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Agilent / PXIT N2100A Manual

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1. 1 6 General Information Connector Care Connector Care Today advances in measurement capabilities make connectors and connec tion techniques more important than ever Damage to the connectors on cali bration and verification devices test ports cables and other devices can degrade measurement accuracy and damage instruments Replacing a dam aged connector can cost thousands of dollars not to mention lost time This expense can be avoided by observing the simple precautions presented in this section Electrical Connectors Advances in measurement capabilities make connectors and connection tech niques more important than ever Observing simple precautions can ensure accurate and reliable measurements Handling and storage Keep connectors clean Extend sleeve or connector nut Use plastic endcaps during storage Do not touch mating plane surfaces Do not set connectors contact end down Visual inspection Inspect all connectors carefully before every connection Look for metal particles scratches and dents Do not use damaged connectors Cleaning Clean with compressed air first Clean the connector threads Do not use abrasives Do not get liquid onto the plastic support beads 1 7 CAUTION CAUTION General Information Electrical Connectors Making connections Use connector savers Align connectors carefully Make preliminary connection lightly To tighten turn connector nut on
2. 148 9 Fall Time 141 8 151 1 142 0 150 2 163 5 148 7 151 0 Time 18 03 20 18 03 50 3 32 Using the Control Panel Upgrading the Instrument s Firmware Upgrading the Instrument s Firmware Your new N2100A is compatible with the current version of the control panel software If your PXI chassis includes older N2100A PX2000 333 DCA instruments you may need to upgrade the firmware in those older instru ments as described in this section Connecting to a module with an incompati ble version results in an error message similar to the following PX2000 333 x This program version is incompatible with the module Firmware version Module API version Version info unsupported Program API version 25 To update the firmware and execute the FPGA Loader program perform the following steps Close any open Control Panels On the Windows Start menu click All Programs PXIT PX2000 333 PX2000 333 FW FPGA Loader Using the Control Panel Upgrading the Instrument s Firmware S PX 2000 333 Firmware and FPGA Loader DCA serial number 0506023 API version 26 Firmware build Aug 16 2006 Connect to Modul PxI2 13 INSTR ITSPX2000 333 Fw DeaFw 241 D img elect FPGA File PX2000 333 FW DoaFPGA4 241 D rbf Downloading firmware Cancel Exit 3 Press the appropriate buttons to connect to a given module and note the current module Serial Number API and Firmware Versions 4
3. Power on the PXI chassis and wait for the power up sequence to complete Turn on the PC 2 3 Installation Step 3 Install the N2100A If needed you can use Windows Device Manager to determine if the instru ments have been correctly identified by the BIOS There should be an NI VISA PXI Devices entry with your N2100A PX2000 series instrument as shown in the following figure 2B Device Manager File Action View Help gt 8 4 28 T zl x Computer S Disk drives Display adapters lt 2 DVD CD ROM drives IDE ATAJATAPI controllers gt Keyboards T5 Mice and other pointing devices Monitors E9 Network adapters lt NI PAL Devices lt D MXI 4 Connection Monitor lt NI VISA PXI Devices lt gt Px2000 333 lt Q Px2000 337 PX2000 338 Synthesizer Module Y Ports COM amp LPT SB Processors Sound video and game controllers Storage volumes System devices Universal Serial Bus controllers FE 2 4 Introduction 3 2 To start the Control Panel 3 3 To perform a quick confidence check 3 4 Powering Off the Instrument 3 5 Module Configuration Settings 3 6 Program Settings 3 11 Acquiring Data 3 19 Pattern Acquisition 3 20 Calibrating the N2100A 3 25 Copying and Saving Displayed Test Results 3 28 Upgrading the Instrument s Firmware 3 33 Using the Control Panel Data acquisition O
4. 3 27 Using the Control Panel Copying and Saving Displayed Test Results Copying and Saving Displayed Test Results The DCA Control Panel provides a convenient mechanism to capture dis played measurement results including acquisition data statistics visual traces and test timestamp information for documentation purposes Three Control Panel buttons are used for this purpose Data Copy Graph and Copy Text Data Button Use this feature to view or copy the actual samples in a text format Different data sorting filtering and display options are available The two examples shown below are sampled point data and pattern data in hexadecimal format PX2000 333 Data Samples PX2000 333 Data Samples Sort Point Copy Save to File mt E pP Copy Save to File C XValue A LLL LLH HHL C Tra Se d HLL HLH LHL f Sample Samples _ E Hex Pattern Bini 892 227 7439177 3077458 8715740 4354022 9992304 5630586 1260068 7034650 2545432 8311214 3821996 9460278 5098560 0736841 6375124 2013405 7651687 3289969 9055751 4566533 247 cel P Tare Ane Hex pattern data length 511 ilast byte contains 7 bits Oo FC FD 64 54 56 128 62 AB 192 DB DB 256 7E 7E 320 co E9 384 E3 ES 448 4F 4F Figure 3 8 Examples of Two Data Samples Select Point and the samples will be sorted based on the order in which they were collected X Val sorts the samples based on
5. Mask Display 3 11 Mask Margin 4 10 Mask Margins Rules Agilent 4 13 Mask Margins Rules Tektronix 4 15 Mask Test mode 4 6 Max 5 12 Min 5 11 Module Config 3 4 Multiple Measurements Mode 4 17 N egative Overshoot 5 14 NRZ Non return to zero mode 5 16 NRZ Measurement Mode 4 5 IRZ Thresholds 3 8 IRZ Window Size 3 8 O OMA 5 23 OMA Window Size 3 9 optical and electrical inputs 3 4 Optical modulation amplitude 5 23 Oscilloscope Measurement mode 4 3 Oscilloscope Mode Measurements 5 5 P Pass Fail 5 37 Pattern Acquisition 3 8 3 20 5 41 Pattern Sequence D J Mode Measure ments 5 39 Pattern Sequence D J mode 4 19 PC 2 3 Peak to Peak 5 9 Positive Overshoot 5 13 Presets 3 10 Program Settings 3 11 quick confidence check 3 4 Index 1 Index R remote bridge 2 3 Repetitive 3 19 Resolution 3 14 returning to Agilent 1 15 Rise Time 5 28 RMS 5 10 S Sample Density Color Scheme 3 13 Sample Density Display Information 3 14 Scan for Instruments 3 3 Select Mask 4 6 4 8 service 1 15 Set Defaults 3 10 Set IP Addr 3 10 shipping procedure 1 15 Show Version 3 10 Show Y axis scale 3 13 Signal to Noise Ratio 5 26 Simulator 6 2 Simulator data file format 6 7 Single Edge Jitter 5 33 software digital filters 3 23 Specifications 8 2 8 3 Start Acquisition 3 4 3 19 4 7 static safe accessories 1 6 Statistics 4 17 swabs 1 13
6. This field allows the user to enter the value for an external optical attenuator if any in the input test signal path It can be entered as a ratio or a value in dB with no attenuation as the default All DCA measurements will compen sate for this attenuator and report effective values at its input Same function as the Optical Attenuation field above but for the electrical input path These two values can be set independently Can be set to one of the following Internal The internal reference clock External A user provided clock signal connected to the External Clock input The frequency of this clock must be between 5 and 300 MHz and must match the value of the External Reference Clock Frequency parameter Recovered The clock derived from the received optical or electrical data Internal Auto The internal reference clock After data acquisition the DCA analyzes the acquired samples and attempts to determine the actual data rate This selection thus allows use of the internal clock even if the precise line rate is not known External Auto A user provided clock signal as in External above After data acquisition the DCA analyzes the acquired samples and attempts to determine the actual data rate This selection thus allows use of the internal clock even if the precise line rate is not known The external reference is normally a lower rate than the line rate minimum 5 MHz maximum 300 MHz This allows the reference to b
