliance with FCC Canada Radio Frequency Interference Regulations Determining FCC Class The Federal Communications Commission FCC has rules to protect wireless communications from interference The FCC places digital electronics into two classes These classes are known as Class A for use in industrial commercial locations only or Class B for use in residential or commercial locations All National Instruments NI products are
55. AR OE N RR 4 8 Creating an Application with Visual Basic eee eee ee se ee 4 8 IE DE ASM Oes EIER N EE EE RR N HE EE i3 4 9 Example Programs RE spa geeesvees 4 9 Basic EA EE RE OE 4 9 Vn Ze RE EE EE EE ER EE a Pa KO ARE EE 4 10 Conti suration ss RE OR EE ER 4 11 ede EURO 4 11 Configure Output Mode oo eee eee ee ee ee Ge ee ee ee ee ee 4 12 Configure Standard Function Mode ees see se se ee ee 4 12 Configure Arbitrary Waveform Mode iese esse sesse se 4 13 Configure Arbitrary Sequence Mode 1 0 0 eee eee 4 14 Configure Frequency List Mode sesse see se ee ee 4 16 Configure Script Mode 0 eee ee see se ee ee ee ee ke ee 4 17 Initiate Generation esse sesse sere esse ge DERDE GR caveasdges N eg Sad GE Kees Dee Re eg tas 4 19 DiE ERA RE OE ER EE N OE ARA 4 19 Abort to Ground aerie n aieo eN LE BEDE SEK ERGE Se AR ESE DE EE Gees 4 19 Abort to a Known Voltage ee ee ee ek ee ee Se ee ee ee 4 20 Closing USE RE OE N EE EE 4 21 MIE se Error Codes EA ARE OE EE EE EE EE 4 21 USE EE EE EE EE EE 4 23 Configuring an Internal Sample Clock sesse se se ee Ee ee Re ee 4 23 Configuring an External Sample Clock sesse sesse se ee se ee ee ee ee ee ee 4 24 Configuring a Reference Clock esse see ee se ke SA ee ee Re ee ee ee ke 4 24 GEMMER RR RR EER aas 4 25 Creating a Marker Event 000 0 sesse ese se ee ee ee ee ee ek Se ee Se ee ee ee ee 4 26 Creating a Marker Event in Arbitrary Waveform Mode 4 26
56. Arb Waveform vi or the Fgen Arbitrary Waveform vi examples for LabVIEW 1 Call the niFgen Configure Output Mode VI with Output Mode set to Arbitrary Waveform 2 Optional Call the niFgen Clear Arbitrary Memory VI This clears any previously created arbitrary waveforms sequences and scripts from the signal generator memory Choose one of the following two options for creating your arbitrary waveform Option 1 Allow NI FGEN to configure the size and allocated space of your waveform 1 Call the niFgen Create Waveform poly VI This VI creates a waveform the size of the data you provide 2 Call the niFgen Configure Arbitrary Waveform VI to configure the gain and offset of the waveform Option 2 Manually configure the size and allocated space of your waveform 1 Call the niFgen Allocate Waveform VI to specify the size of the waveform to allocate in the onboard memory of the signal generator 2 Call the niFgen Write Waveform poly VI to write waveform data to the onboard memory you allocated in step 3 3 Call the niFgen Configure Arbitrary Waveform VI to configure the gain and offset of the waveform National Instruments Corporation 4 13 NI PXle 5450 User Manual Chapter 4 Programming NI PXle 5450 User Manual C Example The procedure below provides the basic steps required to configure Arbitrary Waveform mode For a more detailed example of the use of Arbitrary Waveform mode in C refer to the BasicAr
57. Creating a Marker Event in Arbitrary Sequence Mode 4 27 Creating a Marker Event in Script Mode ou eee ee se se se ee ee 4 27 Creating a Data Marker Event eee se see se ee se ee ek Se ee ee ee ee ee 4 28 Configuring an Application for Streaming sesse see se se ee ee Re ee ee 4 29 Configuring Your Application for Direct DMA eee 4 31 Simulation Modes AE ses Re ES Ee ge Roe Ge oge ee ge EG GER eRs Ee GEE Ese eg Ses 4 32 National Instruments Corporation xi NI PXle 5450 User Manual Contents Chapter 5 Signal Generation Fundamentals Bandwidth and Passband Flatnes iese ee ee se se ee se ee ee ee Re Re Se ee Se ee Se ee Sample Rate 2 4 devise vein lee OE Re el dees Ee ae Ed SE E ae De gee EE ig Nyquist and Shannon s Sampling Theorems cece se ee se ee Ge Re ee Nyquist Theoren ie Ee es ee Reg Di dk ei Ee Ge RR bee oe Pe be sege eg Ee Shannon s Sampling Theorem see sesse se se Se ee ee ee ee AltasedrImages nr ese Be EE oe EE Ee ee ees DAG Resol onic SEE GR DE EE GE ee taki Oe ee ee Ge Ge De is the Appendix A Technical Support and Professional Services NI PXle 5450 User Manual xii ni com About This Manual Conventions This user manual explains the fundamental and advanced concepts necessary for using the NI 5450 arbitrary function generator and describes the features functions and operation of the signal generator lt gt gt Ao bold italic The
58. FCC Class A products Depending on where it is operated this Class A product could be subject to restrictions in the FCC rules In Canada the Department of Communications DOC of Industry Canada regulates wireless interference in much the same way Digital electronics emit weak signals during normal operation that can affect radio television or other wireless products All Class A products display a simple warning statement of one paragraph in length regarding interference and undesired operation The FCC rules have restrictions regarding the locations where FCC Class A products can be operated Consult the FCC Web site at www fcc gov for more information FCC DOC Warnings This equipment generates and uses radio frequency energy and if not installed and used in strict accordance with the instructions in this manual and the CE marking Declaration of Conformity may cause interference to radio and television reception Classification requirements are the same for the Federal Communications Commission FCC and the Canadian Department of Communications DOC Changes or modifications not expressly approved by NI could void the user s authority to operate the equipment under the FCC Rules Class A Federal Communications Commission This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to part 15 of the FCC Rules These limits are designed to provide reasonable protection against h
59. FGEN_ATTR_GAIN_DAC_VALUE attribute Analog Gain Settings The following table summarizes the maximum and minimum gain setting that you can apply for the NI FGEN Analog path options Refer to the device specifications for more information about gain resolution Analog Path Gain Summary Matched Load Impedance NI FGEN Analog Path Maximum Minimum Gain Value Gain Value Direct Path without flatness correction 0 5 0 354 Direct Path with flatness correction 0 4 0 284 Note Gain is unitless Note Digital gain is applied to the digital data before the data is passed to the DAC Because relays are not used digital gain allows glitch free gain control at the expense of dynamic range NI PXle 5450 User Manual 2 16 ni com Chapter 2 NI 5450 Overview Digital Gain Digital gain multiplies waveform data by a factor you specify in the Digital Gain property or the NIFGEN_ATTR_DIGITAL_GAIN attribute before converting the data to an analog signal in the DAC Digital gain can be changed during generation without the glitches caused by relay switching that are common when changing analog gains However the output resolution of the DAC is a function of digital gain meaning that only analog gain makes full use of the resolution of the DAC Flatness Correction The NI 5450 can use flatness correction to ensure a consistent power level when generating arbitrary waveforms at any frequency Flatness co
60. FI Connectors PFI 0 and PFI 1 are bidirectional connectors As an input the PFI terminals can accept a trigger from an external source that can start or step through waveform generation As an output the PFI lines route a signal out from the following sources e Marker events e Start trigger e PLL Reference clock source e Sample Clock Out with K where K is an integer used to divide the Sample clock e Started Done and Ready for Start events e Sample clock timebase with M where M is an integer used to divide the Sample clock timebase frequency e Script trigger Refer to the device specifications for information about acceptable input signal characteristics for the PFI lines and output signal characteristics National Instruments Corporation 2 7 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview ACCESS and ACTIVE LEDs The ACCESS and ACTIVE LEDs indicate the status of the PXIe module ACCESS LED The ACCESS LED indicates basic hardware status as shown in the following table Color Indications Off Device is not yet functional or the device has detected a problem with a power rail Amber The device is being accessed Green The device is ready to be programmed by NI FGEN ACTIVE LED The ACTIVE LED indicates the device state as shown in the following table Color Indications Off Device is not generating Amber The device is armed an
61. GEN reduces your program development time and simplifies device control by eliminating the need to learn a complex programming protocol for your device Refer to the NI FGEN Instrument Driver Readme for more information You can access this document by selecting Start All Programs National Instruments NI FGEN Documentation Creating an Application with NI FGEN and Your ADE This topic covers how to begin using NI FGEN with your application development environment ADE and lists any files that you need to include in your application To successfully build your application you need to have NI FGEN installed along with one of the following ADEs e NI LabVIEW e NI LabVIEW Real Time e NI LabWindows CVI e Microsoft Visual C C e Microsoft Visual Basic Creating an Application with LabVIEW This topic assumes that you are using LabVIEW to manage your code development and that you are familiar with the ADE To develop an NI FGEN application in LabVIEW follow these general steps 1 Open an existing or new LabVIEW VI 2 From the Function palette locate the NI FGEN VIs at Instrument VOS Instrument Drivers NI FGEN 3 Click the Vis that you want to use and drop them on the block diagram to build your application NI FGEN Example Programs for LabVIEW If you are using Lab VIEW 7 0 or later you can use the NI Example Finder to search or browse examples NI FGEN examples are classified by keyword so you can search for a
62. I 5450 Overview FIR Filter Type Use the FIR Filter Type property or the NIFGEN_ATTR_OSP_FIR_FILTER_TYPE attribute to set the FIR filter type The following filter types are supported e Flat e Raised Cosine e Root Raised Cosine Common Onboard Signal Processing Applications The OSP block is particularly useful for the following common applications e Arbitrary Waveform Generation e Baseband Interpolation e Baseband I Q Interpolation Arbitrary Waveform Generation The following figure shows the behavior of the OSP block during arbitrary waveform generation Waveform Memory Output Engine Digital Gain DAG Onboard Signal Processing NI PXle 5450 User Manual For normal arbitrary waveform generation disable onboard signal processing by setting the OSP Enabled property or the NIFGEN_ATTR_OSP_ENABLED attribute 2 30 ni com Baseband Interpolation The following figure shows the behavior of the OSP block during baseband Chapter 2 NI 5450 Overview Waveform Memory Output Engine VO Rate interpolation Onboard Signal Processing Pre Filter Pre Filter Filtering Digital DAC gt Gaini P offset gt and Interpolation gt Gain 1 Frequency Shift National Instruments Corporation Baseband interpolation allows the OSP block to
63. MBER attribute 2 Set the output polarity of the data marker event using the NIFGEN_ATTR_DATA_MARKER_EVENT_LEVEL_POLARITY attribute 3 To export the data marker use the niFgen_ExportSignal function To determine all possible signal routes for your device refer to Signal Routing 3 Note When exporting data markers you must specify the signal identifier for the data marker using the niFgen_ExportSignal function NI PXle 5450 User Manual 4 28 ni com Chapter 4 Programming Configuring an Application for Streaming The following instructions are a guide for configuring your application for streaming For a more detailed programmatic example refer to Fgen Arb Waveform Streaming vi for LabVIEW or ArbitrarywWaveformStreaming prj for LabWindows CVI LabVIEW Example The procedure below provides the basic steps required to configure streaming For a more detailed example of the use of streaming in LabVIEW refer to the Fgen Arb Waveform Streaming vi example for LabVIEW 1 Call the niFgen Allocate Waveform VI to specify the amount of onboard memory to reserve for streaming 2 Set the Streaming Waveform Handle property to the waveform handle returned in step 1 3 Call the niFgen Write Waveform VI to write the first part of the waveform data to the streaming waveform in onboard memory Tip When transferring large blocks of waveform data break the data into smaller blocks an
64. NI PXle 5450 User Manual National Instruments 400 MS s 16 bit differential generator for the PXI Express platform July 2008 7 NATIONAL 372622A 01 ON INSTRUMENTS Worldwide Technical Support and Product Information ni com National Instruments Corporate Headquarters 11500 North Mopac Expressway Austin Texas 78759 3504 USA Tel 512 683 0100 Worldwide Offices Australia 1800 300 800 Austria 43 662 457990 0 Belgium 32 0 2 757 0020 Brazil 55 11 3262 3599 Canada 800 433 3488 China 86 21 5050 9800 Czech Republic 420 224 235 774 Denmark 45 45 76 26 00 Finland 358 0 9 725 72511 France 01 57 66 24 24 Germany 49 89 7413130 India 91 80 41190000 Israel 972 3 6393737 Italy 39 02 41309277 Japan 0120 527196 Korea 82 02 3451 3400 Lebanon 961 0 1 33 28 28 Malaysia 1800 887710 Mexico 01 800 010 0793 Netherlands 31 0 348 433 466 New Zealand 0800 553 322 Norway 47 0 66 90 76 60 Poland 48 22 328 90 10 Portugal 351 210 311 210 Russia 7 495 783 6851 Singapore 1800 226 5886 Slovenia 386 3 425 42 00 South Africa 27 0 11 805 8197 Spain 34 91 640 0085 Sweden 46 0 8 587 895 00 Switzerland 41 56 2005151 Taiwan 886 02 2377 2222 Thailand 662 278 6777 Turkey 90 212 279 3031 United Kingdom 44 0 1635 523545 For further support information refer to the Technical Support and Professional Services appendix To comment on National Instruments documentation refer to the National Instruments Web site at ni com info and en
65. R_OSP_OVERFLOW_ERROR_REPORTING attribute National Instruments Corporation 2 23 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview FIR Filter Type Flat Passband Value 0 40 This lowpass filter is designed to give a flat response until the passband value The passband value is a fraction of the I Q Rate coming into the FIR filter Use the Flat Filter Passband property or the NIFGEN_ATTR_OSP_FIR_FILTER_FLAT_PASSBAND attribute to set the passband value UN Caution The Flat filter stopband does not begin until 0 6 x Q Rate If you provide data that has frequency content above 0 4 x J Q Rate then aliasing occurs in the output spectrum NI recommends you keep all frequency content below 0 4 x I Q Rate when using the Flat filter The following diagram shows the Flat Filter response with a passband of 0 4 The frequency axis is scaled as a fraction of the I Q Rate Magnitude dB IG O 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 Frequency Hz NI PXle 5450 User Manual 2 24 ni com Chapter 2 NI 5450 Overview FIR Filter Type Raised Cosine Alpha Values 0 1 to 0 4 This lowpass filter is commonly used in communications applications The passband of the raised cosine filter stops at 0 5 x 1 of the VO Rate The stopband of the raised cosine filter begins at 0 5 x 1 of the VO Rate The transition band of the raised cosine filter in dB follows the following formula Ideal Raised Co
66. XI Express signal generators Average data transfer rates are highly system dependent The following table is intended to give you an idea of the average sustainable transfer rates using 16 bit or 2 byte samples PXI and PCI Data Source Data Rate MB s Host memory on desktop computer or PXI 90 to 115 embedded controller Desktop IDE or SATA hard drive 55 to 707 Laptop or low RPM hard drive 25 to 307 Host memory on desktop across MXI 3 to 25 PXI board Host memory on desktop across MXI 4 to 25 PXI board All data rates highly dependent on chipset Measurements were taken using the Windows API for unbuffered file I O PXI Express Data Source Data Rate MB s Host memory on desktop computer or PXI 524 embedded controller Desktop IDE or SATA hard drive 310 All data rates highly dependant on chipset These numbers were obtained using several file I O optimizations National Instruments Corporation 2 69 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview NI PXle 5450 User Manual Improving Streaming Performance To improve your maximum sustainable transfer rate for streaming consider the following recommendations Adjust the Data Transfer Block Size property or the NIFGEN ATTR DATA TRANSFER BLOCK SIZE attribute The default data transfer block size for NI FGEN is 2 MS or 4 MB If you were to write a 16 MB waveform to the signal generator th
67. Yes No Note Sample Clock The clock signal that tells the DAC when to convert the digital waveform values to an analog voltage The Sample clock frequency is referred to as the Sample clock rate the rate at which the digital waveforms from device memory are generated The Sample clock is also known as update clock The Sample clock can be exported directly or it can first be divided down by an integer This configuration provides a variable frequency signal related to the waveform sample rate to synchronize other devices to the generation NI does not recommend exporting clocks greater than 20 MHz over PXI_TRIG lt 0 6 gt If you export the divided down Sample clock to another device to synchronize sampling you can also use the Sample clock as the Start trigger for the signal generator Using the divided down Sample clock as the Start trigger begins signal generation at the same place each time relative to the divided down Sample clock This technique is more useful as the divisor becomes larger and while an improvement over using an immediate Start trigger there remains an uncertainty of one Sample clock 3 Note Sample Clock Timebase The 200 400 MHz clock signal from which the internal Sample clock is derived The Sample clock timebase is also known as the board clock When the Sample clock timebase board clock is exported over PXI_TRIG lt 0 6 gt or the PFI 0 and PFI 1 connectors it is always divided down first T
68. al Internal Internal Internal Clock External External External External External External Source CLK IN CLK IN CLK IN CLK IN CLK IN CLK IN Arbitrary PXI_STAR DDC CLK DDC CLK DDC CLK PXI_STAR Waveform PXI only ING ING IN Generation RTSL_ PXI_STAR PXI_STAR PXI_STAR Mode lt 0 7 gt PXI only RTSI_ lt 0 7 gt Calibration Self niFgen_Se niFgen Se niFgen_Se niFgen_Se niFgen_Se niFgen Se niFgen_Se niFgen_Se Calibration 1fCal 1fCal 1fCal 1fCal 1fCal 1fCal 1fCal 1fCal Functions niFgen Re niFgen Re niFgen Re niFgen Re niFgen Re niFgen Re niFgen Re niFgen Re storeLast storeLast storeLast storeLast storeLast storeLast storeLast storeLast ExtCalCon ExtCalCon ExtCalCon ExtCalCon ExtCalCon ExtCalCon ExtCalCon ExtCalCon stants stants stants stants stants stants stants stants Calibration niFgen_ niFgen_ niFgen_ niFgen_ niFgen_ niFgen_ niFgen_ niFgen_ Utility functions functions functions functions functions functions functions functions Functions NI PXle 5450 User Manual 1 10 ni com NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 External niFgen In niFgen In niFgen In niFgen In niFgen In niFgen In niFgen In niFgen In Calibration itExtCal itExtCal itExtCal itExtCal itExtCal itExtCal itExtCal itExtCal Functions and and and and and and and and associated associated associated associated associa
69. al accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follo
70. alliance Declaration of Conformity DoC A DoC is our claim of compliance with the Council of the European Communities using A 1 NI PXle 5450 User Manual Appendix A Technical Support and Professional Services the manufacturer s declaration of conformity This system affords the user protection for electromagnetic compatibility EMC and product safety You can obtain the DoC for your product by visiting ni com certification e Calibration Certificate If your product supports calibration you can obtain the calibration certificate for your product at ni com calibration If you searched ni com and could not find the answers you need contact your local office or NI corporate headquarters Phone numbers for our worldwide offices are listed at the front of this manual You also can visit the Worldwide Offices section of ni com niglobal to access the branch office Web sites which provide up to date contact information support phone numbers email addresses and current events NI PXle 5450 User Manual A 2 ni com
71. ant to generate accurate signals using sampled data an optional lowpass filter must be introduced after the DAC to restrict the National Instruments Corporation 5 5 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals DAC Resolution bandwidth of the output signal to meet the sampling criteria Shannon s Sampling theorem Digital to analog converter DAC resolution is a limiting factor in determining the accuracy of the re creation of an analog waveform from digital samples More details are present in the waveform if the DAC resolution is increased A 3 bit DAC divides its vertical range into eight discrete levels With a vertical range of 10 V the 3 bit DAC cannot generate voltage differences smaller than 1 25 V In comparison a 16 bit DAC with 65 536 discrete levels can generate voltage differences as small as 153 uV The following figure shows the difference between two waveforms The 16 bit waveform looks like a continuous sine wave but if you were to zoom in you would see the discrete steps of 153 uV Both waveforms are composed of discrete voltage steps but the 16 bit version looks much closer to a pure continuous time sine waveform Amplitude V 50 100 150 200 Time us NI PXle 5450 User Manual 5 6 ni com Chapter 5 Signal Generation Fundamentals Impedance Matching When broadband signals are carried on transmission lines of any significant length care must be taken