7. 2 November 1995 as applicable in any tech nical data Safety Notices CAUTION Caution denotes a hazard It calls attention to a procedure which if not correctly performed or adhered to could result in damage to or destruc tion of the product Do not proceed beyond a cau tion sign until the indicated conditions are fully understood and met WARNING Warning denotes a hazard It calls attention to a procedure which if not correctly performed or adhered to could result in injury or loss of life Do not proceed beyond a warning sign until the indi cated conditions are fully understood and met Trademark Acknowledgements Microsoft is a U S registered trademark of Microsoft Corporation Windows and MS Windows are U S registered trademarks of Microsoft Corporation Instrument Markings The CE mark is a registered trademark of CE the European Community ii Contents General Information Introduction 1 2 Electrostatic Discharge Information 1 5 Connector Care 1 7 Returning the N2100A to Agilent 1 15 Installation Introduction 2 2 Using the Control Panel Introduction 3 2 Module Configuration Settings 3 6 Program Settings 3 11 Acquiring Data 3 19 Pattern Acquisition 3 20 Calibrating the N2100A 3 25 Copying and Saving Displayed Test Results 3 28 Upgrading the Instrument s Firmware 3 33 Control Panel Measurement Modes Introduction 4 2 Oscilloscope Measurement Mode 4 3 NRZ Measurements Mo
8. Add Time and the list of measurements is time stamped For multiple measurements this adds a start time end time and elapsed time of the most recent data collection to to the display Refer to Program Settings on page 3 11 for more information 3 19 Using the Control Panel Pattern Acquisition Pattern Acquisition The DCA normally samples its input signal over an interval of one bit time unit interval or UI and reconstructs an eye diagram that is an aggregate of all the signal s states and transitions In pattern sequence acquisition the interval over which the DCA collects samples is the full sequence length in other words as many bit times as the length of the pattern sequence and the reconstructed result is a representation of the entire sequence Although the result is an aggregate of all the sequence periods over which the samples were taken it is coherent with the sequence so any individual transition in the reconstructed sequence consists only of samples from the corresponding tran sition of the input signal The reconstruction of the full pattern sequence makes possible the measure ment of pattern dependent jitter the effect on the shape and timing of a tran sition of the data values that precede it And the availability of the entire sequence as a Series of samples allows the use of digital filtering techniques to realize desired filter characteristics Filter functions can be applied that are specific for
9. Color Scheme Display Using the Control Panel Settings on the Density Display tab Lt Copy The eye display is dark but when copied and pasted a light back ground will be apparent Small Large Selects the pixel size with which sample points are drawn small gives a more precise display large gives a brighter display Overwrite During a repetitive acquisition sequence each measurement is overwritten by the subsequent measurement on the display Add Each measurement is added to form a list of measurements on the GUI Add Time The list of measurements is time stamped For multiple measure ments this adds a start time end time and elapsed time of the most recent data collection to to the display Size Defines the size of the sample window used to create the crossing histogram Defined as a percentage of amplitude Offset Allows the window to be offset from the center by a percentage of the amplitude or Check this control to turn on the Y axis scale To eliminate possible display flicker this check box controls whether points are drawn individually as each one s position is calcuated or whether they are stored in an internal buffer and displayed all at once at the end of each acqui sition calculation cycle Settings on the Density Display tab The Density Display tab allows you to adjust the sample density display options Colors 1 Blue and violet represent the highest sample densities Co
10. Connected to localhost Simulated Module Meas Mode Start Acquisition l Repetitive Module Config 120 Config Data Disconnect E Oscilloscope Meas v eee Module Cal Copy Graph Copy Text Amplitude Peak to Peak RMS Average Measurements _ Pos Overshoot View eye or Neg Overshoot pattern anbe va Offset Scale Auto Cse H Time and Fud Posi amplitude aR Offset Scale controls Cse H Markers Off X Histogram C On YHistogram Markers and histograms Figure 4 1 Oscilloscope Measurement Mode 4 3 X Axis Control Y Axis Control Markers Control Panel Measurement Modes Oscilloscope Measurement Mode The UI selection always displays a single UI Scale is used to zoom in and out Offset UI is used to offset the eye within the display HiRes is used to change the offset by 05 UI or 0 005 UI Zoom is used with the markers enabled the zoom button will set the closest pair of offset and scale settings to zoom within the area selected by the markers The offset and scale values are displayed on the bottom left side of the Eye Diagram Display Auto selects best fit scaling of eye diagram on screen Scale is used to zoom in and out Offset is used offset the eye within the display Click Find to auto find the trace on the screen The Y Axis scale and offset are adjusted accordingly Zoom is used with the markers enabled the zoom button
11. Connectors Keep connectors covered when not in use Use fusion splices on the more permanent critical nodes Choose the best con nector possible Replace connecting cables regularly Frequently measure the return loss of the connector to check for degradation and clean every connec tor every time All connectors should be treated like the high quality lens of a good camera The weak link in instrument and system reliability is often the inappropriate use and care of the connector Because current connectors are so easy to use there tends to be reduced vigilance in connector care and cleaning It takes only one missed cleaning for a piece of grit to permanently damage the glass and ruin the connector Consistent measurements with your lightwave equipment are a good indica tion that you have good connections Since return loss and insertion loss are key factors in determining optical connector performance they can be used to determine connector degradation A smooth polished fiber end should pro duce a good return loss measurement The quality of the polish establishes the difference between the PC physical contact and the Super PC con nectors Most connectors today are physical contact which make glass to glass connections therefore it is critical that the area around the glass core be clean and free of scratches Although the major area of a connector excluding the glass may show scratches and wear if the glass has main
12. PC so the number of display pixels used for the eye diagram is variable Basing the density classification on the display pixels would yield a density display that changes when the application is resized Instead we quantize the data samples to a fixed grid in X and Y and base each sample s density and thus its color on the number of samples that fall into the same grid square The grid remains the same even when the display win dow size changes so the display retains the same appearance Choosing the quantization grid The quantization grid size is selectable giving the user some control over the way samples are grouped Choosing a coarse grid results in the highest fre quency of occurrence values but minimal resolution in X and Y Choosing a fine grid gives the best resolution in X and Y but reduces the likelihood that samples will fall into the same grid square This is best illustrated with a histo gram of sample density bottom left Number I o Min Mbena re The finest grid results in the fewest coincident samples In this distribution half the samples have unique values another fourth occur just twice With the coarsest grid the distribution has a substantially greater fraction of samples that occur multiple times Figure above and to the right Assigning Colors to Sample Densities This implementation uses eight display colors and offers some choice in assigning colors to sample bins One can ass