72. are made at the output of a device under specified conditions 5 12 ni com SINAD ENOB 3 Chapter 5 Signal Generation Fundamentals Signal to noise and distortion ratio SINAD is the ratio of the rms signal amplitude to the rms sum of all other spectral components including the harmonics but excluding DC SINAD is usually expressed in dB Effective number of bits ENOB is another way of specifying signal to noise and distortion ratio SINAD ENOB is calculated using the following formula SINAD 1 76 ENOB 6 02 Note Assumes the full scale of the DAC is utilized The ENOB value is the value of an ideal DAC that is equivalent to the DAC of the device Filtering and Interpolation All NI signal generators use a digital to analog converter DAC to generate the signals or waveforms that eventually appear at the output connector These generated signals have a number of discrete voltage levels dependent on the number of bits in the DAC A digital waveform must be updated at least twice as fast as the bandwidth of the desired analog signal to be accurately generated Shannon s Sampling Theorem Even though the theoretical requirement for National Instruments Corporation 5 13 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals Sample clock f is twice that of the signal bandwidth f images are introduced in the output signal at If nf as shown in the following figure Signal 0 5f
73. are used to measure passband flatness The power meter is an excellent metrology instrument for measuring passband flatness but its performance can be improved by calibrating its frequency response at a low frequency such as 50 kHz with a DMM In other words the DMM measures the amplitude of a 50 kHz tone and the power meter measures the amplitude of all other frequencies with respect to the amplitude of the 50 kHz tone measured by the DMM Passband flatness is important in many applications For example if the sensitivity of a receiver is being tested it is important to know the variation of the amplitude of the test tone as it is swept across the frequency band of interest Some NI signal generators have a Direct Output analog path that has been optimized for passband flatness Others allow you to select a frequency at which the calibrated amplitudes can be finely adjusted to achieve the best amplitude accuracy near the selected frequency National Instruments Corporation 5 1 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals Sample Rate Sample rate is the rate at which digital data is transferred from the memory to the digital to analog converter DAC According to Shannon s Sampling theorem a digital waveform must be updated at least twice as fast as the bandwidth of the signal to be accurately generated Ideally a sample rate many times greater than the frequency of the signal produces accurate waveforms A
74. arker is an event that the signal generator generates in relation to the data bits of a waveform that is generated Up to four bits can be configured to export to any valid destination on the signal generator Level N A Done Event The Done event indicates that the generation of the previous waveform is complete Level Pulse Latched NI PXle 5450 User Manual 2 82 ni com Chapter 2 NI 5450 Overview Marker Events A marker is an event that the device generates in relation to a waveform that is generated The event is configured to occur at the time that a specific location or sample n in the waveform generates on the CH 0 connector If the waveform loops multiple times in a segment the marker generates each time the waveform loops The following figure shows a pulse that represents a waveform sample n that is one Sample clock in width of a waveform being generated on the CH 0 connector The second pulse the Marker event represents the pulse that generates when the corresponding waveform sample n outputs at the CH 0 connector Waveform Sample n Waveform Output on CHO tm2 i tm1 Marker Event gt tm represents the delay in time of the Marker event generated relative to the configured waveform sample n being generated tm2 represents the Marker event pulse width in time NI FGEN takes into account the factors that affect the delays in the Digital and Analog paths in
75. armful interference when the equipment is operated in a commercial environment This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user is required to correct the interference at their own expense Canadian Department of Communications This Class A digital apparatus meets all requirements of the Canadian Interference Causing Equipment Regulations Cet appareil num rique de la classe A respecte toutes les exigences du R glement sur le mat riel brouilleur du Canada Compliance with EU Directives Users in the European Union EU should refer to the Declaration of Conformity DoC for information pertaining to the CE marking Refer to the Declaration of Conformity DoC for this product for any additional regulatory compliance information To obtain the DoC for this product visit ni com certification search by model number or product line and click the appropriate link in the Certification column The CE marking Declaration of Conformity contains important supplementary information and instructions for the user or installer Contents About This Manual edel AE OE OR ER EE NE EE EE IE xiii Related Documentations siese SEE sege KEES oe ESE REG a E E TEA Ee Ese ee xiv Chapter 1 Feature
76. as built in timing and triggering features that can synchronize multiple devices over a backplane timing bus Multiple devices in a modular instrumentation system can share a common Reference clock and synchronize to triggers that are distributed over controlled signal paths that ensure matched propagation PC plug ins with RTS also provide an internal bus that can be accessed by multiple devices Internal routing of these timing signals in PXI and PC plug ins with RTSI eliminate complicated external wiring Standardized timing protocols eliminate incompatibilities giving you the best performance when synchronizing any kind of analog digital or timing measurements Peripheral Component Interconnect PCI is a high performance expansion bus architecture originally developed by Intel to replace ISA and EISA It has achieved widespread acceptance as a standard for PCs and workstations and offers a theoretical maximum transfer rate of 132 Mbytes s Environment Device performance and reliability may be limited at temperatures above the specified operating range For best performance take the following precautions e Ensure that the ambient temperature is within the specifications for the device and is stable 5 C e Follow standard metrology practices e Use a PXI or PXI Express chassis with a well designed cooling system Operating NI PXI and PXI Express signal generators outside the specified operating temperatures can increase
77. assuring that the Marker event appears within one Sample clock of the waveform output Therefore tm is less than one Sample clock period The Marker event pulse width tm2 is at least 150 ns and can be significantly longer than 150 ns for slower Sample clocks You can configure the pulse width by setting the Marker Event Pulse Width property or the NIFGEN_ATTR_MARKER_EVENT_PULSE_WIDTH attribute Instruments commonly have a minimum pulse width specification for a trigger to be registered and trigger pulses of smaller width are ignored The signal generator ensures that a minimum pulse width exists on the Marker event by using a pulse stretching circuit A Sample clock rate of 100 MS s National Instruments Corporation 2 83 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview has a period of 10 ns requiring the pulse to be lengthened for many devices to register the marker as a good trigger pulse Refer to the device specifications for the timing specifications Markers as Trigger Outputs A delay of at least 44 Sample clocks exists between the Start trigger and the analog waveform generation on the output connector Therefore synchronizing the signal generator output signal to other devices with fast trigger response times is accomplished using the Marker event from the signal generator as the trigger source for the other device for more precise alignment to the generating waveform You can do this using the RTSI bus
78. ated onboard memory becomes available you can write a block of waveform data to the streaming waveform in onboard memory EA 1 6 GB Waveform Ouery the Space Available in Streaming Waveform Property to Determine Freed Onboard Memory National Instruments Corporation 2 67 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview 6 Write a block of waveform data Call niFgen Write Waveform VI or the niFgen_WriteWaveform function to write a new block of waveform data to the streaming waveform in onboard memory 16 MB haath arnt 1 6 GB Waveform Write Waveform Data in Blocks 7 Repeat steps 5 and 6 as free space becomes available 16 MB Write Waveform Data in Blocks L H 160 MB 16 MB SR BEA ER Ed enn NI PXle 5450 User Manual 2 68 ni com Chapter 2 NI 5450 Overview Streaming to Multiple Channels To stream data to multiple channels you must provide data that is interleaved For example to stream I16 data to two channels you must interleave channel 0 and channel 1 samples so the first sample will go to channel 0 the second to channel 1 the third to channel 0 and so on You cannot stream to two or more channels with individual non interleaved writes for each channel Average Performance Rates The following tables list the average data rates possible for PXI PCI and P
79. ating impedance Zo characteristic impedance The resulting voltage waveform is distorted by the asymptotic decay of the reflected pulse as shown exaggerated for visual effect Impedance discontinuities of smaller magnitude and or duration have correspondingly smaller effects Also displayed is the waveform that results when a cable of matched impedance 75 Q is used NI PXle 5450 User Manual 5 8 ni com Chapter 5 Signal Generation Fundamentals Mismatch Uncertainty Impedance matching is also important for preserving the absolute delivered power from a device The accuracy with which power can be delivered is limited by mismatch error The mismatch error in a z g system can be shown to be bounded by 2 2 bf lt mismatch error lt EIN Te 1 Cl Fe where Tz load reflection coefficient Tg generator reflection coefficient The denominator term represents mismatch uncertainty which is a fundamental limit to the power transfer accuracy that can be achieved across a mismatched junction Resistive Matching Signal generators with low high source impedance can be matched with a resistor placed in series shunt such that the total source impedance admittance is matched to the cable characteristic impedance admittance Signal generators that are not capable of driving the cable impedance directly can be coupled through a matching L pad In this case the signal generator sees an approximately 500 Q load while the sourc
80. ay Be sure that the string is null terminated Parameter Passing By default Visual C passes parameters by value Remember to pass pointers to variables when you need to pass by address Creating an Application with Visual Basic This topic assumes that you are using Visual Basic to manage your code development and that you are familiar with the ADE To develop an NI FGEN application in Visual Basic follow these general steps 1 Open an existing or new Visual Basic project 2 Create the following files which are necessary for your application and add them to your project rm form definition and event handling code e optional bas Visual Basic generic code module e optional cls Visual Basic class module 3 Adda reference to the National Instruments Function Generator library NI FGEN which is part of niFgen_32 d11 by selecting 4 8 ni com Chapter 4 Programming Project References and then National Instruments Function Generator yl Note If you do not see the NI FGEN library listed there click Browse and locate niFGEN_32 d11 in the directory listed in the NI FGEN Instrument Driver Readme 4 Use the Object Browser lt F2 gt to find function prototypes and constants 5 Add NI FGEN function calls to your application 6 Run your application by clicking Run Start NI FGEN Tutorial Example Programs NI FGEN ships with several examples that demonstrate basic signal generator applicatio
81. base when M 22 and the Reference clock can be exported to the PXI_Trig lines The PXI standards allow for devices to route signals to other devices in your PXI Express chassis to enhance device to device synchronization Refer to the chassis documentation for specifications to ensure the reference signal is within tolerance You must configure the device to export the desired clock to the PXI_Trig line Refer to niFgen Export Signal VI or the niFgen_ExportSignal function for more information about configuring the destinations for the desired clock signal Onboard Memory The NI 5450 signal generator uses an onboard memory that is 16 bits wide The minimum standard memory size for the NI 5450 is 128 MB With the minimum standard memory size you can store very long waveforms on the device and obtain reliable waveform generation at full sample rate of 400 MS s The NI 5450 also comes with higher memory options of 512 MB or 2 GB The onboard memory is a single large memory area per channel that stores both waveforms and sequence instructions to generate the waveforms The instructions for a complicated sequence can occupy a significant portion of memory The architecture of the NI 5450 allows you to load multiple waveforms and multiple sequence instructions into the memory The following diagram illustrates NI 5450 memory allocation A number of waveforms are stored in the onboard memory ranging from 1 to n there are also a number of sequen
82. be faster than transferring one 160 MB block 9 Tip NI FGEN reguires the guotient of the waveform size divided by the data transfer block size to be an integer value If the waveform size is not an integer multiple of the block size change either the waveform size or the block size A fractional number of data blocks in the waveform returns an error message 4 Call the niFgen_InitiateGeneration function to begin the waveform generation 5 Use the NIFGEN_ATTR_STREAMING_SPACE_AVAILABLE_IN_WAVEFORM attribute to determine how much of the streaming waveform is free for writing new data NI PXle 5450 User Manual 4 30 ni com Chapter 4 Programming EN ATTR STREAMING SPACE AVAILABLE IN WAVEFORM attribute B Note The NIFG specifies the total a generation this ava mount of space available in the streaming waveform During ilable space may be in multiple locations with for example part of the available space at the end of the streaming waveform and the rest at the beginning In this situation writing a block of waveform data the size of the total space available in the streaming waveform causes NI FGEN to return an error as NI FGEN will not wrap the data from the end of the waveform to the beginning and cannot write data past the end of the waveform buffer To avoid writing data past the end of the waveform write new data to the waveform in a fixed size that is an integer divisor of the total size of the streaming
83. bitraryWaveform or the Arbitrary Waveform examples for CVI 1 Call the niFgen ConfigureOutputMode function with the outputMode parameter to NIFGEN_VAL_OUTPUT_ARB 2 Optional Call the niFgen_ClearArbWaveform function This clears any previously created arbitrary waveforms from the signal generator memory 3 Call one of the niFgen Create Waveform functions niFgen_CreateWaveformF64 niFgen_CreateWaveformI16 niFgen CreateWaveformComplexF64 niFgen_CreateWaveformFromFileI16 or niFgen_CreateWaveformFromFileHws The function you choose creates a waveform the size and type of the data you choose 4 Call the nifgen_ConfigureArbWaveform function to configure the gain and offset of the waveform Configure Arbitrary Sequence Mode You can use Arbitrary Sequence mode to load multiple waveforms in the onboard memory of the signal generator LabVIEW Example The procedure below provides the basic steps required to configure Arbitrary Sequence mode For more detailed examples of the use of Arbitrary Sequence mode in LabVIEW refer to the Fgen Basic Arb Sequence vi or the Fgen Arbitrary Sequence vi examples for LabVIEW 1 Call the niFgen Configure Output Mode VI with Output Mode set to Arbitrary Waveform 2 Optional Call the niFgen Clear Arbitrary Memory VI to clear any previously created arbitrary waveforms sequences and scripts from the signal generator memory 4 14 ni com Chapter 4 Programming Choose one of the fol
84. by directly driving the DAC and all waveform generation operations on the device The following table shows the valid NI FGEN property or attribute value combinations that can be used to configure the clock settings for an internal Sample clock an external Sample clock or a Reference clock The term Update clock is synonymous with Sample clock Sample Clock PLL Reference Source Clock Mode Clock Source OnboardClk NIFGEN VAL HIGH None default default RESOLUTION F 5 PXI_CLK10 ClkIn NIFGEN_VAL_ None default AUTOMATIC default PXI_CLK10 ClkIn ClkIn Not Applicable Not Applicable These column headings refer to NI FGEN properties The attributes that correspond to these properties are NIFGEN_ATTR_SAMPLE_CLOCK_SOURCE NIFGEN_ATTR_CLOCK_MODE and NIFGEN_ATTR_REFERENCE_CLOCK_SOURCE The values in the columns represent the values that can be set on these properties or attributes Settings that line up horizontally show valid combinations of the NI FGEN settings 2 36 ni com Chapter 2 NI 5450 Overview Internal Sample Clock The NI 5450 can derive a Sample clock from its main internal timing source the Sample clock timebase The signal generator provides a high precision 400 MHz oscillator clock source for the Sample clock timebase The following figure shows the NI 5450 internal Sample clock Source path Sample Cloc
85. ce instructions ranging in number from 1 to m The values of n and m depend on the waveform and instructions configured and are ultimately limited by the amount of memory Sequence Sequence Sequence eee Instructions Instructions eee Instructions 1 2 n Memory Waveform Waveform Waveform Free 1 2 m NI PXle 5450 User Manual 2 44 ni com Chapter 2 NI 5450 Overview The following tables list the types of information that are used to make up the instructions that are saved to memory You can store the instructions for multiple sequences to the onboard memory ahead of time and generate them later allowing for quick reconfiguration times between tests There are two example sequences Sequence represents the instructions for a sequence containing a maximum number of segments k Sequence m is an example of a sequence containing 8 segments Each sequence downloads different waveforms to the onboard memory and uses various looping and Marker placement options to construct the resulting waveform Sequence 1 Burst Trigger Mode Sequence Segment Waveform Number of Loops Marker Placement 1 1 1 0 2 5 14 100 3 17 1 1 4 12 18 045 10 000 5 12 64 000 12 6 34 64 000 0 k 15 20 10 000 Sequence m Stepped Trigger Mode Sequence Segment Waveform Number of Loops Marker Placement 1 1 1 0 2 2 340 4 3 35 1 1 4 2 10 0 5 340 5 10 000 6 34 64 000 0
86. channels at the same time Writing Data On the NI 5450 data can either be written to channel 0 and 1 independently to I and Q independently or to both channels simultaneously National Instruments Corporation 2 19 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Tip The flexibility to write waveform data to channels either separately or simultaneously Ss is especially useful when configuring applications for I Q generation To write waveform data to an individual channel begin by allocating space for waveform data by calling the niFgen Allocate Waveform or niFgen Allocate Named Waveform VI or the niFgen AllocateWaveform or niFgen_AllocateNamedWaveform function Once you have allocated the waveform data call the appropriate niFgen Write Waveform poly VI or one of the niFgen Write Waveform functions with the Channel Name parameter set to 0 or 1 and the Waveform Name or waveformHandle parameter set to the name of the waveform previously allocated You can repeat these steps to write waveform data to another channel To write waveform data to both channels at once you must first interleave the data Once the data is interleaved call the niFgen Write Waveform poly VI or one of the niFgen Write Waveform functions with the Channel parameter set to 0 1 Interleaved Waveform Data In order to write data to multiple channels on the same device simultaneously the data must be interleaved Interleaved sampl
87. chassis for the trigger lines The RTSI features of NI signal generators is implemented on this sub bus The RTSI triggers lt 0 6 gt are implemented on PXI_Trig lt 0 6 gt and the RTSI clock is routed on PXI_Trig7 National Instruments Corporation 3 5 NI PXle 5450 User Manual Chapter 3 Integration and System Considerations System Reference Clock PXI GLK10 PFI Lines The PXI chassis supplies the PXI 10 MHz system Reference clock signal PXI_CLK10 independently to each peripheral slot An independent buffer drives the clock signal to each peripheral slot The buffer has a source impedance matched to the backplane and a skew ranging from less than 1 ns to better than 250 ps between slots You can use this common Reference clock signal to synchronize multiple devices in a measurement or control system You can drive PXI_CLK10 from an external source through the PXI_CLK10_IN pin on the P2 connector of the PXI star trigger slot which is slot 2 Sourcing an external clock on this pin automatically disables the 10 MHz source on the backplane You can synchronize multiple chassis that have connectors on the back panel for 10 MHz reference in and 10 MHz reference out Refer to your PXI chassis documentation for more information N Caution PFI lines are multipurpose programmable function input outputs These lines serve as connections to virtually all internal timing signals NI signal generators have up to six digital lines that can