13. Programs PXIT PX2000 333 PX2000 333 Simulator PX2000 333 DCA Simulator E oix Connected Activity Settings 2nd DCA File E J Reload Files on Startup I Exit on Disconnect The simulator and the control application communicate using TCP IP even when both run on the same computer If you are running a firewall program the firewall will probably object that some application is trying to communi cate over the Internet Either disable the firewall or configure it to allow these programs to communicate as they wish Click Load DCA File and select a data file Some sample data files are installed in the dca data files directory typically Program Files PXIT PX2000 333 dca data files or you can use a file of data written by the DCA Control Panel 6 2 Using the Simulator To run the simulator application s Data Save to File function Open Simulated Sample Data File Look in DCA Data Files amp ef Ee E 2125 Mbps PRBS 7 DCA Data File filtered txt E 2125 Mbps PRBS 7 DCA Data File unfiltered txt E 4250 Mbps PRBS 7 DCA Data File filtered txt E 4250 Mbps PRBS 7 DCA Data File unfiltered txt Filename ERERIE Sas eae eva eM eee eT Files of type Text Files txt Cancel 3 Start the DCA Control Panel application 4 Click I 0 Config and select the simulator option The Port is 1500 by default It s possible to have up to four simulators running on ports 1500 1503 Set Module 1 0 Address
14. Select the new firmware and FPGA files located in the installation directory typically C Program Files PXIT PX2000 333 fw and press start A progress bar appears as the module is updated 5 Once complete shut down the host PC and cycle the power on the PXI chassis 6 After rebooting the PC connect to the module and obtain Module Configuration to confirm proper software upload Introduction 4 2 Oscilloscope Measurement Mode 4 3 NRZ Measurements Mode 4 5 Mask Tests Mode 4 6 Mask Selection Industry Standard and User Defined 4 8 How the Mask and Mask Margin are defined 4 10 Agilent Mask Margins Rules 4 13 Tektronix Mask Margins Rules 4 15 Multiple Measurements Mode 4 17 Pattern Sequence D J Mode 4 19 Control Panel Measurement Modes Control Panel Measurement Modes Introduction Introduction This chapter describes how to control the five measurement modes from the Control Panel For information on all other aspects of using the Control Panel refer to Chapter 3 Using the Control Panel For information on the individ ual measurement algorithms refer to Chapter 5 Measurements 4 2 Control Panel Measurement Modes Oscilloscope Measurement Mode S SSSSS SSzy Oscilloscope Measurement Mode Oscilloscope Measurement mode offers a selection of measurements related to the analog characteristics of the entire signal and the ability to select the dis play time scale Oscilloscope S PXIT PX2000 333
15. Test PASSED 10 margin Control Panel The Eye Mask Test is done automatically after acquisition in this mode Click on Failing Points button for this display API Call FGDCAMaskTestAPI Active X Method GetMaskTestFailPoints 5 37 API Call Active X Method Measurements Eye Mask Test Mode Measurements Find Max Margin Find the maximum mask margin value that results in no more than the speci fied number of sample points that fail the mask test Mask margin for 91 failing points 61 Control Panel After an Acquisition enter the desired number of failing points and click on Find Max Margin botton to perform the test This sequence can be repeated on the same set of test data to determine margin for several fail ing point thresholds Test may be repeated without re acquisition of data FGDCAMaskTestAPI FindThresholdMaskMargin 5 38 Control Panel API Call Active X Method Measurements Pattern Sequence D J Mode Measurements Pattern Sequence D J Mode Measurements The N2100A is capable of performing a pattern capture without the need for a pattern trigger To acquire a pattern To display the following pattern sequence the following steps need to be per formed In the Module Config subpanel set the Pattern Acquisition Option to Enabled No filter Then set either the pattern length or the pattern type Go to Oscilloscope Measure mode and ensure that the Pattern option is s
16. Update Markers Off X Histogram C On Y Histogram Repetitive Module Config Prog Settings 1 0 Contig Data Disconnect M Cou Recta Module Cal Spec Features Reg AZW Copy Graph Copy Text i Reference pattern 101 Length 2 Rise 2 9 ps Fall 2 4 ps Length 3 Rise 4 7 ps Fall 3 1 ps Length 4 Rise 3 1 ps Fall 2 6 ps Control Panel Select the Pattern Sequence DJ option in the main panel API Call FGDCAOscilloscopeAPI Active X Method MeasPatternAcqDetJitterRise MeasPatternAcqDetJitterFall 5 41 Measurements Pattern Sequence D J Mode Measurements 5 42 Introduction 6 2 Configuring the Simulator 6 5 Controlling with User written Applications 6 7 Using the Simulator Using the Simulator Introduction Introduction When the N2100A software is installed a simulator is also installed This reads previously captured data from a file on the system and presents it to the con trol panel as if it were from an instrument The simulator is also a very power ful development tool as it enables the developers to create their own code to control the instrument without having any hardware in place The N2100A Simulator is a program that simulates the N2100A DCA using data files collected from the DCA It is useful for off line development of applications that use the DCA and for demonstration purposes To run the simulator Start the simulator from the Windows Start menu typically Start
17. as Restricted com Santa Rosa CA 95403 USA Warranty The material contained in th vided as is and is subject without notice in future edi is document is pro to being changed ions Further to the puter software as de June 1987 or any eq ined in FAR 52 227 19 ivalent agency regulation or contract clause Use duplication or disclosure of Software is subject standard commercial li to Agilent Technologies cense terms and non DOD Departments and Agencies of the U S Govern ment will receive no greater than Restricted maximum extent permitted by applicable law Agilent disclaims all warranties either express or implied with regard to this manual and any infor mation contained herein including but not limited o the implied warranties of merchantability and fitness for a particular purpose Agilent shall not be liable for errors or for incidental or consequen ial damages in connection with the furnishing use or performance of this document or of any information contained herein Should Agilent and he user have a separate written agreement with warranty terms covering the material in this docu ment that conflict with these terms the warranty erms in the separate agreement shall control Rights as defined in FAR 52 227 19 c 1 2 June 1987 U S Government users will receive no greater than Limited Rights as defined in FAR 52 227 14 June 1987 or DFAR 252 227 7015 b
18. character string used to distinguish two files that might otherwise have the same name It might be used to distinguish between filters of different length or order Filter selections are listed by bandwidth If an optional optstring field is present that string appears in parentheses after the bandwidth specifier Pattern Acquisition Off x Pattem Unfiltered 2488 32 Mb s 2488 32 Mb s Fast 4250 0 Mb s 4250 0 Mb s 400 NAZ Thresholds NAZ Window Size 3 24 Delay Lines Calibration Temperature monitor and delay calibration notification Using the Control Panel Calibrating the N2100A Calibrating the N2100A Clicking Module Cal displays the Calibration dialog box which PETET provides access to _Modue Cal Calibration of the delay lines used in Vector Sampling Dark Current Calibration System Log PX2000 333 Calibration Measure Dark Current System Log OK Figure 3 6 Calibration Dialog Box The Delay Calibration calibrates the delay timers used to position the addi tional samples associated with the Vector Sampling technique A PRBS signal must be applied to the N2100A for the calibration to work correctly During the calibration wait until the message Calibration Complete appears before continuing The Delay Calibration should be run The first time an input path filter is selected When the internal module temperature has changed It is also suggested but not required to perform a cal w