88. cifications for conditions National Instruments Corporation NI PXle 5450 User Manual NI 5450 Overview The NI 5450 is a 400 MS s 16 bit differential I Q generator for the PXI Express platform with the following features e Onboard signal processing OSP with 120 MHz of baseband VO bandwidth flatness correction and interpolation e 16 bit resolution output two channels differential output e Differential output amplitude with a maximum of 1 0 Vr pk into a 100 Q differential load e 50 Q output impedance 100 Q differential output impedance and output attenuation levels from 0 to 3 dB e High Resolution internal clocking e External clocking options e PLL synchronization to external clocks or to PXI clock e TCIk synchronization e Sample rate up to 400 MS s e Up to 2 GB of onboard waveform memory e Waveform linking and looping for arbitrary waveform generation e Digital gain e 2 bidirectional PFI lines for importing triggers and exporting events e PXI trigger lines All NI 5450 devices follow industry standard Plug and Play specifications for the PXI Express bus and offer seamless integration with compliant systems National Instruments Corporation 2 1 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Front Panel The following figure shows the NI PXIe 5450 front panel This front panel has two SMB connectors and six SMA connectors NATIONAL INSTRUMENTS NI PXle 5450 400 MS s I Q Signal
89. connector can accept a Reference clock from an external source and phase lock the internal clock of the signal generator to this external Reference clock Refer to the device specifications for the allowable Reference clock frequencies and signal characteristics National Instruments Corporation 2 5 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview The Reference clock uses the internal clock by default Call the niFgen Configure Reference Clock VI or the niFgen_ConfigureReferenceClock function to configure the Reference clock source When configuring an external Reference clock you must configure the external Reference clock frequency if it is different from the 10 MHz default setting Set the Reference clock frequency with the niFgen Configure Reference Clock VI or the niFgen_ConfigureReferenceClock function 3 Note You also can phase lock the signal generator to other NI devices using the common PXI 10 MHz backplane clock on PXI devices 3 External Sample Clock Input In addition to phase locking the CLK IN connector also can receive an external Sample clock Refer to the device specifications for the allowable external Sample clock frequencies and signal characteristics Tip When configuring an external Sample clock set the sample rate to the exact frequency you are using to avoid data errors Set the sample rate by calling the niFgen Set Sample Rate VI or niFgen_ConfigureSampleRate function NI PXle 5450 User Manual
90. d PXI Express signal generators are designed to operate at shock up to 30 g 11 ms half sine It is specified to withstand shock up to 50 g 11 ms half sine when not operating shipping storage NI PXI and PXI Express signal generators are designed to withstand total random vibration of 0 31 g operational and 2 46 g ms non operational per TEC 68 2 64 3 2 ni com Chapter 3 Integration and System Considerations PXI PXI Express Chassis Cooling Not all PXI or PXI Express chassis provide the same cooling When selecting a PXI or PXI Express chassis consideration should be given to providing adequate airflow for high power and sensitive devices such as NI signal generators NI PXI and PXI Express signal generators are high precision instruments and may be sensitive to interference from other electronic devices To optimize the accuracy and performance of the device you may need to locate the device in a slot away from devices with power supplies and other noisy circuitry The device may also be sensitive to heat generated by high power products in neighboring slots When possible consider locating the device away from high power devices to optimize cooling PXI Modules PCI eXtensions for Instrumentation PXI modular instrumentation delivers a PC based standardized high performance measurement and automation system PXI combines the high speed PCI bus with integrated timing and triggering designed specifically for measu
91. d call the niFgen Write Waveform VI multiple times The data is appended sequentially A computer can allocate smaller blocks of a large waveform faster than allocating a single large contiguous block in memory Depending on the amount of RAM on the computer transferring ten 16 MB blocks may be faster than transferring one 160 MB block ag Tip NI FGEN requires the quotient of the waveform size divided by the data transfer block size to be an integer value If the waveform size is not an integer multiple of the block size change either the waveform size or the block size A fractional number of data blocks in the waveform returns an error message 4 Call the niFgen Initiate Generation VI to begin the waveform generation 5 Use the Space Available in Streaming Waveform property to determine how much of the streaming waveform is free for writing new data yl Note The Space Available in Streaming Waveform property specifies the total amount of space available in the streaming waveform During generation this available space may be in multiple locations with for example part of the available space at the end of the streaming waveform and the rest at the beginning In this situation writing a block of waveform data the size of the total space available in the streaming waveform causes NI FGEN to return an error as NI FGEN will not wrap the data from the end of the waveform to the beginning and cannot write data past the end of the waveform buf
92. d waiting for a trigger Green The device has received a trigger Also indicates that the device is generating a waveform Red The device has detected an error NI FGEN must access the device to determine the cause of the error The LED remains red until the error condition is removed Errors might include unlocked PLLs or an over temperature condition NI PXle 5450 User Manual 2 8 ni com Chapter 2 NI 5450 Overview Power Up and Reset Conditions The signal generator is in the following state from the time at which the computer begins to power up until the operating system is fully booted and NI FGEN is loaded The CH 0 and CH 1 differential output connectors are disabled and each has 50 Q impedance to ground This impedance is the same as its previous setting before the device was powered down The output voltage amplitude of this connector is 0 V The CLK IN connector has high impedance to ground PFI 0 and PFI 1 are tristated and have a 10 kQ impedance to ground The CLK OUT connector is tristated and has a high impedance to ground PXI trigger lines are tristated and floating After the operating system is fully booted and NI FGEN is loaded or when you perform a hard reset to the device directly from MAX or using NI FGEN the signal generator is in the following state National Instruments Corporation CH 0 and CH 1 output is enabled CH 0 and CH 1 output at
93. de you can create up to four markers for each waveform LabVIEW Example 1 To create markers in Script mode refer to Common Scripting Use Cases in the NI Signal Generators Help 2 Export the marker event by calling the niFgen Export Signal VI Set Signal to NIFGEN VAL MARKER EVENT and set Signal Identifier to the name of the marker to export National Instruments Corporation 4 27 NI PXle 5450 User Manual Chapter 4 Programming C Example 1 To create markers in Script mode refer to refer to Common Scripting Use Case 2 Export the marker event by calling the niFgen ExportSignal function Set the signal parameter to NIFGEN_VAL_MARKER_EVENT and the signalldentifier parameter to the name of the marker to export Creating a Data Marker Event To create and export a Data Marker event complete the following steps LabVIEW Example 1 Specify a data bit number using the Data Marker Event Bit Number property 2 Set the output polarity of the data marker event using the Data Marker Event Level Polarity property 3 To export the data marker use the niFgen Export Signal VI To determine all possible signal routes for your device refer to Signal Routing ays Note When exporting data markers you must specify the signal identifier for the data marker using the niFgen Export Signal VI C Example 1 Specify a data bit number using the NIFGEN ATTR DATA MARKER EVENT DATA BIT NU
94. e none none none none none Source External External External External External External External External CLK IN CLK IN CLK IN CLK IN CLK IN CLK IN CLK IN CLK IN PXI PXI PXI PXI PXI PXI PXI PXI 10 MHz 10 MHz 10 MHz 10 MHz 10 MHz 10 MHz 10 MHz 10 MHz clock PXI clock PXI clock PXI clock PXI clock clock clock clock only only only only RTSI_7 RTSI_7 RTSI_7 RTSI_7 RTSI RTSI RTSI RTSI clock PCI clock PCI clock PCI clock PCI only only only only Onboard Onboard Onboard Onboard PCI only PCI only PCI only PCI only Reference 5 MHz to 5 MHz to 5 MHz to 5 MHz to 5 MHz to 5 MHz to 5 MHz to 1 to Clock 20 MHz in 20 MHz in 20 MHz in 20 MHz in 20 MHz in 20 MHz in 20 MHz in 100 MHz in Freguency 1 MHz 1 MHz 1 MHz 1 MHz 1 MHz 1 MHz 1 MHz 1 MHz steps steps steps steps steps steps steps steps 102 MHzto 200 MHz in 2 MHz steps 204 MHz to 400 MHz in 4 MHz steps Clock Mode Divide Divide Divide Divide Divide High Arbitrary Down Down Down Down Down Resolution Waveform High High High High High Automatic Generation Resolution Resolution Resolution Resolution Resolution Mode Automatic Automatic Automatic Automatic Automatic National Instruments Corporation 1 9 NI PXle 5450 User Manual NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Sample Internal Internal Intern
95. e if the output of the device terminates into a balanced 50 Q load with flatness correction disabled the maximum output levels are 0 5 V while the maximum output levels are 1 0 when the device terminates into a high impedance load HiZ This difference is illustrated in the following figure NI 5450 NI 5450 0 5 V 1 0 V 50 Q Load High Impedance Load If the output terminates into any other load the levels are defined by the following formula Vou ER ORLt Ro 1x2 V where Vi is the maximum peak output voltage level Ri is the load impedance in ohms Ro is the output impedance of the module in ohms Sy Note For loads less than 50 Q load impedance compensation supports only combinations of gain and load impedance that meet the previous V out equation Set the amplitude of the generated output signal in terms of peak voltage by setting the gain value NI FGEN calculates and sets the correct amount of attenuation required for the desired gain value Configure the output signal NI PXle 5450 User Manual 2 4 ni com 3 CLK IN Connector A Chapter 2 NI 5450 Overview amplitude by calling the Arbitrary Waveform Gain property or NIFGEN_ATTR_ARB_GAIN attribute Load Impedance Compensation The NI 5450 has the ability to configure the output signal amplitude based on a user configured load impedance setting This capability is desirable when you use the NI 5450 with loads that are between 0 and a high
96. e complete transfer would occur using four separate DMA transfers If you modify the data transfer block size to 8 MS 16 MB for example the data transfer is more efficient and is instead accomplished in a single transfer Configure advanced streaming properties by calling the Maximum In Flight Read Requests PCI DMA Optimization Enabled or Preferred Packet Size property or the NIFGEN_ATTR_DATA_TRANSFER_MAXIMUM_IN_FLIGHT_READS NIFGEN_ATTR_DATA_TRANSFER_PCI_DMA_OPTIMIZATIONS or NIFGEN_ATTR_DATA_TRANSFER_PREFERRED_PACKET_SIZE attributes Optimize the bus bandwidth usage for multi device streaming applications by calling the Maximum Bandwidth property or the NIFGEN_ATTR_DATA_TRANSFER_MAXIMUM_BANDWIDTH attribute When streaming from hard drives consider the hard drive speed for maximum sustainable rates Laptop hard drives typically have a data transfer rate of 25 to 30 MB s Desktop hard drives often can meet 55 to 70 MB s Transfer rates from hard drives can vary for a number of reasons including where the data is physically stored on the hard drive and how much data is stored Storing your waveform files on a fairly empty defragmented hard drive may help increase performance Consider using a redundant array of independent disks RAID configuration to utilize striping to increase data transfer rates from disk When using 18 slot PXI chassis install the signal generator used for streaming in the fir
97. e for all subsequent instructions until the clear instruction is called or the trigger is reset after being used in the wait repeat end repeat or if instructions Types of Triggers A trigger is an external stimulus that initiates one or more device functions Trigger stimuli include digital edges software functions and analog levels You can trigger your NI signal generator with one of the following types of triggers e Edge e Level e Software 3 Note Individual triggers may not support all the trigger types listed here National Instruments Corporation 2 73 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Edge Trigger A digital signal has two discrete levels a high level and a low level When the signal transitions from high to low or from low to high a digital edge is created There are two types of edges rising which occurs when the signal transitions from low level to high level and falling which occurs with a transition from high level to low level Triggers configured to act on a rising or falling edge of a digital signal are called edge triggers As the following figure shows an edge trigger could be configured to occur either at the place labeled Falling Edge of Signal or at Rising Edge of Signal High Level Falling Edge of Signal Rising Edge of Signal Low Level Trigger Sources NI PXle 5450 User Manual Level Trigger You can configure certain trigge
98. e impedance presented to the cable is 50 Q as shown in the following figure Characteristic Impedance 50 Q 500 Q 50 Q 4752 sl To DAC Coaxial L Pad Cable Input National Instruments Corporation 5 9 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals High frequency components and layout techniques should be used throughout to minimize parasitic effects Output Attenuation NI PXle 5450 User Manual Output attenuation is a method of controlling the output voltage level of the signal being generated NI signal generators typically generate signals with a digital to analog converter DAC that has an output voltage range of 5 0 V to 5 0 V with a number of bits of resolution This signal is applied to an attenuator that controls the output voltage of the signal source By attenuating the DAC output signal you keep the dynamic range of the DAC that is you do not lose any bits from the digital representation of the signal because the attenuation is done after the DAC and not before it For example if a DAC with a range of 5 0 V to 5 0 V and a resolution of 12 bits with each bit corresponding to 2 44 mV 5 0 5 0 2412 does not use output attenuation and the desired signal is 2 0 V pk pk 1 0 V to 1 0 V waveform values can be generated with the DAC that only use of the DAC range The resolution of each digital bit is still 2 44 mV However if the sa
99. eaming The allocated memory known as the streaming waveform serves as a buffer for the streaming 2 64 ni com Chapter 2 NI 5450 Overview process The size of the waveform you wish to stream must be evenly divisible by the amount of onboard memory allocated for streaming to prevent the streaming waveform from being overwritten before it has generated 160 MB Allocated EE 160 MB FRAY INE EI ace Memory Used for a i NS Additional Waveforms and Script Instructions 2 Identify the streaming waveform Set the Streaming Waveform Handle property or the NIFGEN_ATTR_STREAMING_WAVEFORM_HANDLE attribute to the waveform handle returned in step 1 Setting this property or attribute ensures that none of your streaming data is overwritten before it is generated NI FGEN monitors your progress to ensure that you write fresh data fast enough to keep up with the generation If your application fails to keep up or attempts to write fresh data over data that has not been generated NI FGEN returns an error nanan 1 6 GB Waveform Set the Streaming Waveform Handle Property to Identify the Waveform for Streaming 160 MB Pd MA LAMA AA MAA National Instruments Corporation 2 65 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview 3 Fill the streaming waveform with initial data Call the niFgen Write Waveform VI or the niFgen_WriteWaveform function
100. ebase source by calling the Sample Clock Timebase Source property or the NIFGEN_ATTR_SAMPLE_CLOCK_TIMEBASE_SOURCE attribute You can set the Sample clock timebase rate with the Sample Clock Timebase Rate property or the NIFGEN_ATTR_SAMPLE_CLOCK_TIMEBASE_RATE attribute You can export the Sample clock timebase to a terminal configured by the Sample Clock Timebase Export Output Terminal property or the NIFGEN_ATTR_EXPORTED_SAMPLE_CLOCK_TIMEBASE_OUTPUT_ TERMINAL attribute 3 Note Refer to the device specifications for the allowable voltages signal types and clocks that you can use for an external Sample clock timebase National Instruments Corporation 2 41 NI PXIe 5450 User Manual Chapter 2 NI 5450 Overview Exporting Clocks The NI 5450 provides resources for exporting your clocks and multiple destinations for routing Reference Clock le Clock Timeb Timebase M Sample Clock Timebase Divide M imebase Sample Clock Sample Clock Sample Clock K Divide K CLK OUT The following table shows the available clock signals that can be routed to devices external to the signal generator and the destination options Sy Note The PFI outputs have a bandwidth of 200 MHz The PXI Trigger lines have a bandwidth of lt 20 MHz The following table shows the software limits of the export destinations Clock to be Ex
101. ee ee se ee ee ee ee ke 2 17 Filtering Effects We ee ve ee eo ee RE ease Oe Ve ee ee ee 2 17 Output Enable se sheila leat ae ee eg GR 2 18 Multichannel Configuration 00 0 sesse se se ee ek Ge Re Se ee ee Re ee ee ee 2 19 Configuring Channels for OSP oo ee se ee ee Se ee ee ee 2 19 National Instruments Corporation vii NI PXle 5450 User Manual Contents Multichannel Waveform Allocation 0 0 eee se se ke Se ee Se Re ee ee 2 19 Writing Data RR RE EE RE BE RE 2 19 Interleaved Waveform Data sesse esse sesse see se ee se ee Se ee ee 2 20 Onboard Signal Processing OSP ees se se ee ee Ge ee ee ee ke ed ke 2 21 Onboard Signal Processing Component 1 0 0 0 ce sesse se ke ee ke 2 21 VQ SE EE EE tired EE RIIAS 2 22 Prefilter G ER EE EE OO EE 2 22 wll det AR RE RE EE 2 22 FIR Filter Types ii tese iese eis states aana 2 23 FIR Filter Type Flat tese vele see ese ee Des ends gese did 2 24 FIR Filter Type Raised Coin eee see se ee 2 25 FIR Filter Type Root Raised Cosine eee 2 26 Filtering and Interpolation ee see ee ee ee 2 27 Writing VQ Data cscs RE EE OE ER ON 2 27 Basic Onboard Signal Processing Properties 2 27 OSP ER EE RE EE 2 21 OSP Enabled eiea sd ee n be ee sag ve ee 2 28 Data Processing Mode esse sesse ee ee Se ee Re ee ee 2 28 IQ Er EEN ees 2 28 Frequency SBIfE sue ese SERE Reg Gee EES Ge ROES Gegee Gee Rae Ke oge Eie 2 29 FIR Filter Ty SEE EE EE EE 2 30 Common Onboard Signal Processing Applicati
102. eed bandwidth to the PCI Express bus You can configure the NI PXI Express signal generator to limit its use of the PCI Express bus leaving bandwidth for other devices that are more susceptible to short term bursts of traffic on a shared PCI Express link You may also be able improve the performance of your device based on your system configuration The following table lists the properties and attributes that allow you to modify the way that the signal generator uses the PXI Express bus LabVIEW Property C C Attribute Purpose Maximum Bandwidth NIFGEN_ATTR_DATA_TRANSFER Allows you to optimize bus _MAXIMUM_BANDWIDTH bandwidth usage for multi device streaming applications National Instruments Corporation 2 71 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview LabVIEW Property C C Attribute Purpose Maximum In Flight Read Requests NIFGEN_ATTR_DATA_TRANSFER _MAXIMUM_IN_FLIGHT_READ REQUESTS Allows you to specify based on the requirements of your application the maximum number of in flight read requests for data transfers Preferred Packet Size NIFGEN ATTR DATA TRANSFER _PREFERRED PACKET SIZE Allows you to configure based on the reguirements of your system the preferred size of the data field in the PCI Express data transfer packet Triggering NI PXle 5450 User Manual Triggers are signals that cause the signal
103. eforms are written to your device call the niFgen Write Script VI to write the script s containing the generation instructions to be executed The script you write can manage waveform generation based on multiple waveforms and triggers For example you could download waveforms A B C and D into device memory You could then write a script that would wait for a trigger to initiate generation and upon receiving this trigger generate waveform A three times with a marker at position 16 each time and finally generate waveforms B C and D twice BCDBCD The following is the script of this example script myFirstScript wait until scriptTrigger0 repeat 3 generate waveformA marker0 16 end repeat repeat 2 generate waveformB generate waveformC generate waveformD end repeat end script 4 Optional You can write multiple scripts that exist simultaneously on your device If you write multiple scripts to your device you must National Instruments Corporation 4 17 NI PXle 5450 User Manual Chapter 4 Programming NI PXle 5450 User Manual select the one you wish to execute by setting the Script to Generate property C Example The procedure below provides the basic steps required to configure Script mode To see a more detailed example of the use of Script mode in C refer to the ArbitraryScript example for CVI 1 Call the niFgen configureOutputMode function with outputMode set to NTFGEN VAL OUTPUT FUNC 2 Wri