19. performing jitter measurements 3 23 Filter Files Filter File Location Filter File Format Filter List within Display Using the Control Panel Software Filters with Pattern Acquisition With each DCA come filter files constructed to meet the target rates and bandwidths as the DCA s physical input filters These files are stored on the module and are automatically copied to the host for use by the filtering soft ware Available filter selections appear in the Pattern Acquisition control on the Configuration Settings page following the lt Enabled No Filter gt choice In order to use the software filters the Input Path and Filter Selection must be set to the unfiltered path The filter file can only be applied to a signal whose line rate is the same as that of the filter applying a filter file to a different line rate will result in erroneous data Filter files are stored in the DCA Filter Files subdirectory of the PX2000 333 installation directory If the PX2000 333 software is installed to the default location this is C Program Files PXIT PX2000 333 DCA Filter Files File names have the format DCAxxxxxxxBTstring optstring txt where XXXXXXX is the serial number of the DCA to which the filter file applies string is a numeric or mostly numeric character string related to the filter bandwidth for example e 4250 suggests 4250 Mb s e 2488032 suggests 2488 32 Mb s where p represents the decimal point optstring is a
20. probe and the probe adapter has been stabilized after 30 minutes of continuous operation Characteristics provide useful information by giving functional but nonwar ranted performance parameters Characteristics are printed in italics Table 1 Differential Electrical Input Specifications Electrical BW Input 0 1 7000 MHz characteristic Internal Clock Recovery 155 to 3000 MHz Clock Recovery Lock Range 250 ppm Internal Clock stability 0 5 ppm year External Clock Reference 5 300 MHz External Clock Input range CML 200 3000 mV External Clock Lock Range 150 ppm Transition time 20 to 80 35 ps Random Jitter rms 1 ps Maximum Input Range p p 1500 mV Input Noise rms 0 75 mV 8 2 Table 2 Optical Input Specifications Specifications Specifications Unfiltered Optical BW 7 GHz characteristic Optical Responsivity 780 1600 nm Optical NEP 28 dBm Mask Sensitivity 10 dBm at 850 nm 12 dBm at 1310 1550 nm Overload Optical Input 2 dBm Average Optical Power Monitor 15 to 2 dBm Fiber Input 9 50 62 5 um Standard Switchable Filters GigE 2xFC 4xFC Table 3 Environmental Specifications Use indoor Dimensions Three slot PXI module 8 3 Specifications Specifications 8 4 Index A Acquiring Data 3 19 Active X 7 3 ActiveX 7 7 air flow 2 3 Amplitude 5 8 Annotation
21. the product Use original packaging or comparable Original materials are available through any Agilent office Or follow these recommendations e Use a double walled corrugated cardboard carton of 159 kg 850 Ib test strength The carton must allow approximately 7 cm 8 inches on all sides General Information Returning the N2100A to Agilent of the kit for packing material and be strong enough to accommodate the weight of the kit e Surround the kit with approximately 7 cm 3 inches of packing material to protect the kit and prevent it from moving in the carton If packing foam is not available the best alternative is S D 240 Air Cap from Sealed Air Cor poration Commerce California 90001 Air Cap looks like a plastic sheet filled with air bubbles Use the pink antistatic Air Cap to reduce static electricity Wrapping the kit several times in this material will protect the kit and prevent it from moving in the carton 3 Seal the carton with strong nylon adhesive tape 4 Mark the carton FRAGILE HANDLE WITH CARE 5 Retain copies of all shipping papers 1 16 Introduction 2 2 Step 1 Inspect the Shipment 2 2 Step 2 Install the Instrument Driver Software 2 3 Step 3 Install the N2100A 2 3 Installation NOTE WARNING Installation Introduction Introduction The PXI chassis can be controlled using either embedded PXI controller or an external PC using a PCI cPCI PXI remote bridge s
22. the signal line rate and desired filter bandwidth these can also take into account the DCA s inherent frequency response so that the overall response is as close to optimum as possible The pattern sequence acquisition feature adds these capabilities to the DCA It is implemented as a processing step after data acquisition before the pro cessing associated with measurements When this feature is enabled any specified filtering is applied to the reconstructed sequence and measurements made on the result when this feature is disabled the DCA operates in its nor mal single unit interval fashion The benefits are the following Filtering with arbitrary over a wide range filter characteristics including compensation for the DCA s signal path characteristics Identification of signal transitions in context for measurement of pattern de pendent deterministic jitter The limitations are the following The input pattern must be absolutely repetitive to allow its reconstruction from 3 20 Operation Control Panel application Acquisition Using the Control Panel Pattern Acquisition samples taken over many periods The application of this technique is typically limited to unframed signals containing pure data The sequence must be no longer than some upper limit In this implementa tion the sequence can range from a few bits in length up to PRBS 2 1 The signal reconstruction is an averaging process so measurem
23. this screen can be applied to the DCA with the Apply button when highlighted or automati cally with a press of the Start Acquisition button Factory defaults and ten 10 user selectable preset configurations are also available Configuration and presets are persistent and DCA specific PX2000 333 Configuration Settings Global Parameters Line Rate Mb s Custom Line Rate Opt Wavelength Opt Attenuation Elect Attenuation Reterence Clock External Reference 4250 0 850 nm 0 0 dB 0 0 dB Le Le Lel Le Recovered Freq MHz 128 0 Time Base Wander Correction Off DCA Parameters Sample Blocks Input Path and Filter Pattern Acquisition Pattern NRZ Thresholds NRZ Window Size OMA Window Size 16 Refresh Show Version Set Defaults Set IP Addr Presets Save Optical No filter Off E PRBS 2 71 v 20 to 80 Full period v 10 2 Global Parameters Select the required Line Rate from the drop down list or Custom Only enabled if Line Rate is set to Custom Enter the desired line rate Allows the wavelength of the signal under test to be specified This affects the calibration coefficient used to calculate optical power 3 6 Optical Attenuation Electrical Attenuation Reference Clock External Reference Sample Blocks Time Base Wander Correction Using the Control Panel DCA Parameters
24. 0 Cancel Figure 3 9 Annotate Graph and Image Caption Dialog Box 3 30 Using the Control Panel Copying and Saving Displayed Test Results 1400 1200 1000 600 400 200 TEST RUN 5 Fri Aug 11 2006 12 37 37 Module Type PX2000 333 S Module Serial No 0401885 Board Revision 4 FPGA Revision 0 01 01 API Version 26 Driver Version 2 001 Firmware Version 3 005 Build Date Aug 10 2006 TCPAP Address 127 0 0 1 1500 Top 930 1 mY Figure 3 10 Annotated Graph Example The Copy as Excel compatible array is available only on Copy Text option when the Multiple Measurements tab is selected and Repetitive Results Text is set to Add or Add Time option in Prog Settings panel This option reformats the list of results acquired during a repetitive measurements run into a tab sepa rated array of data that can be directly copied into an Excel workbook or other spreadsheet The data are formatted as one column per measured parameter and one row per acquisition The first row of the table has parameter labels In Add Time mode an additional column is populated with the timestamps of the measure ment block at 30 second intervals 3 31 Using the Control Panel Copying and Saving Displayed Test Results Amplitude 46 1 46 1 46 1 46 1 50 7 46 1 46 1 Base 8 9 8 9 8 9 8 9 6 6 8 9 8 9 Top 55 0 55 0 55 0 55 0 57 3 55 0 55 0 Rise Time 134 6 136 7 128 6 110 1 159 7 137 1