104. eout or performance issue with your module or if you are not certain that the application ran select Start All Programs National Instruments MXI 3 MXI 3 Optimization to run the application If you continue to have initialization or performance issues refer to the MXI 3 documentation at Start All Programs National Instruments MXI 3 or visit NI Technical Support at ni com support MXI 4 and MXI Express Optimization Optimization for MXI 4 and MXI Express are performed automatically by the hardware National Instruments Corporation 3 7 NI PXle 5450 User Manual Programming Programming State Model In this topic the word property when not referring to a specific property refers to both properties in LabVIEW and attributes in C or CVI The NI FGEN programming model has three main states Idle Committed and Generating as shown in the following figure Init Clase Set OTF Attribute Set tset Load Waveform Attribute or Seguente Set OTF Attribute Initiate Commit Generation Running Committed OM se Set Mor DTF Abart Attribute Generation Idle You can program all session properties in the Idle state However when in the Idle state the properties may not have been applied to the device yet so the device hardware configuration may not match the session property values the device remains configured as it was the last time a session was committed If the computer
105. er to VI FALSE the function initializes the device without performing an ID query 4 10 ni com Chapter 4 Programming e The resetDevice parameter allows you to reset the signal generator during initialization e The vi parameter returns a handle that when passed to subsequent functions allows you to communicate with the signal generator throughout your session Configuration Once you have opened a session to your signal generator you need to configure the session to generate the signals you desire for your application If you are using a multichannel device you must configure channels immediately after initializing and before configuring any other feature of the device When configuring the output mode of your device you can choose to generate a standard waveform an arbitrary waveform an arbitrary sequence a frequency list or a script Refer to the Features Supported topic for your device for more information about the type of output modes it supports 3 Note If your application requires triggers clocking or exported signals you must configure them before waveform generation begins Refer to the Features section for more information on configuring your signal generator Configure Channels If you want to configure a multichannel signal generator to generate data on more than one channel you must configure the channels to be used B Note If you are not using a multichannel signal generator or if you are only concerned wi
106. erform this procedure LabVIEW Example 1 Call the niFgen Configure Sample Clock Source VI with Source set to OnboardClock Perform the following step only if your application is configured for Arbitrary Waveform or Arbitrary Sequence output mode 2 Call the niFgen Configure Clock Mode VI with Clock Mode set to the clock mode required for your application C Example 1 Call the niFgen ConfigureSampleClockSource function with the sampleClockSource parameter set to OnboardClock Perform the following step only if your application is configured for Arbitrary Waveform or Arbitrary Sequence output mode 2 Call the niFgen ConfigureClockMode function with the clockMode parameter set to the clock mode required for your application National Instruments Corporation 4 23 NI PXle 5450 User Manual Chapter 4 Programming Configuring an External Sample Clock Some NI signal generators can accept an external clock to directly drive the Sample clock When using an external Sample clock the frequency stability and accuracy of the Sample clock is determined by the external Sample clock provided LabVIEW Example 1 Call the niFgen Configure Sample Clock Source VI with the Source set to an external location Perform the following step if your application is configured for Arbitrary Waveform Arbitrary Sequence or Script output mode 2 Call the niFgen Set Sample Rate VI with the Sample Rate set to the frequency of t
107. es prioritize samples before channels such that the array lists the first sample from every channel in the task then the second sample from every channel up to the last sample from every channel 3 Note When interleaved waveform data is allocated one sample includes data on multiple channels Therefore the allocation size of interleaved data in bytes is equal to number of channels being used x the number of samples on each channel x 2 NI PXle 5450 User Manual Channel 0 Sample 1 Channel 1 Sample 1 Channel 0 Sample 2 Channel 1 Sample 2 Channel 0 Sample N Channel 1 Sample N 2 20 ni com Chapter 2 NI 5450 Overview Onboard Signal Processing OSP The onboard signal processing OSP block is a general purpose block of digital signal processing components that can be used to modify the data pulled from waveform memory during generation The OSP block can be used for the following common applications Arbitrary Waveform Generation Baseband Interpolation Baseband I Q Interpolation Onboard Signal Processing Components The following figure shows the block diagram of the OSP block Waveform Memory Output Engine DAC DAC Q gt Onboard Signal Processing Pre Filter Pre Filter Filtering Digital Gain Offset gt and Interpolation gt Gain gt
108. fer To National Instruments Corporation 4 29 NI PXle 5450 User Manual Chapter 4 Programming avoid writing data past the end of the waveform write new data to the waveform in a fixed size that is an integer divisor of the total size of the streaming waveform 6 Call the niFgen Write Waveform VI to write a new block of waveform data to the streaming waveform in onboard memory Repeat the process of monitoring the available memory and writing waveform data in blocks as free space becomes available C Example The procedure below provides the basic steps required to configure streaming For a more detailed example of the use of streaming in C refer to the ArbitraryWaveformStreaming prj example for CVI 1 CalltheniFfgen_AllocateWaveform function to specify the amount of onboard memory to reserve for streaming 2 Set the NIFGEN ATTR STREAMING WAVEFORM HANDLE attribute to the waveform handle returned in Step 1 3 Call the niFgen_WriteWaveform function to write the first part of the waveform data to the streaming waveform in onboard memory a Tip When transferring large blocks of waveform data break the data into smaller blocks and call the niFgen_WriteWaveform function multiple times The data is appended sequentially A computer can allocate smaller blocks of a large waveform faster than allocating a single large contiguous block in memory Depending on the amount of RAM on the computer transferring ten 16 MB blocks may
109. filter Analog Filter 3 has a much higher 3 dB point than the first two analog filters Because of the higher 3 dB point the filter is very nearly flat in the passband 0 to 0 43f Analog Filter 3 does not filter the images produced at f and 2f at all but this shortcoming can be alleviated with a digital interpolation filter 0 5f f 2 3f At To ease the requirements of the analog filter and to get more output bandwidth NI signal generators use a halfband digital filter to interpolate one three or seven samples between every two waveform samples at two times four times and eight times the sample frequency f Also the DAC operates at an effective sampling rate that is two times 2f four times 4f and eight times 8f the sample frequency specifically the rate at which the data is clocked from the memory into the DAC In the following figure the two times interpolating filter is used and the effective sample rate of the DAC is 2f The images at f f are no longer an issue and the images are now at I2f fl National Instruments Corporation 5 15 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals OS fg 2 3f Af Now Analog Filter 2 can easily filter out all the images due to the digital generation of the signal This behavior is seen in the frequency domain representation in the previous figure and in the time domain representation in the following figure
110. following conventions are used in this manual Angle brackets that contain numbers separated by an ellipsis represent a range of values associated with a bit or signal name for example AO lt 3 0 gt Square brackets enclose optional items for example response The symbol leads you through nested menu items and dialog box options to a final action The sequence File Page Setup Options directs you to pull down the File menu select the Page Setup item and select Options from the last dialog box The symbol indicates that the following text applies only to a specific product a specific operating system or a specific software version This icon denotes a tip which alerts you to advisory information This icon denotes a note which alerts you to important information This icon denotes a caution which advises you of precautions to take to avoid injury data loss or a system crash When this symbol is marked on a product refer to the Read Me First Safety and Radio Frequency Interference document included with the device for information about precautions to take Bold text denotes items that you must select or click in the software such as menu items and dialog box options Bold text also denotes parameter names Italic text denotes variables emphasis a cross reference or an introduction to a key concept Italic text also denotes text that is a placeholder for a word or value that you must supply National Ins
111. form an action such as starting or stopping a generation operation Triggers can be internal software generated or external External digital triggers can be several different types When triggering your NI signal generator in Standard Function Arbitrary Waveform Arbitrary Sequence Script or Frequency List mode you can select the type of trigger the trigger source and the trigger mode that you want to use LabVIEW Example 1 Call the niFgen Configure Trigger Mode VI to select the trigger mode in which your trigger will generate This mode affects the behavior of the trigger and is dependant on the output mode of the signal generator 2 Call the niFgen Configure Trigger poly VI Choose the instance of the VI that corresponds to the type of trigger you wish to use C Example 1 Call the niFgen configureTriggerMode function to select the trigger mode in which your trigger will generate This mode affects the behavior of the trigger and is dependant on the output mode of the signal generator 2 Call one of the following niFgen Configure Trigger functions niFgen_ConfigureDigitalEdgeStartTrigger niFgen_ConfigureSoftwareEdgeStartTrigger niFgen_ConfigureDigitalEdgeScriptTrigger niFgen_ConfigureDigitalLevelScriptTrigger niFgen_ConfigureSoftwareEdgeScriptTrigger National Instruments Corporation 4 25 NI PXle 5450 User Manual Chapter 4 Programming Creating a Marker Event NI PXle 5450 User Manual You can specify a
112. g state the generation is aborted first General Programming Flow The following diagram shows the general programming flow for applications using NI FGEN Not all NI FGEN VIs appear in the general programming flow as some VIs are considered utility VIs which perform tasks such as resetting the device and returning the revision number of NI FGEN Refer to the NI FGEN LabVIEW Reference or the NI FGEN C Function Reference for more information National Instruments Corporation 4 3 NI PXle 5450 User Manual Chapter 4 Programming Standard Waveform Frequency List Arbitrary Waveform Ld Arbitrary Sequence Arbitrary Script H FGEN an Sr SN FGEN S NI FGEN NI FGEN i i o H amp Required Programming Sequence sistent cs B gt Optional step m gt m Optional branch in required programming sequence gt instrument Driver Overview NI PXle 5450 User Manual To create your application you need an industry standard instrument driver such as NI FGEN to control your device NI FGEN is IVI compliant and works with NI LabVIEW NI LabWindowsTM CVITM and conventional programming languages such as Microsoft Visual C C and Visual Basic 4 4 ni com Chapter 4 Programming NI FGEN includes a set of standard functions for configuring creating starting and stopping waveform generation NI F
113. g table Component Description Waveform Handle Specifies the downloaded waveform to be accessed by the segment A waveform handle is returned for each waveform that is downloaded to the onboard memory Refer to the niFgen Create Waveform or niFgen Allocate Waveform VIs or the niFgen_CreateArbWaveform or niFgen AllocateWaveform functions for more information about downloading waveforms Sample Count Specifies how many samples of a downloaded waveform the segment uses The sample count may not be the actual size of the downloaded waveform If the sample count is less than the actual size of the downloaded waveform only a part of that waveform is used for that segment starting with the first sample of the waveform If the count is more than the actual size of that waveform NI FGEN sends an error If the sample count is set to zero NI FGEN automatically uses the true size of that waveform Waveform loops Specifies the number of times that the waveform or portion indicated by sample count of the waveform loops The maximum number of loops is 16 777 215 Marker offset Specifies where the marker generates within that waveform The offset is referenced to the beginning of the waveform with sample 0 being the first sample of the waveform For more information about markers refer to Markers NI PXle 5450 User Manual Script Mode Script mode allows you to use scripting to link and loop multiple
114. gger lines or the PFI 0 and PFI 1 connectors e The signal generator Start trigger output signal to other devices through any of the PXI trigger lines or the PFI 0 and PFI 1 connectors e The signal generator Sample clock signal to other devices through any of the PXI trigger lines or front panel connectors e The signal generator Sample clock timebase signal to other devices through any of the PXI trigger lines or front panel connectors e The PLL Reference clock source to other devices through any of the PXI trigger lines or front panel connectors In NI FGEN the PXI trigger lines are referred to as RTSI lt 0 6 gt The correlation between PXI_TRIG lt x gt and RTSI lt x gt is one to one For more information about configuring and routing the device internal signals refer to the niFgen Export Signal VI or the niFgen ExportSignal function 2 88 ni com Chapter 2 NI 5450 Overview Synchronization Specifications Your signal generator is based on the National Instruments Synchronization and Memory Core SMC technology and therefore supports TClk synchronization Refer to the NI TClk Synchronization Help for more information about NI TClk Synchronization Calibration For information about the signal generator specifications refer to the device specifications You can access these specifications by navigating to Start All Programs National Instruments NI FGEN Documentation Hardware Specifications or you can visit
115. gnal generator Initiate Generation Started Event Abort Generation Abort Generation Configure Done Event Done Event Trigger Successful Completion Abort Generation Underflow PLL Unlocked and so on Started Marker and Data Marker Events Marker and Data Marker Events The signal generator can be in one of the following six basic states during the course of operation Idle The device is not generating a waveform All session properties or attributes can be programmed in the Idle state In the Idle state the properties or attributes have not necessarily been applied to hardware so the hardware configuration of the device may not match the session property or attribute values The device remains configured as it was the last time a session was committed If the computer has just been powered on reset or the niFgen Reset Device VI or the niFgen ResetDevice function has just been called the device is in the default hardware state NI PXle 5450 User Manual 2 12 ni com Chapter 2 NI 5450 Overview Wait for Trigger After initiating generation the device shifts to the Wait for Trigger state If the trigger source is immediate the device immediately shifts from this state and generates a Started event If the trigger sources are configured for a software trigger or for a hardware trigger from one of the available sources the device remains in this state
116. has just been reset or the niFgen Reset Device VI or the niFgen ResetDevice function has just been called the device is in the default hardware state This means the device is not generating a waveform although depending on the previous state a constant DC voltage from the last waveform sample generated on the output connector may be present National Instruments Corporation 4 1 NI PXle 5450 User Manual Chapter 4 Programming NI PXle 5450 User Manual Committed AIl of the session properties are applied to the device when the session enters the Committed state In the Committed state waveforms and sequences can be loaded into onboard memory If any properties are changed the session implicitly transitions back to idle and the hardware configuration still reflects the previously committed properties Calling the niFgen Commit VI or the niFgen_Commit function from the Idle state verifies all properties configures the device and transitions to the Committed state Generating In the Generating state session properties always reflect the current state of the device and the device is either waiting on a trigger or generating a signal Dynamic properties such as the Arbitrary Waveform Gain property or the NIFGEN_ATTR_ARB_GAIN attribute and the Arbitrary Waveform Offset property or the NIFGEN_ATTR_ARB_OFFSET attribute are applied to the device immediately if set while the session is in the Generating state The following acti
117. he default divide down value is 2 Valid divide down values range from 2 to 4 194 304 If you export the Sample clock timebase to another device to synchronize sampling you can also use the Sample National Instruments Corporation NI PXle 5450 User Manual Chapter 2 NI 5450 Overview clock timebase as the Start trigger for the signal generator Using the Sample clock timebase as the Start trigger begins signal generation at the same place each time relative to the Sample clock timebase This technique is more useful as the divisor becomes larger and while an improvement over using an immediate Start trigger there remains an uncertainty of one Sample clock Routing Signals NI PXle 5450 User Manual PLL Reference clock source A clock signal that is only available when a PLL Reference source has been configured The clock is the source selected as the PLL Reference clock source Out Start trigger A signal generated by the device upon recognizing a start condition that can be routed out various connectors to signal other devices Marker event A digital signal that can be used as a trigger corresponding to a specific sample in the waveform generation This signal controls other devices that require timing information related to a specific point in the generated waveform You can route signals in the following ways e The Marker event generated during an Arbitrary Waveform Generation mode waveform generation to any of the PXI tri
118. he external device you are using as a clock source C Example 1 Call the niFgen ConfigureSampleClockSource function with the sampleClockSource parameter set to an external location Perform the following step if your application is configured for Arbitrary Waveform Arbitrary Sequence or Script output mode 2 Call the niFgen ConfigureSampleRate function with the sampleRate parameter set to the freguency of the external device you are using as a clock source Configuring a Reference Clock You can specify the source for the Reference clock that will be used in a phase locked loop to tune the Sample clock timebase to the frequency stability of the Reference clock LabVIEW Example Call the niFgen Configure Reference Clock VI with Source set to the Reference clock source For example set Source to ClkIn to obtain the Reference clock signal from the Clk In front panel connector Set Reference Clock Frequency to the frequency of the Reference clock NI PXle 5450 User Manual 4 24 ni com Chapter 4 Programming C Example Call the niFgen configureReferenceClock function with the referenceClockSource parameter set to the Reference clock source For example set the referenceClockSource parameter to ClkIn to obtain the Reference clock signal from the Clk In front panel connector Set referenceClockFrequency to the frequency of the Reference clock Configuring Triggers Triggers are signals that cause the NI device to per
119. he generation of the current waveform Aborting the generation exhibits different behaviors for different waveform output modes Sample Size and Resolution The NI 5450 stores arbitrary waveforms in memory as signed 16 bit digital words On the NI 5450 the entire 16 bits are sent to the digital gain circuit the OSP and the DAC Waveform Size and Quantum The NI 5450 onboard memory architecture imposes certain requirements on the waveform size and quantum Waveform Size The minimum waveform size on the NI 5450 depends on the output mode and the trigger mode Refer to the device specifications for the minimum waveform size values for the different modes 3 Note To provide greater programming flexibility NI FGEN does not strictly enforce the minimum waveform sizes stated in the device specifications NI FGEN enforces a minimum waveform size of four samples for all trigger modes two if the OSP block is enabled and the waveform data points have been configured for complex data using the Data Processing Mode property or the NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE attribute so it is possible to generate waveforms that are smaller than the sizes given in the specifications However the device may not be able to fetch data from onboard memory fast enough to keep up with waveform generation at high sample rates This condition may occur if a segment is looping over a very small waveform if a segment is generating a marker within a very
120. ice The timing and behavior of the generation of a waveform sequence is dependent on the trigger mode selected The following figures show the concepts of waveforms and segment sequencing Waveform A Waveform A represents a single cycle of a sine wave that is downloaded to onboard memory Waveform B National Instruments Corporation 2 57 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Waveform B represents a single cycle of a ramp waveform that is downloaded to onboard memory Waveform Segment 1 Loops 3 Waveform Segment shows a segment created using Waveform A repeating or looping three times Waveform Segment 2 Loops 2 Waveform Segment 2 contains Waveform B looping two times Waveform Segment 3 Loops 1 NI PXle 5450 User Manual 2 58 ni com Chapter 2 NI 5450 Overview Waveform Segment 3 contains Waveform A looping only once Segment Segment Segment 1 2 me pd pd gt AT Seguence List Waveform Linking These waveforms are linked in a seguence The concept of using a seguence to generate waveforms is referred to as waveform seguencing or linking and looping waveforms National Instruments Corporation 2 59 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Segment Components You create a sequence segment by segment Each segment is made up of the four components shown in the followin
121. ies of both signals are almost the same The output of the phase detector has a voltage proportional to the phase difference between the two input signals The loop filter receives this signal from the phase detector The loop filter determines the dynamic characteristics of the PLL National Instruments Corporation 5 11 NI PXle 5450 User Manual Chapter 5 Signal Generation Fundamentals Frequency Domain Fundamentals SFDR Spurious free dynamic range SFDR is the usable dynamic range before spurious noise interferes with or distorts the fundamental signal For specification purposes the amplitude of the fundamental signal is usually 1 dBFS SFDR is the measure of the difference in amplitude between the fundamental signal and the largest harmonically or nonharmonically related spur from DC to the full Nyquist bandwidth half the sampling rate A spur is any frequency bin on a spectrum analyzer or from a Fourier transform of the analog signal SFDR is expressed in dBc The following figure illustrates how SFDR is measured Amplitude Spurious Free Dynamic Range Largest Spur fN fg 2 fg Frequency THD NI PXle 5450 User Manual The total harmonic distortion THD of a signal is the ratio of the sum of the powers of the first five harmonics above the measured fundamental frequency to the power of the fundamental frequency THD is usually expressed in dB or dBc Measurements for calculating the THD
122. igure shows the relationship between Start trigger and the waveform output t is the required pulse width on the Start trigger signal ty is the delay from the Start trigger to the waveform output Refer to the NI 5450 specifications for more information about these timing parameters Start Trigger ee es te Wave form Output on CHO 1 ts i Exported Start t Trigger u ta Filtering Effects The NI 5450 also allows you to export signals to trigger other devices based on the waveform output of the signal generator The exported Start trigger Marker event can be exported from the signal generator to signal other devices that waveform generation has started NI FGEN refers to the exported Start trigger as the Out Start trigger The exported Start Trigger event is a slightly delayed version of the Start trigger used for waveform generation It is guaranteed to be at least 150 ns wide The preceding figure also shows the relationship between Start trigger and the exported Start trigger ts is the delay between the Start trigger and the time the device generates the exported Start trigger t 4 is the pulse width of the exported Start trigger signal The delay from the time at which the device receives a trigger to the time at which the analog output signal is generated increases if the digital and or analog filters in the Analog Output path are enabled In the case of digital filtering delay also increases with increase in interpolatio
123. impedance Refer to the device specifications for information about the output impedance tolerance By default NI FGEN assumes that the load impedance is equal to the output impedance If they do not match you can change the load impedance value that NI FGEN uses in its load impedance compensation algorithm NI FGEN takes the load impedance into account when setting the amplitude and provides the amplitude specified in the configured gain setting eliminating the need to use the voltage divider equation NI FGEN compensates to give the desired peak to peak voltage amplitude or arbitrary gain relative to 1 V You can configure the load impedance by calling the Load Impedance property or NIFGEN ATTR LOAD IMPEDANCE attribute The voltage output levels are set in the software and are based upon a 50 Q load termination the default or based on the user specified load resistance For waveform output signal specifications refer to the device specifications The CLK IN front panel connector can accept an external Reference clock external Sample clock or external Sample clock timebase Do not change the external clocks while generating waveforms Only modify the frequency of the external clock before you start the waveform generation or after you stop the waveform generation NI cannot guarantee the quality of the generated signal if you change the external clock during waveform generation External Reference Clock Input The CLK IN
124. in memory By rounding up to the nearest multiple of 128 you can determine that the waveform occupies 20 096 bytes in memory 5 A waveform containing 64 complex samples occupies 256 bytes in memory By rounding up to the nearest multiple of 256 you can determine that the waveform occupies 256 bytes in memory This example is only possible with the OSP block enabled National Instruments Corporation 2 47 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview NI PXle 5450 User Manual Instruction Memory Size Instruction Memory Size Formulae Arbitrary Waveform Size in bytes 256 per waveform Mode Arbitrary Sequence Stepped Size in bytes 208 80 x N Mode FEE EE EE EIE IE ON Continuous Size in bytes 208 64 x N Single Size in bytes 80 64 x N Burst Size in bytes 160 128 x N The instruction size in memory is the size in bytes rounded up to the nearest multiple of 128 bytes t N Number of segments in sequence Examples 1 The memory size required to generate a waveform in Arbitrary Waveform mode is always 256 bytes of onboard memory for that specific waveform Each waveform that is saved to onboard memory uses 256 byes of memory for instructions 2 The memory size required to generate a waveform using Arbitrary Sequence mode and Stepped trigger mode with 50 segments in a sequence list is determined by the following formula Size in Bytes 208 80 x 50
125. inually cycling through the sequence list Only one Start trigger is required to start waveform generation After the device receives a Start trigger the waveform generation starts at the first segment and continues through the last segment and then loops back to the start of the first segment continuing indefinitely All Start triggers after the first Start trigger that starts waveform generation are ignored Start Trigger t j Sequence of Waveforms Repeated Continuously End of All Segments in Sequence List National Instruments Corporation 2 77 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Stepped Trigger Mode The waveform you downloaded generates each time a Start trigger occurs After a waveform finishes generating the last sample of the waveform repeats continuously until the next Start trigger is received When the next Start trigger is received the waveform generates again If a Start trigger is received while a waveform is generating the Start trigger is ignored and another Start trigger is required to regenerate the waveform after the last sample generates The following table provides more information about waveform generation behavior in Arbitrary Waveform and Arbitrary Sequence output modes Output Mode Trigger Behavior Arbitrary Waveform Mode If the Arbitrary Waveform Repeat Count property or the NIFGEN ATTR ARB REPEAT COUNT attribute is set the waveform generates the
126. ion Bytes Rounded Size 100 208 6 608 6 656 64 x 100 Total Onboard Memory Used 78 720 bytes National Instruments Corporation 2 53 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Memory Fragmentation When storing multiple waveforms in NI 5450 memory fragmentation can become a problem Both waveforms and instructions are stored in NI 5450 memory in contiguous blocks These blocks are allocated in multiples of 128 bytes and they are written in the order that you configure them Fragmentation occurs when you delete a waveform or script from memory that was not the last block written Every new NI FGEN session begins with empty memory First multiple waveforms are written to memory nearly filling the device memory as shown in the following diagram Waveform Waveform Waveform Waveform Sequence 1 2 3 4 Instructions If you now try to write Waveform 5 shown in the following figure to the device you find there is not enough memory To make room for the waveform you could delete Waveform 3 to create enough space in memory for Waveform 5 Waveform 5 Waveform Waveform Free Waveform Sequence Free 1 2 Memory 4 Instructions Memory NI PXle 5450 User Manual 2 54 ni com Chapter 2 NI 5450 Overview You now have enough free memory space for Waveform 5 but this space is fragmented so you must also clear and re download all waveforms and generation instructions follo
127. irect DMA window and handles the transfer appropriately 4 31 NI PXle 5450 User Manual Chapter 4 Programming Simulation Mode NI PXle 5450 User Manual C Example 1 Enable the signal generator for direct DMA writes by setting the NIFGEN_ATTR_DIRECT_DMA_ENABLED attribute Once enabled NI FGEN monitors and reports any issues with the direct DMA transfer 2 Identify the waveform data source and set the NIFGEN_ATTR_DIRECT_DMA_WINDOW_ADDRESS attribute to the address provided by your direct DMA compatible data source 3 Set the NIFGEN ATTR DIRECT DMA WINDOW SIZE attribute to the size of the memory window provided by your direct DMA compatible data source 4 UsetheniFgen_WriteBinary1l 6Waveform function to write blocks of data to the signal generator For each block of data written to the signal generator you provide the address of the direct DMA window instead of an array of samples residing in host memory NI FGEN detects when the address is within the direct DMA window and handles the transfer appropriately NI signal generators support simulation Simulating a device enables you to perform the following tasks e Protect your devices by first testing settings and configurations on simulated devices e Verify device behaviors under a wide variety of operating conditions e Start or speed up application development before you have the hardware e Optimize designs and determine ideal design parameters
128. is state until the you use NI FGEN to abort the waveform generation and to return the device to the Idle state Hardware Error An internal hardware error occurred such as data underflow the PLL became unlocked the device shut down due to an over temperature condition and so on The signal generator may still be generating and may be unpredictable at this point When the driver software checks the status of the device an error is returned National Instruments Corporation 2 13 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Analog Output The following figure shows the NI 5450 Analog Output signal path from Waveform Generation Engine Output or Enable Onboard Signal Processing Lowpass Filter Block Output Enable Lowpass Filter Gain DAC Output Enable 0 dB to 3 dB 50 Q Relay NI 5450 analog waveforms are generated as follows 1 The 16 bit digital waveform data from the Waveform Generation Engine or OSP is passed to a digital gain circuit and then high speed DAC This DAC also implements a portion of the Analog Output signal path attenuation with a range of 0 to 3 dB Refer to the NI 5450 specifications for the exact resolution You can adjust the amount of attenuation by configuring the Arbitrary Waveform Gain property or the NIFGEN_ATTR_ARB_GAIN attribute NI FGEN calculates and sets the correct amount of attenuation required corresponding to the gain setting 2 Fo
129. k Timebase M ps Divide M Divide K CHO Channel Sample Clock CLK OUT High PLL W Delay pm PLL p Resolution p p with Phase Divide N CH 1 Oscillator Adjust Sample Channel Sample Clock Clock Deay None Timebase ETE o The NI 5450 has a high resolution internal clock You can change the frequency of this clock by calling the niFgen Set Sample Rate VI or the niFgen_ConfigureSampleRate function When you set a desired sample rate NI FGEN will internally determine and apply appropriate divide down factors 3 Note The jitter of the High Resolution clocking mode is frequency dependent At low frequencies the jitter increases Refer to the device specifications for more information about jitter Phase Locked Loop Reference Clock A phase locked loop PLL is a circuit that tunes the Sample clock timebase to phase lock to an external Reference clock The PLL Reference clock source controls the source of the control voltage that tunes the VCXO of the Sample clock timebase for internal clock update sources The frequency stability and accuracy of the Sample clock timebase matches that of the Reference clock when they are phase locked Using the PLL on your device enables you to frequency lock multiple devices in a single chassis or devices in separate chassis yl Note Refer to the device specifications for information ab
130. l clock you can choose one of the following options e Call the niFgen Initiate VI or the niFgen Tnit function which returns a hardware clocking error because the external Sample clock is gone then clear the error and call the niFgen Initiate VI or the niFgen_Init function again NI FGEN then reprograms the hardware to use the external clock again e Force the device to be recommitted by changing a property or attribute to another value and then back to its original value This action causes NI FGEN to re commit the settings to hardware which does not happen otherwise because NI FGEN does not know that the external Sample clock is gone N Caution When configuring an external Sample clock you can set the sample rate to the exact frequency you are using to avoid data errors by calling the niFgen Set Sample Rate VI or the niFgen ConfigureSampleRate function NI PXle 5450 User Manual 2 40 ni com Chapter 2 NI 5450 Overview External Sample Clock Timebase The Sample clock timebase has an external source that derives device clocking by directly driving the DAC and all waveform generation operations on the device Sample Clock Se Timebase M gt Divide M CLK OUT Divide K CHO Channel Sample Clock Delay Divide N CH1 Channel Sample Clock gt Delay CLK IN Sample Clock Timebase External Sample Clock Timebase You can set the Sample clock tim
131. llowing the DAC the signal follows the Direct path The Direct path can provide a maximum of 1 0 V p differential output into 50 Q with a maximum of 3 dB attenuation pk p 3 The signal then passes through the Output Enable relay When the Output Enable relay is disabled ground is connected to the output through a 50 Q resistor Intentionally waveform generation continues while the output enable relay is disabled When the relay is enabled the analog waveform is seen at the CH 0 connector Enable or disable the output of the analog waveform generator by using the NI PXle 5450 User Manual 2 14 ni com Chapter 2 NI 5450 Overview niFgen Output Enable VI or the niFgen ConfigureOutputEnabled function 4 The signal then passes to the differential channel connector You can configure the output impedance of the analog waveform generator by using the niFgen Configure Output Impedance VI or the niFgen_ConfigureOutputImpedance function yl Note The NI 5450 uses mechanical relays to switch between the optional paths and sections in the Analog Output path When you change a setting that results in a relay switch the bouncing of electromechanical relays on the NI 5450 distorts the output signal for about 10 ms Waveform Amplitude Control The NI 5450 can be configured to achieve required amplitude settings Output Paths and Amplifiers The following figure shows the Direct path from Waveform Generation Engine Output or
132. lowing two options for creating your arbitrary sequence Option 1 Allow NI FGEN to configure the size and allocated space of your waveform 1 Call the niFgen Create Waveform poly VI This VI creates a waveform the size of the data you provide 2 Call the niFgen Create Arbitrary Sequence VI or the niFgen Create Advanced Arb Sequence VI 3 Call the niFgen Configure Arbitrary Sequence VI to configure the gain and offset of the sequence of waveforms Option 2 Manually configure the size and allocated space of your waveform 1 Call the niFgen Allocate Waveform VI to specify the size of the waveform to allocate in the onboard memory of the signal generator 2 Call the niFgen Write Waveform poly VI to write waveform data to the onboard memory you allocated in step 3 3 Call the niFgen Create Arbitrary Sequence VI or the niFgen Create Advanced Arb Sequence VI 4 Call the niFgen Configure Arbitrary Sequence VI to configure the gain and offset of the sequence of waveforms C Example The procedure below provides the basic steps required to configure Arbitrary Waveform mode For a more detailed example of the use of Arbitrary Sequence mode in C refer to the BasicArbitrarySequence or the ArbitrarySequence examples for CVI 1 Call the niFgen ConfigureOutputMode function with outputMode to NIFGEN_VAL_OUTPUT_SEQ 2 Optional Call the nirgen_ClearArbMemory function to clear any previously created arbitrary waveforms
133. lp Technical Resources For answers and solutions visit ni com support for software drivers and updates a searchable KnowledgeBase product manuals step by step troubleshooting wizards thousands of example programs tutorials application notes instrument drivers and so on Registered users also receive access to the NI Discussion Forums at ni com forums NI Applications Engineers make sure every question submitted online receives an answer Standard Service Program Membership This program entitles members to direct access to NI Applications Engineers via phone and email for one to one technical support as well as exclusive access to on demand training modules via the Services Resource Center NI offers complementary membership for a full year after purchase after which you may renew to continue your benefits For information about other technical support options in your area visit ni com services or contact your local office at ni com contact Training and Certification Visit ni com training for self paced training eLearning virtual classrooms interactive CDs and Certification program information You also can register for instructor led hands on courses at locations around the world System Integration If you have time constraints limited in house technical resources or other project challenges National Instruments Alliance Partner members can help To learn more call your local NI office or visit ni com
134. marker and its location by setting an offset location value in number of samples from the start of the waveform If the offset is out of range of the number of samples in that segment NI FGEN returns an error There are two rules for marker placement 1 A marker can be specified only at offsets that are multiples of four samples or two complex samples 2 A marker must be placed at least four samples from the end of the waveform In Burst trigger mode a marker must be placed at least eight samples from the end of the waveform For example for a waveform containing 100 samples a marker at an offset of O or 4 is valid but a marker at an offset of 3 is invalid In addition a marker at an offset of 97 or 100 is always invalid while a marker at an offset of 96 is valid for all trigger modes except Burst The marker can be placed at an offset of 92 for all trigger modes Creating a Marker Event in Arbitrary Waveform Mode You can specify a marker and its location by setting an offset location value in number of samples from the start of the waveform If the offset is out of range of the number of samples in that segment NI FGEN returns an error LabVIEW Example 1 Specify the position of the Marker event by setting the Arbitrary Waveform Marker Position property 2 Export the marker event by calling the niFgen Export Signal VI and setting Signal to NIFGEN VAL MARKER EVENT C Example 1 Specify the position of the
135. me DAC uses the output attenuation the full range of the DAC generates the signal creating the signal at the full 10 0 Vr pe The value of each digital bit is still the original 2 44 mV The signal is applied to an attenuator which reduces the voltage level by a factor of 5 to 2 0 Vok pk The attenuator also reduces the value of each bit which results in an effective bit value of 0 488 mV at the analog output connector The attenuator allows the use of the full range of the DAC and reduces the effective value of each bit corresponding to the degree of attenuation 5 10 ni com Chapter 5 Signal Generation Fundamentals Phase Locked Looping A phase lock loop PLL is a circuit that adjusts a main clock to synchronize to a Reference clock The frequency stability of the Sample clock timebase matches that of the Reference clock when the two are phase locked Phase locking also synchronizes clocks of multiple devices that are phase locked to the same Reference clock The following figure shows a block diagram of a basic PLL Frequency Reference Phase Detector Low Pass Filter Voltage Controlled Oscillator Frequency Output The operation of this circuit is typical of all PLLs A PLL is a feedback control system that controls the phase of a voltage controlled oscillator VCO The frequency reference signal is applied to a phase detector The output of the VCO connects to the other input Normally the frequenc