25. IP Support NI Visa gt PX2000 333 DCA Figure 7 1 Host Library Overview 7 4 Programming Establishing Communications with the PX2000 333 Establishing Communications with the PX2000 333 The host system communicates with the PX2000 333 module over the PXI Bus or via a TCP IP interface The host controls the PX2000 333 module to set operating modes and parameter values to initiate data acquisition operations and to read module status and measurement result values Before any communications can take place the host system must create a con nection to the PX2000 333 see the Module Connection Functions section of the PX2000 333 DCA Programmer s API and Active X Control document for more details Connections must be closed at the end of the session 7 5 Programming Controlling the DCA from a User Written Test Program Controlling the DCA from a User Written Test Program The PXIT333AXC Active X control is a software component with a standard interface that allows it to be included hosted by a variety of programming and test environments such as LabView LabWindows CVI Visual C Visual Basic Visual C Its properties and methods make DCA functionality available to the controlling program and its optional display presents the same eye dia grams and measurement results as the GUI control application The PX2000 333 DCA Programmer s API and Active X Control docum
26. Input Configuration dialog box that can be used to match the DCA being simulated Seting parameters such as serial number input configuration signal routing and filter frequen cies enable the user to load filter and data files specific to the given DCA 6 5 Using the Simulator Configuring the Simulator Module Input Configuration x Filter 1 0 0 Input Configuration MHz Filter 2 2488 32 Filter 3 1062 5 Filter 4 622 08 Select input configuration and signal routin Electrical only to filter bank Set serial number joao 123 Cancel Measurement results from the simulator may not exactly match those from the DCA module itself The measurement functions in the DCA module have been developed and refined to an extent well beyond those in the simulator The simulator is primarily intended as a qualitative simulation of the DCA 6 6 Simulator data file format Using the Simulator Controlling with User written Applications Controlling with User written Applications Because the simulator presents the same TCP IP network interface as the DCA module it is accessible by any application that can control the DCA Whether an application controls the DCA through the Active X control or the API DLL it can straightforwardly control the simulator as follows Start the simulator and load the desired simulator data file before the applica tion attempts to connect to it Within the application select TC
27. N2100A Option H10 Digital Communications Analyzer User s Guide igi Agilent Technologies Notices Agilent Technologies Inc 2007 No part of this manual may be reproduced in any form or by any means including electronic stor age and retrieval or translation into a foreign lan guage without prior agreement and written consent from Agilent Technologies Inc as gov erned by United States and international copy right lays Manual Part Number N2100 90001 Edition January 2007 Printed in USA Agilent Technologies Inc Digital Signal Analysis Division 1400 Fountaingrove Parkway Technology Licenses The hardware and or software described in this document are furnished under a license and may be used or copied only in accordance with the erms of such license LZW compression decompression Licensed under U S Patent No 4 558 302 and foreign counterparts The purchase or use of LZW graph ics capability in a licensed product does not authorize or permit an end user to use any other product or perform any other method or activity involving use of LZW unless the end user is sepa rately licensed in writing by Unisys Restricted Rights Legend If software is for use in the performance of a U S Government prime contract or subcontract Soft ware is delivered and licensed as Commercial computer software as defined in DFAR 252 227 7014 June 1995 or as a commercial item as defined in FAR 2 101 a or
28. OMA 726 2 uw 843 4 uw 665 1 uw 573 3 uw 170 8 uw 1014 1 uw 745 0 uw Figure 4 13 Multiple Measurements Mode Enabling Statistics on The Multiple Measurements tab includes a check box that enables the statis the Multiple Measurement Tab tics function When Cale Stats is checked minimum maximum average and standard deviation values are collected over the measurements made during 4 17 Control Panel Measurement Modes Multiple Measurements Mode the current repetitive acquisition operation for each of the parameters selected A Meas Stats selector switches the text window between the mea sured values and the statistics When the statistics results are displayed the Copy Text button copies the data displayed Fields are separated by a single tab character The statistics function is available only when the Multiple Measurements tab is selected 4 18 Control Panel Measurement Modes Pattern Sequence D J Mode Pattern Sequence D J Mode A Pattern Sequence D J mode offers measurements of pattern dependent jitter between specified bit ___ Start Acquisition sequences This mode only applies to data acquired X with pattern acquisition For information on pattern acquisition refer to Pattern Acquisition on page 3 20 Transition 1 Fast For additional information on Pattern Sequence D J 101 refer to Pattern Sequence D J Mode Measurements c hoa on page 5 39 The DCA
29. P IP as the communication link type and local host as the module IP address The simulator must run on the same computer as the application that endeav ours to connect to it To run more than one instance of the simulator simulta neously use the TCP IP Port selector on the simulator s Settings panel to select a different port for each simulator instance and then connect each cli ent application to the intended simulator by specifying that port when con necting Four ports are currently available The DCA simulator reads data files written by the control panel application s Data panel To create suitable data files by another means the files must fol low this format The data is in fixed format ASCII with one data point sample per line Col umns are formatted as listed below Intervening positions are filled with space characters 0 0 5000000 9 30 HLL 1 0 0527776 9 56 HLL 2 0 6055553 9 50 LLL 6 7 Using the Simulator Controlling with User written Applications Table 6 1 Simulator Data File Format Column Field 1 The sequence number The simulator does not use this information 8 A colon that follows the sequence number It must be present and properly posi tioned 12 The sample X value a floating point number between 0 and 1 22 The sample Y value a floating point number 32 The transition type one of the following strings LLL Sustained low state following a sustained low state LLH Low to high transi
30. Panel Click Eye Height on the left hand side of the display API Call FGNRZEyeHeightAPI Active X Method MeasNRZEyeHeight 5 20 Measurements Non Return to Zero Mode Measurements Eye Amplitude Eye amplitude is the difference between the logic 1 level and the logic 0 level histogram mean values of an eye diagram measured within the NRZ window amplitude high low Eye Amplitude 520 9 mV Control Panel Click Eye Amplitude on the left hand side of the display API Call FGNRZEyeAmplitudeAPI Active X Method MeasNRZEyeAmplitude 5 21 Measurements Non Return to Zero Mode Measurements Eye Width Eye Width is the horizontal opening of the eye Eye Width T ross2 2Opross2 Teross1 F 2070851 Eye Width 772 ps Ratio 0 966 Control Panel Click Eye Width on the left hand side of the display API Call FGNRZEyeWidthAPI Active X Method MeasNRZEyeWidth 5 22 Measurements Non Return to Zero Mode Measurements OMA Optical Modulation Amplitude Optical modulation amplitude is defined as the difference in power between the high and low levels as measured within the OMA window centered on the crossing OMA P P OMA 558 9 mV Control Panel Click OMA onthe left hand side of the display API Call FGNRZOMAAPI Active X Method MeasNRZOMA 5 23 Control Panel API Call Active X Method Measurements Non Return to Zero Mode Measurements Low Is measured within the NRZ window measure