136. memory Query the Max Waveform Size property or the NIFGEN ATTR MAX WAVEFORM SIZE attribute for the current largest size waveform that can be downloaded to the device You can download floating point signed 16 bit binary or complex floating point waveforms to the device onboard memory For information about downloading waveforms to the onboard memory in LabVIEW refer to the niFgen Create Waveform or niFgen Write Waveform VIs for more information For information about downloading waveforms to the onboard memory in C refer to the niFgen_CreateWaveformF64 niFgen_CreateWaveformI16 niFgen_CreateWaveformComplexF64 niFgen WriteWaveform niFgen WriteBinaryl6Waveform or niFgen_WriteWaveformComplexF64 functions for more information Waveform Quantum Quantum is the increment in samples that waveform sizes must adhere to The NI 5450 has a sample quantum of two allowing waveforms of any even numbered size between the maximum and minimum waveform sizes to be downloaded For example if while in Arbitrary Waveform mode you request to load a waveform of seven samples the task will not complete successfully because the waveform is not an integer multiple of the quantum size Waveform sizes that meet the conditions include 2 4 8 10 12 and so on up to maximum allowable waveform size National Instruments Corporation 2 63 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Streaming Streaming is a way to generate wavefor
137. mpactPCI bus Compatible operation is not guaranteed between CompactPCI devices with different sub buses nor between CompactPCI devices with sub buses and PXI The standard implementation for CompactPCI does not include these sub buses NI signal generators work in any standard CompactPCI chassis PXI specific features such as PXI_Trig bus and PXI_CLK10 reference are implemented on the J2 connector of the CompactPCI bus 3 4 ni com Chapter 3 Integration and System Considerations PXI Trigger Lines Eight PXI bus trigger lines are highly flexible and can be used in a variety of ways For example triggers can be used to synchronize the operation of several different PXI peripheral devices In other applications one device can control carefully timed sequences of operations performed on other devices in the system Triggers may be passed from one device to another allowing precisely timed responses to asynchronous external events that are being monitored or controlled The number of triggers that a particular application requires varies with the complexity and number of events involved System Controller Slot 1 Star Trigger Peripheral Slot 2 Peripheral Slot 3 Peripheral Slot 4 e e e Peripheral Slot N 1 Peripheral Slot N The PXI Specification is implemented with the RTSI bus through the PXI trigger lines PXI Specification requires eight lines PXI_Trig lt 0 7 gt on the P2 J2 connector of the PXI
138. ms that are too large to fit in the onboard memory of the signal generator Streaming can be used in Arbitrary Waveform Arbitrary Sequence or Script output modes To stream waveform data allocate and identify all or a portion of the signal generator onboard memory to act as an onboard waveform for streaming Before initiating waveform generation fill that onboard memory with the first part of your waveform As the waveform is generated space in the onboard memory becomes free and fill that space with new waveform data Repeat the process of filling the freed onboard memory in blocks of new waveform data until the waveform is complete Streaming Waveform Data The following instructions are a guide for configuring your application for streaming For a programmatic example refer to Fgen Arb Waveform Streaming vi for LabVIEW or ArbitraryWaveformStreaming prj for LabWindows CVI As an example we have a 1 6 GB waveform we want to generate and an NI arbitrary waveform generator with 256 MB of onboard memory This 1 6 GB waveform may be in the host memory on disk or data that your application generates dynamically during generation EES neo LANA 256 MB Onboard Memory of NI 5421 Ed rd NI PXle 5450 User Manual 1 Specify the amount of onboard memory to be used for streaming Call the niFgen Allocate Waveform VI or the niFgen_AllocateWaveform function to specify the amount of onboard memory to reserve for str
139. n Enabling the onboard signal processing block can also introduce delay S Note The digital filter for the signal generator is inside the FPGA before the Analog Output path NI PXle 5450 User Manual 2 80 ni com Data Mask Chapter 2 NI 5450 Overview Events The signal generator supports analog data masks and static values The data mask allows you to shield bits of the data to be replaced with the corresponding static value bits For example a mask of OxFFO0 and a static value of OxAAAA applied to a DC waveform with a value of Ox1111 produces a DC waveform with a value of Oxl1AA NI FGEN supports separate and independent analog and digital data masks and static values The analog data mask and analog static value apply to the digital data applied to the DAC and ultimately to the signal on the analog output terminal You can configure an analog data mask by calling the Analog Data Mask or Analog Static Value properties or the NIFGEN ATTR ANALOG DATA MASK and NIFGEN ATTR ANALOG STATIC VALUE attributes An event is a signal generated by the NI device at a device state Typically events are configured to indicate when a specific hardware condition has been met Event Output Behaviors Events can have one of three output behaviors Refer to the following table to determine which output behaviors are supported by each event e Toggle Each instance of the event toggles between high and low
140. n Function 400 MS s 400 MS s 400 MS s 400 MS s Factor and and or or or or Frequency Frequency automatic automatic automatic automatic List modes List modes NI PXle 5450 User Manual 1 6 ni com NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 DIGITAL Optional Optional Optional DATA amp CONTROL CONNEC TOR DDO or Digital Pattern Triggering and Synchronization Trigger Single Single Single Single Single Single Single Single Modes Continuous Continuous Continuous Continuous Continuous Continuous Continuous Continuous Frequency Stepped Stepped Stepped Stepped Stepped Stepped Stepped Stepped List and Burst Burst Burst Burst Burst Burst Burst Burst Arbitrary Waveform Generation Modes Trigger Immediate Immediate Immediate Immediate Immediate Immediate Immediate Immediate Sources External External External External External External External External Software Software Software Software Software Software Software Software RTSI_ RTSI_ RTSI_ RTSI_ RTSI_ RTSI_ RTSI_ RTSI_ lt 0 7 gt lt 0 7 gt lt 0 7 gt lt 0 7 gt lt 0 7 gt lt 0 7 gt lt 0 7 gt lt 0 7 gt PXI_STAR PXI_STAR PXI STAR PXI_STAR PXI_STAR PXI_STAR PXI_STAR PFI lt 0 1 gt PFI lt 0 1 gt PFI lt 0 1 gt PFI lt 0 1 gt PFI lt 0 1 gt PFI lt 0 1 gt PFI lt 0 1 gt PFI lt
141. nal Sample Clock Timebase Timebase Delay Clocking Options Waveform generation is driven by the Sample clock depending on your application some sources may be better choices than others You can use the following sources for the NI 5450 Sample clock National Instruments Corporation Internal Sample clock the onboard clock is used as the Sample clock source and the Sample clock is derived from the Sample clock timebase External Sample clock the Sample clock has an external source that derives device clocking by directly driving the DAC and all waveform generation operations on the device Reference clock the Sample clock is derived from an external source that is phase locked to the Sample clock timebase The phase locked loop PLL Reference clock source specifies the source of the control voltage that tunes the VCXO of the Sample clock timebase for internal clock update sources The PLL circuit adjusts the Sample clock timebase VCXO to synchronize to a Reference clock The frequency stability of the Sample clock timebase matches that of the PLL Reference clock when the two are phase locked Phase locking also synchronizes multiple device clocks that are phase locked to the same Reference clock 2 35 NI PXle 5450 User Manual Chapter 2 NI PXle 5450 User Manual NI 5450 Overview e External Sample clock timebase the Sample clock timebase has an external source that derives device clocking
142. ns You can access these examples through the Start menu by navigating to tartsAll Programs National Instruments NI FGEN Examples yl Note The NI FGEN examples assume that you are already familiar with the ADE in which you will be programming If you are unfamiliar with the ADE consult an introductory text on the ADE before you begin the studying the NI FGEN examples NI FGEN provides the same functionality in two different formats as virtual instruments VIs in LabVIEW and as functions in C based programming languages Basic Steps The tutorial explains how to complete the following programming steps Initialize the session Configure an application Initiate generation Abort generation Close the session RR oe Boe Retrieve error information After you understand the programming process outlined in this tutorial you can find advanced information about programming specific signal National Instruments Corporation 4 9 NI PXle 5450 User Manual Chapter 4 Programming Initialize NI PXle 5450 User Manual generator features with the NI FGEN instrument driver in the Features section Because you can have multiple signal generators connected to your computer you must tell NI FGEN which signal generator to communicate with by opening a session to the signal generator A session establishes a connection between the signal generator and your application After this connection is established the signal generator can t
143. o stop the waveform generation Abort to a Known Voltage Arbitrary Waveform Arbitrary Sequence and Script output modes can abort generation to a known voltage When waveform generation is aborted the analog output signal remains at the voltage corresponding to the last waveform generated until the device is reconfigured for another generation yl Note Closing the NI FGEN session to the device while generating a waveform stops the waveform generation Stopping waveform generation at an unknown point leaves an unknown DC voltage corresponding to the sample value when generation stopped on the CH 0 analog output connector To ensure the output voltage goes to zero volts when closing your applications always disable the output enable relay first and then abort the generation NI PXle 5450 User Manual LabVIEW Example To abort the generation to known voltage complete the following steps 1 During your application download a small constant amplitude waveform that corresponds to the desired output voltage You will generate this waveform at the end of your application 2 Abort generation of the current waveform by calling the niFgen Abort Generation VI 3 Reconfigure the device to generate the constant amplitude waveform 4 Call the niFgen Initiate Generation VI to transition the device to the Generation state 5 Call the niFgen Abort Generation VI to stop generation of the constant amplitude waveform C Example To abo
144. ons ees 2 30 Arbitrary Waveform Generation esse eee see ee 2 30 Baseband Interpolation sesse se se ee ee Se ee Re ee 2 31 Baseband I Q Interpolation 00 0 see se ee ee ee 2 32 Baseband Interpolation Considerations cesses 2 33 Clock Source and Frequency iese see see se se ee ee ee ee ee aa aas 2 35 elf ede RE EE RE 2 35 Internal Sample Clock sesse ses se se ee Se ee Re ee ee 2 37 Phase Locked Loop Reference Clock ee sesse se 2 37 External Sample Clock Sources iese sees see se ee 2 39 External Sample Clock ConsiderationsS iese sesse sesse ese 2 40 External Sample Clock Timebase 0 0 00 eee see se se se 2 41 Exporting old EE EE sess 2 42 Sample Clock EE EE EE EE OE 2 42 Sample Clock Timebase iese ese se ke ee ee ee 2 43 Reference Clock EER RE OR 2 43 Destination OPHONS ees esse ee ee ee ee Se ee ee 2 43 Onboard Memory csi testes EN EE EI 2 44 Onboard Memory for Multichannel Waveform Generation ee sesse se ee se ke Se ke ee Re ee ee ee 2 46 NI PXle 5450 User Manual viii ni com Contents Waveform and Generation Instruction Memory Size 2 46 Waveform Memory Size 00 eee ee see se ee se ee Se ke ee ee 2 46 Instruction Memory Size esse esse se ee se ke ee ke ek ee 2 48 Total Memory S1z sisie sa gde ee ap eg sanseveugceassebtegenstoesees 2 49 Memory Fragmentation see sesse see se ee ee Ge ee ee ee ee 2 54 Signal de LEER RR EE EE OE EE EE 2 55 Syntax fo
145. ons or settings cause a transition between states e Calling the niFgen Initiate Generation VI or the niFgen_InitiateGeneration function in the Idle state causes a transition to the Generating state e Calling the niFgen Commit VI or the niFgen Commit function in the Idle state causes a transition to the Committed state e Calling a create or write waveform VI or function in the Idle state causes a transition to the Committed state e Calling the niFgen Create Arbitrary Sequence VI or the niFgen_CreateArbSequencee function or the niFgen Create Advanced Arb Sequence VI or the niFgen_CreateAdvancedArbSequence function in the Idle state causes a transition to the Committed state e Changing any property in the Committed state causes a transition to the Idle state e Changing a property that is not dynamic in the Generating state returns an error but does not transition out of the Generating state e Calling the niFgen Abort Generation VI or the niFgen_AbortGeneration function in the Generating state causes a transition to the Committed state e Calling the niFgen Close VI or the niFgen_close function from any state closes the NI FGEN session and transitions to the close state If the session is in the Generating state the generation is aborted first 4 2 ni com Chapter 4 Programming e Calling the niFgen Reset VI or the niFgen reset function from any state causes a transition to the Idle state If the session is in the Generatin
146. op of the table Each cell in the table is an index with the valid source and destination terminal for the device If a route is possible between a source and destination terminal the intersecting cell is colored green or yellow A green cell indicates the route can be made without consuming any important resource of your device A National Instruments Corporation 2 55 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview yellow cell indicates that although the route is possible something important must be consumed to create the route Placing the cursor over a yellow square reveals the resource used in the subsystem used indicator 5 Use the niFgen Export Signal VI or the niFgen ExportSignal function to route the signals For terminal name syntax refer to Syntax for Terminal Names Tip You can use the niFgen Export Signal VI or the niFgen ExportSignal function to route the same signal to multiple destinations Syntax for Terminal Names The syntax for terminal names is a unique identifier that refers to a physical terminal in your system To guarantee the uniqueness of a terminal name across multiple devices terminal names begin with a forward slash followed by the name of the device as configured in MAX such as Dev1 A forward slash and the name of the terminal follow the device identifier such as PF1I1 For example the fully qualified terminal name for PFI1 on Devil is Dev1 PFI1 Waveform Generation Output Mode
147. out the PLL reference frequencies available on your device National Instruments Corporation 2 37 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview The following figure shows the NI 5450 Reference Clock Source path Reference Clock Sample Clock Timebase M pr Divide M Divide K CHO Channel Sample Clock CLK OUT CLK IN e epl High PLL W Delay PLL gt Resolution p with Phase gt Divide N CH1 PXI_CLK10 Oscillator Adjust Re Channel Sample Clock SS loc PES Timebase Delay To begin the PLL the phase comparator compares the selected Reference clock to the 400 MHz clock of the Sample clock timebase Next a control voltage proportional to the phase difference between the two clocks is developed and used to tune the Sample clock timebase into alignment with the Reference clock Finally the Sample clock timebase output is routed back to the phase comparator and the loop is closed yl Note When the Reference Clock Source property or the NIFGEN ATTR REFERENCE CLOCK SOURCE attribute is set to None the internal calibration DAC generates the calibration voltage and the PLL circuit is not used Reference Clock Sources The NI 5450 can phase lock its Sample clock timebase to an external signal that is present on the CLK IN front panel connector PXI devices can also phase lock to a 10
148. ported Destination Options CLK OUT PFI lt 0 1 gt PXI_Trig lt 0 6 gt Sample Clock K K21 K 22 K 22 SCTB M Mal M 22 M 22 Reference Clock Always Always Always Note All divisors have a default value of 1 For synchronization purposes the NI 5450 allows you to export your clocks so that other devices can share the timing of the NI 5450 The following sections describe the possible clock routing configurations Sample Clock The Sample clock can be routed to the CLK OUT front panel SMA connector Additionally the exported clock can be divided down by an integer value no less than 2 before being exported to the PFI lt 0 1 gt connectors the NI PXle 5450 User Manual ni com Chapter 2 NI 5450 Overview CLK OUT connector or the PXI_Trig lt 0 6 gt lines Refer to the Exported Sample Clock Divisor property or the NIFGEN ATTR EXPORTED SAMPLE CLOCK DIVISOR attribute for more information about configuring the Sample clock divisor Sample Clock Timebase The Sample clock timebase can be routed to the CLK OUT front panel SMA connector Additionally the exported clock can be divided down by an integer value before being exported to the PFI lt 0 1 gt connectors the CLK OUT connector or the PXI_Trig lt 0 6 gt lines You can configure the Sample clock divisor by calling the Exported Sample Clock Timebase Divisor property or the NIFGEN_ATTR_EXPORTED_SAMPLE_CLOCK_TIMEBASE_DIVISOR attribute
149. r Terminal Names iese see see see se ee ee Ge Re ee ek 2 56 Waveform Generation sesse ee Ese Wee ge dae ERGE GE o GE savas Se ve Rae ig cubed GE GERS Se E E 2 56 Output Modes ss ei seca ket WAY evi OR Se ENE Poe GR niece Ges eed via eed GEE EER ae 2 56 Arbitrary Waveform Mode iese ese se ke ee Ge ee ee ee ee ke 2 57 Arbitrary Sequence Mode ese es ee ee ee ee ee ee 2 57 Segment Componentt isisisi ii ieas ee ee ee ee ee 2 60 Script vi RR RE EE IE OE OR te 2 60 Aborting Generation iisipin ari sern ER EE EE eiae seiat 2 62 Sample Size and Resolution ee ee ee se ee ee Se ee Se Re ee Re ee ke ee 2 62 Waveform Size and Quantum sesse ee Re RA Re Re Re ee ee ee ee 2 62 Waveform Sizes EE EE OE OK ARE 2 62 Waveform JuantUM eee esse esse ese Re Re Re Re Re Re ee ee 2 63 StreamiN g rn An EE ARE EN 2 64 Streaming Waveform Data esse sesse sesse se ee Se ee Se Ge ee ee ee ee 2 64 Streaming to Multiple Channels eee ee ee ee ee ee ke 2 69 Average Performance RateS iese ses se se ee ee Se ee ee ee ee ke 2 69 DAE URE EA N OE EE 2 69 dio dy EE EE 2 69 Improving Streaming Performance esse ses se se ee ee ee ee ee 2 70 PXI Express Bandwidth Considerations 0 0 0 0 eee see se ee ee ee 2 71 Trisgering ses Boss Sees ibs boa EE Ge N ee EE ee Re GEE ER GER ee be Ee see oe Eg GR ge E 2 72 ARE RS EA OE RR OR RR a a 2 73 Typesot Trigpers id EE RE GT ties RE E ines Se EE Ee GE ge EE Pe eds ee Gee Rue ee Eks 2 73 Se
150. ransmit data to your application Sessions also allow the driver to cache previous settings which greatly improves performance LabVIEW Example Call the niFgen Initialize VI to create a session e Resource Name must be set to the device identifier assigned to the signal generator in Measurement amp Automation Explorer MAX You can find or set the resource name for your signal generator by launching MAX and selecting Devices and Interfaces e Id Query specifies whether or not to verify that NI FGEN supports the device you initialize Circumstances can arise where sending an ID query to the device is undesirable When you set this parameter to FALSE the VI initializes the device without performing an ID query e Reset Device allows you to reset the signal generator during initialization e Instrument Handle Out returns a handle that when passed to subsequent VIs allows you to communicate with the signal generator throughout your session C Example Call the niFgen init function to create a session e The resourceName parameter must be set to the device identifier assigned to the signal generator in MAX You can find or set the resource name for your signal generator by launching MAX and selecting Devices and Interfaces e The idQuery parameter specifies whether or not to verify that NI FGEN supports the device you initialize Circumstances can arise where sending an ID query to the device is undesirable When you set this paramet
151. rement and automation applications to deliver significant performance improvements over older architectures The following figure shows a typical PXI chassis installation PXI Chassis Ejector Handle in Down Position National Instruments Corporation 3 3 NI PXle 5450 User Manual Chapter 3 Integration and System Considerations Chassis Guidelines NI PXI signal generators can be installed in the following chassis and slots e PXI chassis PXI signal generators can be installed in any peripheral slot of a PXI chassis e PXI Express chassis PXI signal generators can be installed in the following PXI Express chassis slots e PXI 1 slots Accepts PXI modules e PXI hybrid slots Accepts either PXI modules that are hybrid slot compatible or PXI Express modules Using PXI Compatible Products with Standard CompactPCI Products NI PXle 5450 User Manual The ability to use PXI compatible products with standard CompactPCI products is an important feature provided by the PXI Specification revision 2 1 If you use a PXI compatible plug in device in a standard CompactPCI chassis you cannot use PXI specific functions but you can still use the basic plug in device functions For example the PXI trigger bus on NI signal generators is available in a PXI chassis but not in a CompactPCI chassis The CompactPCI specification permits vendors to develop sub buses that co exist with the basic PCI interface on the Co