31. Pressing Start Acquisition will apply any changes automatically as well Displays information about the Module Hardware and Software Loads DCA Factory Defaults These are applied with Apply or Start Acquisi tion buttons Sets Module IP address The first three fields for this address must be the same as that of the pc that is trying to connect to the instrument Clicking Save followed by one of the buttons 1 10 stores the current config uration parameters into one of 10 presets Preset configurations are DCA spe cific and persist until deleted Clicking buttons 1 10 restores a previously saved configuration Clicking Save while holding the Ctrl key followed by 1 10 deletes a preset configuration 3 10 Display Colors Using the Control Panel Program Settings Program Settings Use the Program Settings button on the Control Panel to change the way data is displayed in the Control Panel The dialog box has two tabs General and Density Display with Display Colors and Mask Display settings common to both PX2000 333 Pgm Settings x PX2000 333 Pgm Settings General Density Display General Density Display Display Colors rm Display Colors Display off Mask Display Display off Mask Display s C No colors C Nocolors C No col C Transitions Selection C Transitions Transitions with history Transitions with history C Sample density Sample density Display Traces m Sampl
32. T table mat 1 5 Top 5 6 U Units 3 12 User written Applications 6 7 WwW wrist strap 1 5 X X Axis Control 4 4 Y Y Axis Control 4 4 Y Scale 3 12 Index 2
33. ade between the speci fied Fast pattern and all patterns of the form 10 01 with lengths between 2 and 11 When no transitions are found for a specified length no result is reported for that length The following is typical output from this measure ment Reference Length Length Length Length Length Length Length pattern 101 2 Rise 7 3 ps Fall 4 3 ps 3 Rise 4 5 ps Fall 4 7 ps 4 Rise 1 3 ps Fall 4 2 ps 5 0 2 6 7 8 Rise 0 7 ps Fall Rise 1 9 ps Fall 5 0 p Rise 5 4 ps Fall 9 5 p Rise 7 0 ps Fall 5 6 p 4 20 Introduction 5 2 Oscilloscope Mode Measurements 5 5 Non Return to Zero Mode Measurements 5 16 Eye Mask Test Mode Measurements 5 37 Pattern Sequence D J Mode Measurements 5 39 Measurements Eye Diagram Display Measurements Introduction Introduction This section describes the measurements that the instrument performs The DCA can be controlled automatically through the Application Programming Interface APD or through its Active X Control which also includes an eye display like that of the control application These interfaces allow easy integra tion of the DCA into a test system Examples of this are detailed in Chapter 7 Programming Code can be written in most commonly used languages The N2100A has a number of modes of operation Oscilloscope NRZ Eye Mask Multiple Measurements Pattern Sequence DJ Start the DCA control panel and configure it to make th
34. ailable in Oscilloscope mode Neg Overshoot Avg Power Eye Patter YA A Offset Scale Auto sds C Set X Axis ul C Set Offset Scale Markers Off Histogram C On Histogram Figure 3 5 Pattern Display in Oscilloscope Mode To save a file of data collected with pattern sequence acquisition set the Mea surements selector to Oscilloscope Measurements and the Display selector to Pattern before saving the data Otherwise the simulator will not correctly interpret the data in the file With pattern sequence acquisition enabled measurements are made on the reconstructed sequence but otherwise function normally 3 22 Digital Filter Files amp Capabilities Whatare the Software Filters Using the Control Panel Software Filters with Pattern Acquisition Software Filters with Pattern Acquisition The Pattern Capture feature supports the implementation of software digital filters If selected the given DSP filter is applied to the captured data sequence All limitations that exist for the Pattern Capture also exist for soft ware filters Thus the longest pattern that can be used is a PRBS 2 1 In this mode the random jitter is removed through the averaging process in the pat tern capture Each filter is specified by a file containing an array of numerical data The process of applying the filter convolves the sample data with this array to yield the filtere
35. amp Interface C TCP IP 5 Click Connect The Connected indicator on the simulator GUI will activate as 6 3 Using the Simulator To run the simulator shown below W PX2000 333 DCA Simulator E B Connected Activity Settings if Loaded 4250 Mbps PRBS 7 DCA 2nd DCA File Loaded 4250 Mbps PRBS 7 DCA IV Reload Files on Startup Exit on Disconnect 6 Click Start Acquisition The Activity Indicator will flash on the Simulator panel as the control application reads data from the simulator and displays the data as an eye pattern Use the Module Config controls to change the simulator s settings and use the various measurement and display controls to interact with the simulator 6 4 Using the Simulator Configuring the Simulator Configuring the Simulator By clicking Settings on the Simulator the following panel will appear It can be used to verify constistency with the Module Configuration information on the DCA Control Panel Current Settings TCP IP Port fiso Line Rate 4250 0 Mbs Opt Wavelength fi550nmM Opt Attenuation 1 000 0 00048 Elect Attenuation 1 000 0 00048 Reference Clock Recovered Extemal Reference fize000 Sample Blocks ieee ea aay Input Path and Fiter Optical No fiter Pattern Acquisition is NPZ Thresholds 20 to 80 Full period NRZ Window Size 1000 OMA Window Size J2 0 Input Config Close Clicking Input Config on the panel opens the Module
36. amples illustrat ing the use of the module interfaces are also available 1 2 Optical Features Electrical Features CAUTION NOTE WARNING WARNING WARNING General Information Introduction 4xFC 4 25Gbps using external triggering 3Gbps maximum input rate for NRZ signals using clock recovery function 2 5Gbps including the following e OC 48 STM 16 2 488Gbps STM 16 e G 709 OTUI OC 48 w FEC 2 66606Gbps 2X Fiber Channel 2 125 Gbps 1 0 Gbps including the following e GbE optical 1 25 Gbps e Fiber Channel 1 062 Gbps 622 Mbps optical OC 12 STM 4 155 Mbps optical OC 3 STM 1 155 Mbps minimum input rate for NRZ signals Optical Wavelength Range 780 to 1620 nm Multimode input Connector SMA Female Format NRZ Single ended SE inputs 100 mVp p to 1000 mVp p SE 50 Ohms AC coupled The N2100A is shipped in materials which prevent damage from static The module should only be removed from the packaging in an anti static area ensuring that correct anti static precautions are taken Please note that this former PXIT product PX2000 333 is now part of Agilent Technologies Although most references have been changed to Agilent Technologies this manual may contain some references to PXIT Inc This product is NOT tested for use in medical or clinical applications No operator serviceable parts inside Refer servicing to qualified service personnel Use appr
37. and pulse width variations are then displayed as a widening of the eye diagrams traces which must remain within the template to meet specification Besides being normalized for amplitude the overlaying of signals tends to mask over small or subtle signal characteristics such as overshoot and noise Unless these param eters are grossly out of specification they may not have much visible effect on the eye diagram Histogram fox 1 Histogram Box 3 Terosst Histogram Terss Box 2 Figure 5 1 Eye Diagram 5 3 Measurements Introduction Figure 5 2 Optical Power 5 4 Measurements Oscilloscope Mode Measurements Oscilloscope Mode Measurements The following table summarises the measurements which the DCA can per form in Oscilloscope Mode The DCA software installation includes an HTML document with full details of the Active X and API functions listed in the fol lowing examples Table 5 1 Oscilloscope Mode Measurements Measurement Description Top The average of all sample values identified as high to high transi tions Base The average of all sample values identified as low to low transitions Amplitude The difference between top level and base level of a displayed pulse waveform Peak to Peak The difference between max and min of a displayed pulse waveform RMS The RMS value of the waveform Min The value of the sample point with the lowest amplitude Max The value of the sample point with t
38. ble to damage that is not immediately obvious to the naked eye poor measurements result without the user being aware Microscopic examination and return loss measurements are the best way to ensure good measurements Good cleaning practices can help ensure that optimum connector performance is maintained With glass to glass interfaces any degradation of a ferrule or the end of the fiber any stray particles or finger oil can have a significant effect on connector performance Where many repeat connections are required use of a connector saver or patch cable is recommended Figure 1 3 on page 1 9 shows the basic compo nents of a typical connectors Connecting Body and Ferrule 2 5 mm Mechanical Retainer Fiber 125 um actual fiber s diameter is smaller than a human hair Alignment Key Figure 1 3 Basic components of a connector Figure 1 4 shows the end of a clean fiber optic cable The dark circle in the center of the micrograph is the fiber s 125 um core and cladding which carries the light The surrounding area is the soft nickel silver ferrule Figure 1 5 shows a dirty fiber end from neglect or perhaps improper cleaning Material is smeared and ground into the end of the fiber causing light scattering and poor reflection Not only is the precision polish lost but this action can grind off the glass face and destroy the connector 1 9 General Information Optical Connectors Figure 1 6 shows physical damage to th
39. ccessive data transitions or potential data transitions of the input signal The mean transition time of the data on the upward slope of an eye diagram between two defined thresholds e g 20 to 80 relative to signal Amplitude the full Ul Top and Base levels or rela tive to the NRZ window High and Low levels The mean transition time of the data on the downward slope of an eye diagram between two defined thresholds e g 90 and 10 relative to the full U Top and Base levels or the NRZ win dow High and Low levels 5 16 Measurements Non Return to Zero Mode Measurements Table 5 2 DCA NRZ Measurements 2 of 2 Measurement Description Crossing Percentage Duty Cycle Distortion Edge Jitter Single edge Jitter Deterministic Jitter Crossing Hist ISI Histogram The amplitude of the crossing points relative to the low and high levels The time separation between the rising edge and falling edge at the 50 level of the eye diagram middle threshold Random jitter on the signal Jitter is measured on the rising and falling signal A peak to peak value as well as an rms value is returned The time difference between transitions that immediately follow another transition LHL and HLH and transitions that immediately follow an interval with no transition LLH and HHL Histogram showing the distribution of samples at the crossing point Histogram showing the distribution of the four different trans
40. center to the corresponding outermost vertices This rule applies independently in the horizontal and for the 10 point shape in the vertical axes This is illustrated in Figure 4 12 C Shape Midpoint i sxi ltt N AB 2M Ati By Cy 2 2 vr ya Bc _8 c for all Margin M ABr i 8 0 A C A C aR x1 Figure 4 12 Tektronix Margin Rules for 6 10 Point Masks 4 16 Control Panel Measurement Modes Multiple Measurements Mode Multiple Measurements Mode The Multiple Measurements Mode allows the user to gather and to view all possible measurements on the eye diagram from one capture at the same time After selecting the desired measurements to view the Control Panel dis plays the results concurrently S PX 2000 333 Connected to localhost Simulated Module Start Acquisition Repetitive Multiple Measurements fia Acquiring Amplitude Peak to Peak RMS Average Min 1400 1200 Pos Overshoot Nea Overshoot Ava Power Ext Ratio Eve Height Eve Amplitude Eve Width OMA Low High Signal to Noise Rise Time Fall Time Crossing Pet Duty Cycle Dist Edge Jitter Single Edage Jitter Det Jitter 1000 TTITTITIITIMITTIIiIi ttt iddddad Module Cfg Pgm Settings 120 Config Data Disconnect Module Cal Copy Graph Copy Text None I Cale Stats Amplitude All Meas Bue to peak Markers Ava _ Off X Histogram fhag C On YHistogram
41. charge ESD can damage or destroy electronic components All work on electronic assemblies should be performed at a static safe work station The following figure shows an example of a static safe work station using two types of ESD protection e Conductive table mat and wrist strap combination e Conductive floor mat and heel strap combination Building Ground Building Ground Ohm 7 Resistor A SSS Figure 1 1 Static safe Work Station 1 5 General Information Electrostatic Discharge Information Both types when used together provide a significant level of ESD protection Of the two only the table mat and wrist strap combination provides adequate ESD protection when used alone To ensure user safety the static safe acces sories must provide at least 1 MQ of isolation from ground Refer to Table 2 for information on ordering static safe accessories WARNING These techniques for a static safe work station should not be used when working on circuitry with a voltage potential greater than 500 volts Table 2 Static Safe Accessories Agilent Part Description Number 9300 0797 Static control mat 0 6 m x 1 2 m 2 ft x 4 ft and 4 6 cm 15 ft ground wire The wrist strap and wrist strap cord are not included They must be ordered separately 9300 0980 Wrist strap cord 1 5 m 5 ft 9300 1367 Wrist strap adjustable without cord 9300 1126 ESD heel strap
42. connector make the measurement and then immediately clean it off Never use a gel for longer term connections and never use it to improve a damaged connector The gel can mask the extent of damage and continued use of a damaged fiber can transfer damage to the instrument When inserting a fiber optic cable into a connector gently insert it in as straight a line as possible Tipping and inserting at an angle can scrape material off the inside of the connector or even break the inside sleeve of connectors made with ceramic material When inserting a fiber optic connector into a connector make sure that the fi ber end does not touch the outside of the mating connector or adapter Avoid over tightening connections Unlike common electrical connections tighter is not better The purpose of the connector is to bring two fiber ends together Once they touch tightening only causes a greater force to be applied to the delicate fibers With connec tors that have a convex fiber end the end can be pushed off axis resulting in misalignment and excessive return loss Many measurements are actually improved by backing off the connector pressure Also if a piece of grit does happen to get by the cleaning procedure the tighter connection is more likely to damage the glass Tighten the connectors just until the two fibers touch Measuring insertion loss and return loss Visual inspection of fiber ends WARNING General Information Optical
43. d result A software filter is a digital filter created to match a specific desired frequency response and rise time when convolved digitally with the measured response of the DCA Software filters are only available for optical input The digital fil ter is calculated from the deconvolution of the measured known impulse response of the DCA and the impulse response of the desired filter The output of a continuous filter can be expressed mathematically as the fol lowing y t J ft x h t t at An extension to the discrete digital system is straight forward Agilent provides digital filters to allow the customer the ability to obtain mea surements that closely approximate a fourth order BT filter for the specific hardware frequencies the customer has ordered Agilent digital filters are designed to be utilized when the DCA is configured with the unfiltered optical path and pattern capture mode Once the entire pattern has been captured the digital filter is applied the recorded wave form Digital Filters are module specific and cannot be shared amongst separate modules Incorrectly applying digital filters can lead to unpredictable and erroneous results When using Agilent supplied digital filters ensure the configuration for capturing the data is set correctly Because of the inherent averaging of the data when utilizing pattern capture mode Jitter measurement are not valid It is recommended to utilize the hardware filters when