152. rigger0 repeat 3 generate waveformA marker0 16 end repeat repeat 2 generate waveformB generate waveformC generate waveformD end repeat end script 4 Optional You can write multiple scripts that exist simultaneously on your device If you write multiple scripts to your device you must select the one you wish to execute by setting the Script to Generate property or the NIFGEN_ATTR_SCRIPT_TO_GENERATE attribute 5 Call the niFgen Initiate Generation VI or the niFgen_InitiateGeneration function to execute the selected script 3 Note Internally the script stores physical device memory locations to refer to named waveforms Thus you must write all waveforms to the device before writing the script or the device does not know where the waveform is located The niFgen Initiate Generation VI or the niFgen_InitiateGeneration function produces an error if this rule is violated If you delete waveforms and rewrite them rewrite the script to update it with the new locations even if the script text has not changed National Instruments Corporation 2 61 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview In some cases at high Sample clocks your script may result in an underflow error Underflow errors in a script can be created by waveform size marker placement and specific script instructions To avoid underflow errors refer to the minimum waveform size in your device specifications Aborting Generation You can abort t
153. rrection is disabled by default in NI FGEN You can enable or disable flatness correction by calling the Flatness Correction Enabled property or the NIFGEN_ATTR_FLATNESS_CORRECTION_ENABLED attribute During external calibration the frequency response of the Analog path in its different configurations is measured using the niFgen Initialize Flatness Calibration VI or the niFgen InitializeFlatnessCalibration function and the niFgen Cal Adjust Flatness VI or the niFgen_CalAdjustFlatness function During generation these measured values are used to compensate for any attenuation at the requested sample rate The compensation is applied by a flatness correcting FIR filter This FIR filter applies attenuation to higher power frequencies so that they become equal to the attenuated frequencies As a result the maximum output voltage is 1 0 V k pk into a 50 Q load Filtering Effects The delay from the time at which the device receives a trigger to the time at which the analog output signal is generated increases if the digital and or analog filters in the Analog Output path are enabled In the case of digital filtering delay also increases with increase in interpolation Enabling the onboard signal processing block can also introduce delay 3 Note The digital filter for the signal generator is inside the FPGA before the Analog Output path National Instruments Corporation 2 17 NI PXle 5450 User Manual Chapter 2 NI 54
154. rror specific to your application you need to read the error description National Instruments Corporation 4 21 NI PXle 5450 User Manual Chapter 4 Programming LabVIEW Example LabVIEW users can read the error description by creating an error indicator from one of the NI FGEN VIs as shown in the following figure Block Diagram Front Panel C Example void ErrorBox ViUInt32 errMsgSize ViChar errMsg if error lt 0 errMsgSize niFgen_GetError vi VI NULL 0 VI NULL errMsg ViChar malloc sizeof ViChar errMsgSize niFgen_GetError vi amp error errMsgSize errMsg ResetTextBox fgenPanel FGEN PANEL ERROR MESSAGE errMsg free errMsg NI PXle 5450 User Manual 4 22 ni com Chapter 4 Programming else if error VI_SUCCESS ResetTextBox fgenPanel FGEN PANEL ERROR MESSAGE Features This section provides instructions for using some of the features of National Instruments signal generators Configuring an Internal Sample Clock You can use the internal onboard Sample clock to control the clocking rates of your signal generator In Arbitrary Waveform or Arbitrary Sequence mode you can choose a clocking mode that will allow you to configure the rate at which this Sample clock runs yl Note The onboard clock is the default Sample clock source If you have not changed the settings for your Sample clock source you do not need to p
155. rs to act when a signal goes below the defined low level or above the defined high level Triggers configured to act in this way are known as level triggers Not all triggers can be configured to be level triggers Software Trigger A software trigger is generated internally by a programmatic call to the niFgen Send Software Edge Trigger VI or the niFgen_SendSoftwareEdgeTrigger function and can occur at any time based upon the conditions specified in the program Trigger sources are software selectable You can use any of the following external input triggers e PEIO or PFI 1 on the front panel connectors e PXI_TRIG lt 0 7 gt lines on the PXI trigger bus backplane 2 74 ni com Chapter 2 NI 5450 Overview The following figure shows the possible trigger sources for the NI 5450 PXI_Trig lt 0 7 gt PXI PXI Trigger Bus Start Trigger MUX a Start Trigger Outs gg gt Software Trigger Refer to Exporting Signals for more information routing signals All triggers are ignored until you call the niFgen Initiate Generation VI or the niFgen_InitiateGeneration function The default trigger source for NI FGEN is Immediate which causes an automatic Start trigger pulse to be generated internally as soon as hardware can generate signals after generation has been initiated You can configure the trigger source with niFgen Configure Trigger VI or the niFgen_ConfigureTriggerSo
156. rt the generation to known voltage complete the following steps 1 During your application download a small constant amplitude waveform that corresponds to the desired output voltage You will generate this waveform at the end of your application 4 20 ni com Chapter 4 Programming 2 Abort generation of the current waveform by calling the niFgen_AbortGeneration function Reconfigure the device to generate the constant amplitude waveform 4 Call the niFgen InitiateGeneration function to transition the device to the Generation state 5 Call the niFgen AbortGeneration function to stop generation of the constant amplitude waveform Closing the Session The closing step closes the session and deallocates any resources the session used Closing the session is important because it releases any temporary buffers that were created to transfer data between the digitizer and the host memory LabVIEW Example Call the niFgen Close VI to close the session C Example Call the niFgen Close function to close the session NI FGEN Error Codes When the NI FGEN driver encounters an error it returns an error code This code value can be in hexadecimal decimal or text depending on your application To understand the error code you need to read the error description For example the error 1074135039 or OxBFFAO0001 Instrument Specific error encompasses many different error cases To better understand the e
157. s NI PXle 5450 User Manual The NI 5450 supports the following output or generation modes e Arbitrary Waveform e Arbitrary Sequence e Script To select an output mode set the Output Mode parameter of the niFgen Configure Output Mode VI or the niFgen ConfigureOutputMode function The output mode of your signal generator determines the type of waveforms your signal generator produces To select an output mode set the Output Mode parameter of the niFgen Configure Output Mode VI or the niFgen_ConfigureOutputMode function 2 56 ni com Chapter 2 NI 5450 Overview Arbitrary Waveform Mode The NI 5450 supports Arbitrary Waveform output mode Arbitrary Waveform mode generates waveforms from user created provided waveform arrays of numeric data The waveform arrays are downloaded to the arbitrary waveform generator onboard memory Arbitrary Waveform mode also uses memory to store the instructions for generating waveform sequences in the onboard memory Arbitrary Sequence Mode Arbitrary Sequence output mode allows you to load multiple waveforms in the onboard memory of the signal generator A finite number of samples make a waveform To generate these downloaded waveforms in a specific order you must prepare a sequence which contains a number of segments in a specific order Each segment specifies a downloaded waveform a number of loops to repeat the selected waveform and a numeric offset in which a marker is generated by the dev
158. s continuously until another Start trigger occurs A Start trigger causes the waveform generation to switch to the waveform defined by the next segment after the current waveform finishes After the sequence list is exhausted the waveform generation returns to the waveform defined by the first segment and subsequent Start triggers will restart the process Only the first Start trigger which signals a transition to the next segment is recognized all subsequent Start triggers are ignored until the currently generating waveform finishes The transition of one waveform to the next can be made amplitude continuous if waveforms in all segments start and end at the same amplitude Alternatively this also can be accomplished by ensuring that the waveforms from one segment to the next end and start at the same amplitude This amplitude continuous transition is shown in the previous Arbitrary Sequence Mode examples by the transitions of Segments to Segment 2 and Segment 3 to Segment 4 The transition from Segment 2 to Segment 3 shows a discontinuous transition going from a positive value on the last sample of the ramp waveform right to a midrange value of the sine waveform Start Trigger Waveform Repeats A 4 Continuously End of End of Segment 1 Segment 3 End of End of Segment 2 Segment 1 National Instruments Corporation 2 79 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Trigger Timing The following f
159. s Supported on SMC Devices Chapter 2 NI 5450 Overview Front Panel oinpe aa gin AR LR Rea en 2 2 Differential Channel Connectors iese sesse se ee ee Re Se ee ee Re ee ee ee 2 4 Load Impedance CompensatHONn iese sesse se ke ek ee ee ee 2 5 CLK IN Connector sr RE SEGE GR rea ates ER GE Ge Ee ee BEE 2 5 External Reference Clock Input see ses ee ee Se ee Se ee ee 2 5 External Sample Clock Input esse sesse sesse ee ee ee ee ee Re ee ke 2 6 External Sample Clock Timebase Input eee see se ee ee ee 2 6 CLK OUT Connector icici es Ee EE GR ge aon ae 2 7 PEE Connectors icc EK ecient mnie ME EG 2 7 ACCESS and ACTIVE LEDS Hie ER Er STEL ee eek eg hla eh ees 2 8 ACEESSLED ese se ee eth ee ee Re de ee ee sd AGE eeee 2 8 ACTIVE LEDE ee Ge Se Ke dae Ee oe Gee ER De ee 2 8 Power Up and Reset Conditions esse sesse se ee Re Se ee Se a ee ee ee ee 2 9 Thermal ShutdOWRE is EE EES RE Re ee Ee see Ee eg ER ed ee gee Ge oe se oe De 2 10 Theory of Operations ES Ee GE Ee T eb ae Ge eon Ge oped bles nite Rar dees 2 11 Block BIERE EER EE OO RE EO aS 2 11 Hardware State Diagram ee SEERDE Gene sede DE bee KEN Re eed SEGE dee ee Pe de 2 12 ril ae ARE EE EE EE ER ae 2 14 Waveform Amplitude Control iese sesse see ee se ee ee ee ee ee 2 15 Output Paths and Amplifiers ees see sesse se se ke ee ee 2 15 N rik tte EE EE N 2 16 Analog Gain Settings 0 cece ee se ee ee ke Se ke ee 2 16 Digital Gai RE N AE N EE 2 17 Flatness Correction ese see s
160. s based on the SMC technology NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Basic Operation Output Standard Standard Standard Standard Standard Standard Standard Arbitrary Modes Function Function Function Function Function Function Function Waveform Frequency Frequency Arbitrary Arbitrary Arbitrary Arbitrary Arbitrary Arbitrary List List Waveform Waveform Waveform Waveform Waveform Sequence Arbitrary Arbitrary Arbitrary Arbitrary Arbitrary Script Sequence Sequence Sequence Sequence Sequence Script Script Script Script Frequency Frequency List List National Instruments Corporation NI PXle 5450 User Manual NI 5402 NI 5406 NI 5412 NI 5421 NI 5422 NI 5441 NI 5442 NI 5450 Standard Function Output Waveform Sine Sine Sine Sine Sine Sine Sine Square Square Square Square Square Square Square Triangle Triangle Triangle Triangle Triangle Triangle Triangle Ramp Up Ramp Up Ramp Up Ramp Up Ramp Up Ramp Up Ramp Up Ramp Ramp DC Noise Ramp Ramp Ramp Ramp Down DC Down DC User Down DC Down DC Down DC Down DC Noise Noise Defined Noise Noise Noise Noise User User User User User User Defined Defined Defined Defined Defined Defined Minimum 0 Hz 0 Hz lt 1 mHz lt 1 mHz lt 1 mHz 0 Hz 0 Hz Freguency Maximum Sine Sine Sine Sine Sine Sine Sine
161. ser Manual at ni com manuals e For additional troubleshooting and support information refer to the LabVIEW Real Time Support main page at ni com support labview real time 4 6 ni com Chapter 4 Programming Creating an Application with LabWindows CVI This topic assumes that you are using LabWindows CVI to manage your code development and that you are familiar with the ADE To develop an NI FGEN application in LabWindows CVI follow these general steps 1 Open an existing or new project file 2 Load the NI FGEN function tree niFgen fp from VXIPnP lt WinNT 9x gt niFgen 3 Use the function tree to navigate the function hierarchy and to generate function calls with the proper syntax and variable values NI FGEN Example Programs for LabWindows CVI To locate the example programs installed with NI FGEN refer to the NI FGEN Instrument Driver Readme If you are using LabWindows CVI 7 0 or later you can use the NI Example Finder to search or browse examples NI FGEN examples are classified by keyword so you can search for a particular device or measurement function To browse the NI FGEN examples available in LabWindows CVI launch LabWindows CVI select Help Find Examples and navigate to Hardware Input and Output Modular Instruments NI FGEN You can also access the examples using the Start menu by selecting Start All Programs National Instruments NI FGEN Examples Creating an Application with Visual C C
162. sible to create and save to memory the instructions for as many sequences as the available free memory allows Examples 1 An application requires using three waveforms with the following sizes 72 132 and 260 samples The waveforms are generated by using Arbitrary Sequence mode and Single trigger mode to configure 20 000 segments in a sequence list The following tables show all the numbers used to determine the total memory stored in the onboard memory 1 281 408 bytes Waveforms Samples Bytes Rounded Size A 72 144 256 B 132 264 384 C 260 520 640 Memory Size 1 280 National Instruments Corporation 2 49 NI PXle 5450 User Manual Chapter 2 NI PXle 5450 User Manual NI 5450 Overview Total Onboard Memory Used 1 281 408 bytes Number of Segments in Memory Sequence Calculation Bytes Rounded Size 20 000 80 1 280 080 1 280 128 64 x 20 000 2 An application requires using six waveforms with the following sizes 480 260 960 492 516 and 604 samples The waveforms are generated by using Arbitrary Sequence mode and Burst trigger mode to configure 10 000 segments in a sequence list The following table shows all the numbers used to determine the total memory stored in the onboard memory 135 296 bytes Total Onboard Memory Used 135 296 bytes Waveforms Samples Bytes Rounded Size A 480 960 1 024 B 260
163. signals being recreated as well as the frequency of the sample rate Looking only at positive frequencies the two frequencies are related by the following equation fai fo nf sl where Joi the aliased images J the desired waveform frequency J the sample rate n an integer either positive or negative As the equation indicates there are an infinite number of these aliased images that occur As n gets larger however the power content of these extra frequencies falls off 5 4 ni com Chapter 5 Signal Generation Fundamentals The following figure shows a 1 MHz sine wave generated by a 6 MS s DAC The dotted line represents an aliased image signal that shows up as a 5 MHz component In this case f is 1 MHz n is 1 and f is 6 MHz resulting in the following formula fai 5 MHz 11 MHz 1 6 MHz I The other possible frequencies of sine waves can be calculated and superimposed onto the sampling points of the image The following figure shows the frequency domain representation of the previous example The vertical arrow at f represents the frequency and signal power of the desired generated signal The other vertical arrows represent the frequencies and signal powers of the aliased image frequency components that appear in the frequency spectrum Signal A 0 Power Images wate Ol 4 MHz 5 MHz 7 MHz 11 MHz 13 MHz 6 MHz 12 MHz fs 2fs In systems where you w
164. sine Response f 20log sof 0 5 0 5cos E where Sis 0 5 x 1 fis Frequency fraction of the I Q Rate Use the Raised Cosine Filter Alpha property or the NIFGEN_ATTR_OSP_FIR_FILTER_RAISED_COSINE_ALPHA attribute to set the a value The following diagram shows an ideal raised cosine filter response with an a of 0 5 The frequency axis is scaled as a fraction of the I Q Rate Amplitude dB ch O 0 0 2 0 4 0 6 0 8 1 1 2 1 4 1 6 1 8 2 Frequency National Instruments Corporation 2 25 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview FIR Filter Type Root Raised Cosine Alpha Values 0 1 to 0 4 This lowpass filter is commonly used in communications applications The passband of the root raised cosine filter stops at 0 5 x 1 o of the VO Rate The stopband of the root raised cosine filter begins at 0 5 x 1 of the VO Rate The transition band of the root raised cosine filter in dB follows the following formula Ideal Root Raised Cosine Response f 2010910 0 5 0 5cos where Sis0 5x 1 a fis Frequency fraction of the I Q Rate Use the Raised Cosine Filter Alpha property or the NIFGEN_ATTR_OSP_FIR_FILTER_RAISED_COSINE_ALPHA attribute to set the a value The following diagram shows an ideal root raised cosine filter response with an o of 0 5 The frequency axis is scaled as a fraction of the I Q Rate Amplitude dB 0 2 0 4 0 6 0 8
165. st segment Slots 2 to 6 of the PXI chassis Utilize Direct DMA 2 70 ni com Chapter 2 NI 5450 Overview PXI Express Bandwidth Considerations National Instruments PXI Express signal generators use PCI Express as the interface to the computer The physical connection between a PXI Express signal generator and a computer is called a PCI Express link When a signal generator generates a waveform it can saturate this link Saturation occurs when the signal generator is copying data to its onboard memory from computer memory as rapidly as possible utilizing all of the bandwidth of the PCI Express link The theoretical bandwidth of the onboard memory of the signal generator is 3 2 GB s and the theoretical bandwidth of the PCIe link is approximately 850 MB s This difference in bandwidths means that transferring data to the onboard memory can saturate the PCI Express link The waveform data download rate is dependent on the system configuration with a maximum of approximately 600 MB s High speed transfers that saturate the PCI Express link can affect other devices when multiple devices share a single PCI Express link For example if an NI PXI Express signal generator is installed in slot 9 of an NI PXIe 1065 chassis controlled by an NI PXIe 8130 controller the signal generator will share bandwidth with any devices installed in Slots 10 through 14 This bandwidth sharing becomes a problem if other devices in the application require guarant
166. te all waveforms that are referenced in the script by calling the one of the niFgen Write Named Waveform functions niFgen_WriteNamedWaveformF64 niFgen_WriteNamedWaveformI16 niFgen_WriteNamedWaveformComplexF64 niFgen WriteNamedwWaveformComplex116 and associate the proper names to them 3 After your waveforms are written to your device call the niFgen_WriteScript function to write the script s containing the generation instructions to be executed The script you write can manage waveform generation based on multiple waveforms and triggers For example you could download waveforms A B C and D into device memory You could then write a script that would wait for a trigger to initiate generation and upon receiving this trigger generate waveform A three times with a marker at position 16 each time and finally generate waveforms B C and D twice BCDBCD The following is the script of this example script myFirstScript wait until scriptTrigger0 repeat 3 generate waveformA marker0 16 end repeat repeat 2 generate waveformB generate waveformC generate waveformD end repeat end script 4 18 ni com Initiate Generation Abort Generation Chapter 4 Programming 4 Optional You can write multiple scripts that exist simultaneously on your device If you write multiple scripts to your device you must select the one you wish to execute by setting the NIFGEN_ATTR_SCRIPT_TO_GENERATE attribute The
167. ted associated associated associated functions functions functions functions functions functions functions functions reduced Calibration utility functions include niFgen GetSelfCal ExtCal niFgen Get niFgen Get ExtCal astTemp niFgen_Getl LSupported niFgen_GetSelfCalLastDateAndTime astDateAndTime niFgen GetSelfCalLastTemp ExtCalRecommendedinterval niFgen_ChangeExtCalPassword niFgen_SetCalUserDefinedInfo niFgen GetCalUserDefinedInfo niFgen_GetCalUserDefinedInfoMaxSize niFgen_ReadCurrentTemperature The minimum frequency available on these devices depends on the memory size of the device as well as the value of the NIFGEN ATTR FUNC MAX BUFFER SIZE attribute You can get the value of this characteristic by calling a query function or by reading an attribute NI recommends that your programs query or read the characteristic rather than depend on a certain value t Varies with the device model or the amount of memory on the device Memory use is a function of the number and size of waveforms and in Arbitrary Sequence mode the number and length of sequences Typically waveforms use most of the memory but if you have a very large number of sequences the available waveform memory is External calibration functions and steps vary from device to device For more information about calibrating your device refer to the calibration procedure for your device it Refer to the device spe
168. tenuation is set to 0 dB CLK OUT output impedance is set to high impedance CLK IN is disabled and has a high impedance to ground PFI 0 and PFI 1 are tristated and have a 10 kQ impedance to ground PXI trigger lines are tristated and floating The sample rate is set to the maximum rate with the Sample clock source set to the internal Sample clock timebase The Sample clock timebase is tuned by the internal reference control voltage 2 9 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Thermal Shutdown NI FGEN supports thermal shutdown capability for the NI 5450 This capability allows the signal generator to detect when it has reached a dangerously high temperature and to then power down to prevent damage to the device Air circulation paths fan settings and space allowances are several factors that can influence device temperature To prevent thermal shutdown follow the guidelines described in the Maintain Forced Air Cooling Note to Users document that shipped with your device Refer to the device specifications to find the correct operating temperature range In the event that the signal generator powers down you are notified with an error message in one of the following ways e NI FGEN returns an error when you use any of the VIs or functions that program the hardware or check hardware status for example the niFgen Commit VI or the niFgen commit function and the niFgen Self Cal VI or the niFgen SelfCal function
169. ter the info code feedback 2008 National Instruments Corporation All rights reserved Important Information Warranty The NI 5450 is warranted against defects in materials and workmanship for a period of 1 year from the date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace equipment that proves to be defective during the warranty period This warranty includes parts and labor The media on which you receive National Instruments software are warranted not to fail to execute programming instructions due to defects in materials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this document is accurate The document has been carefully reviewed for technic
170. terpolation A total interpolation rate of 89 88x falls in the 24 8192 Total Interpolation range in the Interpolation table As this range is measured in steps of 8 you must round down to the nearest multiple of 8 yielding a total interpolation rate of 88x This value corresponds to a sample rate of 391 6 MS s and a worst case image at or below 100 dB National Instruments Corporation 2 33 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Theoretical Theoretical Worst Case Worst Case Image Image Feed Feed VO Interpo through throught Bandwidth lated dB dB H2 Sample 20 MS s Maximum Desired Sample 1 Sample Total Rate Bandwidth VO Rate S s symbol Interpolation MS s Signal Bandwidth 12 to 24k 4 8 to 9 6 k 16384t032768 370 to 400 N A lt 100 in steps of 32 24 to 48 k 9 6 to 19 2 k 8192 to 16384 370 to 400 N A lt 100 in steps of 16 48k to 16 66 M 19 2 k to 24 to 8192 310 to 400 N A 100 6 664 M in steps of 8 16 66 to 33 33 M 6 664 to 12 to 24 300 to 400 N A 88 13 332 M in steps of 4 33 33 to 50 M 13 332 to 20 M 8 267 to 400 N A 61 50 to 67 5 M 20 to 27 M 4 200 to 270 31 23 67 5 to 100 M 27 to 40 M 4 270 to 400 62 45 100 to 135 M 40 to 54 M 2 200 to 270 31 31 135 to 200 M 54 to 80 M 2 270 to 400 62 28 200 to 270 M 80 to 108 M 1 200 to 270 31 8 270 to 399 M 108 to 159 6 M 1 270 to 399 62 8 400 M 120M 1 400 82 52
171. th data generated on one channel of a multichannel signal generator you do not need to perform this step LabVIEW Example Call the niFgen Configure Channels VI with Channels set to the channel or channels you want to configure Valid values are non negative integers For example 0 is the only valid value on devices with one channel while devices with two channels support values of 0 and 1 You can specify more than one channel by inserting commas between values for example 0 1 National Instruments Corporation 4 11 NI PXle 5450 User Manual Chapter 4 Programming NI PXle 5450 User Manual C Example Call the niFgen ConfigureChannels function with channels set to the channel or channels you want to configure Valid values are non negative integers For example 0 is the only valid value on devices with one channel while devices with two channels support values of 0 and 1 You can specify more than one channel by inserting commas between values for example 0 1 Configure Output Mode The Configure Output Mode step determines the type of waveforms that will be generated by your device Options include standard waveforms arbitrary waveforms arbitrary sequences frequency lists and scripts Refer to the Features Supported topic for your device for more information about the type of output modes it supports Configure Standard Function Mode Standard Function output mode allows you to generate standard function
172. that you can use for all external Sample clocks National Instruments Corporation 2 39 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview External Sample Clock Considerations The NI 5450 incorporates high speed digital clocking technology and requires a stable free running Sample clock to operate properly When the signal generator is committed either explicitly by calling the niFgen Commit VI or the niFgen_Commit function or implicitly by writing waveforms or sequences or initiating a generation the external Sample clock must be available to the device If the external clock becomes unstable due to glitching changing frequency or is removed entirely NI FGEN returns a hardware clocking error If necessary you can change the rate or the source of the external Sample clock between subsequent generations by first calling the niFgen Abort Generation VI or the niFgen_AbortGeneration function changing the rate or source and then calling the niFgen Commit VI or the niFgen_Commit function NI FGEN reprograms the NI 5450 for the new settings and you can call the niFgen Initiate Generation VI or the niFgen_InitiateGeneration function to start the next generation If you must remove the external Sample clock between generations after calling the niFgen Abort Generation VI or niFgen AbortGeneration function but before calling the niFgen Initiate VI or the niFgen Tnit function but are not changing the frequency or source of the externa
173. truments Corporation xiii NI PXle 5450 User Manual monospace monospace bold monospace italic Platform Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations variables filenames and extensions Bold text in this font denotes the messages and responses that the computer automatically prints to the screen This font also emphasizes lines of code that are different from the other examples Italic text in this font denotes text that is a placeholder for a word or value that you must supply Text in this font denotes a specific platform and indicates that the text following it applies only to that platform Related Documentation NI PXle 5450 User Manual The following documents contain information that you may find helpful as you read this manual e NI Signal Generators Getting Started Guide provides instructions for installing and configuring NI signal generators e NI Signal Generators Help includes detailed information about the NI 5450 and the NI FGEN VIs and functions e NI 5450 Specifications provides the published specification values for the NI 5450 xiv ni com Features Supported on SMC Devices The following table shows the features supported by NI signal generator
174. truments and have no agency partnership or joint venture relationship with National Instruments Patents For patents covering National Instruments products technology refer to the appropriate location Help Patents in your software the patents txt file on your media or the National Instruments Patent Notice at ni com patents WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS 1 NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN 2 IN ANY APPLICATION INCLUDING THE ABOVE RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY COMPUTER HARDWARE MALFUNCTIONS COMPUTER OPERATING SYSTEM SOFTWARE FITNESS FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION INSTALLATION ERRORS SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES TRANSIENT FAILURES OF ELECTRONIC SYSTEMS HARDWARE AND OR SOFTWARE UNANTICIPATED USES OR MISUSES OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED SYSTEM FAILURES ANY APPLICATION WHERE A SYSTEM F
175. ty or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute 4 Set the external clock source sample rate to the frequency of the Sample Rate property or the NIFGEN_ATTR_ARB_SAMPLE_RATE attribute that you just read 5 Validate that the external Sample clock source is connected to the NI 5450 connector specified in the Sample Clock Source property or the NIFGEN_ATTR_SAMPLE_CLOCK_SOURCE attribute and is generating a clock before you continue configuring the NI 5450 For more information about using external clocks refer to External Sample Clock Sources Frequency Shift The Frequency Shift property or the NIFGEN ATTR OSP FREOUENCY SHIFT attribute can be used to shift the frequency of a baseband signal This property can only be used when the OSP mode has been configured for baseband by setting the OSP Mode property or the NIFGEN_ATTR_OSP_MODE attribute When you are using the NI 5450 with an external I Q modulator the Frequency Shift property or the NIFGEN_ATTR_OSP_FREQUENCY_SHIFT attribute modifies the baseband I Q data such that the resulting RF signal is shifted in frequency Note When the NI 5450 is configured for single channel operation in Real data processing mode you can use the active baseband channel as a direct frequency shifted output in addition to creating RF frequency shifts with an I Q modulator National Instruments Corporation 2 29 NI PXle 5450 User Manual Chapter 2 N
176. uence list The following table shows all the numbers used to determine the total memory stored in the onboard memory 78 720 bytes Waveforms Samples Bytes Rounded Size A 1 000 2 000 2 048 B 2 000 4 000 4 096 C 2 000 4 000 4 096 D 10 000 20 000 20 096 E 20 000 40 000 40 064 F 500 1 000 1 024 G 260 520 640 Memory Size 72 064 Number of Segments in Memory Sequence Calculation Bytes Rounded Size 100 208 6 608 6 656 64 x 100 Total Onboard Memory Used 78 720 bytes 2 52 ni com Chapter 2 NI 5450 Overview 5 An application requires using seven complex waveforms with the following sizes 500 1 000 1 000 5 000 10 000 250 and 130 samples with the OSP block enabled and the Data Processing Mode property set to Complex or the NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE attribute set to NIFGEN_VAL_OSP_COMPLEX Additionally the signal generator is configured for Arbitrary Sequence mode and Continuous trigger mode with 100 segments in a sequence list The following table shows all the numbers used to determine the total memory stored in the onboard memory 78 720 bytes Waveforms Samples Bytes Rounded Size A 500 2 000 2 048 B 1 000 4 000 4 096 C 1 000 4 000 4 096 D 5 000 20 000 20 096 E 10 000 40 000 40 064 F 250 1 000 1 024 G 130 520 640 Memory Size 72 064 Number of Segments in Memory Sequence Calculat
177. ulation Simulate 1 and specify the device you want to simulate with the option string parameter The following example enables simulation of the NI PCI 5421 with 256 MB of onboard memory niFgen_InitWithOptions Resource VI_ON VI_ON Simulate 1 DriverSetup Model 5421 BoardType PCI MemorySize 2684354 56 amp vi For more information refer to the niFgen_InitWithOptions function National Instruments Corporation 4 33 NI PXle 5450 User Manual Signal Generation Fundamentals Bandwidth and Passband Flatness The bandwidth of a signal source is defined as the frequency at which the amplitude of the frequency response is 3 dB lower than the amplitude of the frequency response at DC or a low frequency The bandwidth of a source is limited by the output amplifier design or by filters in the analog output circuit Bandwidth is one of the factors that determines the capability of the source to create signals with specific frequency content Passband flatness is a measure of the amplitude accuracy of the frequency response with respect to frequency Passband flatness is usually specified in dB and it is usually referenced to the amplitude of the frequency response at a designated frequency For example a specification might be listed as 1 dB with respect to the amplitude of the frequency response at 50 kHz This method is used because two different metrology instruments a digital multimeter DMM and a power meter
178. unction The niFgen Configure Channels VI or the niFgen ConfigureChannels function cannot be called after the session has been committed If a channel is inactive it will maintain its output voltage and state until it is made active again or until the device is reset The NI 5450 has two memory banks one for each channel When the niFgen Configure Channels VI or the niFgen ConfigureChannels function is called to configure only one channel as active both channel memory banks will be configured This allows you to use the entire onboard memory for one channel of generation Configuring Channels for OSP The NI 5450 supports one channel of real or complex baseband OSP generation When the OSP is enabled only one channel may be configured as active Individual OSP properties can be configured using the I and Q channel strings T and Q respectively Multichannel Waveform Allocation A waveform consists of all of the data to be generated on all active channels of a device A waveform is allocated on a per device basis and when waveform allocation occurs space is allocated on the device onboard memory for each channel Waveform data must therefore be the same size for each channel Because waveforms contain data for all channels you can only generate one script sequence or arbitrary waveform at a time for all active channels of the device you cannot generate separate scripts sequences or arbitrary waveforms on different
179. urce function Refer to the niFgen Send Software Edge Trigger VI or the niFgen_SendSoftwareEdgeTrigger function for more information about programmatically triggering the device Refer to the device specifications for the minimum Start trigger pulse width required for operation Trigger Modes The NI 5450 has four trigger modes Single Continuous Stepped and Burst These trigger modes are available for Arbitrary Waveform and Arbitrary Sequence output modes National Instruments Corporation 2 75 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Single Trigger Mode When your application is configured for Single trigger mode only one Start trigger is required to begin waveform generation All Start triggers after the first Start trigger are ignored Once the waveform generation is complete the analog output indefinitely settles at the DC value of the last sample in the waveform The following table provides more information about waveform generation behavior in Arbitrary Waveform and Arbitrary Sequence output modes Output Mode Trigger Behavior Arbitrary Waveform Mode Arbitrary Sequence Mode The waveform you downloaded generates only once and waveform generation halts unless the Arbitrary Waveform Repeat Count property or the NIFGEN_ATTR_ARB_REPEAT_COUNT attribute is set in which case the waveform generates the specified number of times Start Trigger v Last Sample
180. utput signal to other devices with fast trigger response times is accomplished using the data marker event from the signal generator as the trigger source for the other device for more precise alignment to the generating waveform You can do this using the RTSI bus PXI trigger lines SYNC OUT PFI 0 and PFI 1 or PFI 4 and PFI 5 without a DDC connector do not support PFI lt 4 5 gt The NI 5450 supports event delays that can manually delay Marker Started and Done events so that they are aligned on a particular Sample clock period National Instruments Corporation 2 85 NI PXle 5450 User Manual Chapter 2 NI 5450 Overview Delay is applied to the event with respect to the analog output of the signal generator For example a delay of 0 Sample clocks aligns the event with the analog output signal while a delay of 2 Sample clocks causes the event to appear two Sample clock periods after the analog output appears All event delays are adjusted in increments of Sample clock periods regardless of the units used to set the delay For example if you provide a value for delay with units of seconds the delay is coerced up to the nearest Sample clock period The event delay attributes must be set before waveform generation is initiated Any changes made to other attributes during waveform generation may change the analog output delay NI FGEN does not compensate for this change in the analog output delay and continues to apply the event dela
181. w the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporation National Instruments respects the intellectual property of others and we ask our users to do the same NI software is protected by copyright and other intellectual property laws Where NI software may be used to reproduce software or other materials belonging to others you may use NI software only to reproduce materials that you may reproduce in accordance with the terms of any applicable license or other legal restriction Trademarks National Instruments NI ni com and LabVIEW are trademarks of National Instruments Corporation Refer to the Terms of Use section on ni com legal for more information about National Instruments trademarks Other product and company names mentioned herein are trademarks or trade names of their respective companies Members of the National Instruments Alliance Partner Program are business entities independent from National Ins
182. waveforms written to it nearly filling the device memory 2 46 ni com Chapter 2 NI 5450 Overview Waveform Waveform Waveform Sequence Sequence Sequence Free e o Instructions Instructions eee Instructions 1 2 n 1 2 vi Memory Calculate the amount of memory that a waveform takes up in the onboard memory with the following two rules 1 Each sample in the waveform uses two bytes of memory space Four bytes are used when the onboard signal processing block is enabled and the Data Processing Mode property is set to Complex or the NIFGEN_ATTR_OSP_DATA_PROCESSING_MODE is set to NIFGEN_VAL_OSP_COMPLEX 2 Memory is written to in blocks of 4 bytes Calculate the memory size by multiplying the number of samples in the waveform by two or four and then rounding this value up to the nearest multiple of 128 Examples 1 A waveform containing 16 samples occupies 32 bytes in memory By rounding up to the nearest multiple of 128 you can determine that the waveform occupies 128 bytes in memory 2 A waveform containing 64 samples occupies 128 bytes in memory By rounding up to the nearest multiple of 128 you can determine that the waveform occupies 128 bytes in memory 3 A waveform containing 68 samples occupies 136 bytes in memory By rounding up to the nearest multiple of 128 you can determine that the waveform occupies 256 bytes in memory 4 A waveform containing 10 000 samples occupies 20 000 bytes
183. wing the deleted waveform The following figure illustrates the result Waveform Waveform Waveform Waveform Sequence 1 2 4 5 Instructions Signal Routing An NI signal generator is capable of sending and receiving signals through the front panel and the PXI or RTSI trigger bus The front panel connectors provides connectivity for the output channel as well as for control lines for sending and receiving clocks triggers and events You can use the PXI and RTSI trigger bus to send and receive events triggers and Sample and Reference clocks All signal routing operations can be characterized by a source and a destination To determine the possible signal routes for your device complete the following steps 1 Launch MAX either by navigating to Start All Programs National Instruments Measurement amp Automation or by double clicking the Measurement amp Automation icon on the desktop 2 Expand Devices and Interfaces Expand NI DAQmx Devices 3 Note If you are using a remote RT target expand Remote Systems find and expand your target and then expand Devices and Interfaces 3 Select your device The view to the right of the MAX configuration tree shows the attributes of your device 4 Click the Device Routes tab below the attributes view A table in the Device Routes view shows the possible sources and destinations for the signal generator Sources are listed in the far left column and the possible destinations span the t
184. y that you was originally configured If an event delay is applied to an event that is being exported to multiple output terminals NI FGEN aligns the event on the first terminal you specified You can configure event delays by calling the Started Event Delay property or the NIFGEN_ATTR_STARTED_EVENT_DELAY attribute or the Done Event Delay property or the NIFGEN_ATTR_DONE_EVENT_DELAY attribute Exporting Signals The signal generator contains seven PXI trigger lines that are available for sending signal generator specific information to other devices that have PXI trigger or RTSI bus connectors The signal generator has connectors on the front panel to route signals to devices external to the PXI Express chassis The following table shows the signals available for export and the lines they can be routed to To determine all possible signal routes for your device refer to Signal Routing 3 Note The PFI outputs have a bandwidth of 200 MHz The PXI Trigger lines have a bandwidth of lt 50 MHz NI PXle 5450 User Manual 2 86 ni com Chapter 2 NI 5450 Overview Destination PFI 0 and PFI 1 PXI_TRIG lt 0 6 gt Connectors CLK OUT Exported Sample Clock Yes when K Yes when K Yes Clocks with K 22 with K 22 Tri and nai ii Sample Clock Yes when M Yes when M Yes Timebase with M 22 with M 22 PLL Reference Yes Yes Yes Source Out Start Yes Yes No trigger Marker Event Yes

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