44. de 4 5 Mask Tests Mode 4 6 Multiple Measurements Mode 4 17 Pattern Sequence D J Mode 4 19 Measurements Introduction 5 2 Oscilloscope Mode Measurements 5 5 Non Return to Zero Mode Measurements 5 16 Eye Mask Test Mode Measurements 5 37 Pattern Sequence D J Mode Measurements 5 39 Using the Simulator Introduction 6 2 Configuring the Simulator 6 5 Contents 1 Contents Controlling with User written Applications 6 7 Programming Introduction 7 2 Software File Structure 7 2 API Structure 7 3 Establishing Communications with the PX2000 333 7 5 Controlling the DCA from a User Written Test Program 7 6 Active X 7 7 Specifications Specifications 8 2 Contents 2 Introduction 1 2 Electrostatic Discharge Information 1 5 Connector Care 1 7 Returning the N2100A to Agilent 1 15 General Information General Information Introduction Introduction The N2100A Digital Communications Analyzer DCA is a PXI based instru ment that automatically performs accurate eye diagram analysis to character ize the quality of sources transmitters from 155 Mb s to greater than 4 25 Gb s for production ATE applications The DCA has five modes of operation oscilloscope NRZ eye mask multiple measurements and pattern capture and software filters Refer to Chapter 5 Measurements for more information The N2100A implements a coherent vector under sampling technique which combines the benefits and measurement capabiliti
45. de Measurements Non Return to Zero Mode Measurements This section describes all the measurements the instrument is capable of per forming in NRZ Non return to zero mode The following table summarizes the measurements types Table 5 2 DCA NRZ Measurements 1 of 2 Measurement Description Extinction Ratio Eye Height Eye Amplitude Eye Width Optical Modulation Ampli tude OMA Low High N ignal to Noise Bit Rate Rise Time Fall Time Extinction ratio is for optical signals only a measure of the ratio of the optical power at the sig nal s 1 level to the power at the signal s 0 level Difference between the 3 sigma value of the high samples within the NRZ window and the 3 sigma value of the low samples within the NRZ window Eye Height is the vertical opening of the eye Difference between the average of the high samples within the NRZ window and the average of the low samples within the NRZ window Time between the latest possible occurrences of one eye crossing to the earliest possible occur rence of the next crossing Difference between the high and low levels measured in a window centered on the eye crossing The OMA Window Size is a specified percentage Mean value of the logical 0 of an eye diagram Mean value of the logical 1 of an eye diagram Ratio of the signal difference between high level and low level relative to the noise present at both levels The rate of su
46. e Density Color Scheme AN LLL LLH HHLJHHH Colors 1 Seld HLL HLH LHL LHH Colors 2 C Intensity Cir All Set All Trans Sing threshold Y Scale Units a Relative Raw mv Display C Fired Caw Signal Sample density distribution Display Repetitive Background Results Text Penan Dak Overwrite Color Intensity Disp C Light C Add olor Intensity Display C Lt copy C Add Time Contrast t Pixel Size Pop up Help Meisn f Small C Off Threshold Display s Large On Contrast H Crossing Histogram Window Threshod H Size Offset fo m 5 244 Show Y axis scale T Update display all at once Figure 3 2 Prm Setting dialog box Display Off Prevents the window from being displayed thus saving the time required to format and present the display information No Colors All samples are displayed using the same color 3 11 Mask Display Display Traces Y Scale Units Display Background Using the Control Panel Settings on the General tab Transitions Samples are displayed using four colors to represent the different transition types LL LH HL and HH Transitions with history Samples are displayed using eight colors to represent transition types LLL LLH LHH LHL HLL HHL HLH and HHH In this case the actual sample is taken on the transition between the latter two bits Sample Density Sample is displayed based on whichever option has been selected within t
47. e defined How the Mask and Mask Margin are defined Masks define an the area in the reconstructed image of the eye where no sam ple points should exist It always consists of an area in the center of the eye and can optionally have areas above and below the eye Top Mask Yi Measured Top Level y 1 X x 1 at this crossing point X x 0 atti crossing point Measured Base Level y 9 Ya Bottom Mask Figure 4 6 Mask Definition All y axis values are defined relative to the measured base level y 0 with the measured top level being y 1 The Y level can be determined based on either the top and bottom of the entire eye or the high and low based on a certain percentage around the middle of the eye All x axis values are defined relative to the left side crossing point x 0 with the right side crossing point being x 1 4 10 Control Panel Measurement Modes How the Mask and Mask Margin are defined The center mask can have 4 6 or 10 sides depending on the checkbox set tings in the setup form below This form is also used to setup the position of all the vertices of the mask Fibre Channel 12 o Mask Margin Margin Compatibility Cancel jo Agilent x pee V Mask uses X1 4 I Mask uses X5 X6 Y5 Y6 IV Mask uses Y3 Y4 Mask Y levels are relative to jo of eye x4 0 785 ma e P i wa a y2 0 800 yo 0500 ya 1 300 ye 0 000 F
48. e entered as a partic ular frequency freq for example freq 10 MHz or as a division of the line rate rate for example rate 128 DCA Parameters Specifies the number of sample points that will be used to create the eye Each sample block consists of 1 024 sample points Small variations in the DCA s internal reference time base appear as low fre quency jitter wander in the acquired signal For mask tests and edge jitter measurements the DCA analyzes the acquired samples and removes the effect of this wander This release adds the option of wander correction for all DCA measurements Wander correction improves the accuracy of DCA measure ments but may increase the time required to acquire data For applications 3 7 Input Path and Filter Pattern Acquisition Pattern NRZ Thresholds NRZ Window Size Using the Control Panel DCA Parameters for which measurement speed is important it may be desirable to disable wan der correction By reducing the number of blocks to less than 20 the effect of wander is significantly reduced Used to set the input path and filter this is selected from a list of options that are available on the specific DCA For Example Optical DCA allows selection of the Unfiltered and Available Filter Paths The Pattern Acquisition control has selections for Off Enabled No filter and any specific filter capabilities that are present Off in this mode the standard DCA eye captu
49. e glass fiber end caused by either repeated connections made without removing loose particles or using improper cleaning tools When severe the damage of one connector end can be transferred to another good connector endface that comes in contact with the damaged one Periodic checks of fiber ends and replacing connecting cables after many connections is a wise practice The cure for these problems is disciplined connector care as described in the following list and in Cleaning Non lensed Connectors on page 1 13 Use the following guidelines to achieve the best possible performance when making measurements on a fiber optic system e Never use metal or sharp objects to clean a connector and never scrape the connector e Avoid matching gel and oils 2 4 Figure 1 4 Clean problem free fiber end and ferrule a Le an Os Ee Figure 1 5 Dirty fiber end and ferrule from poor cleaning 1 10 General Information Optical Connectors sae sus m Figure 1 6 Damage from improper cleaning While these often work well on first insertion they are great dirt magnets The oil or gel grabs and holds grit that is then ground into the end of the fiber Also some early gels were designed for use with the FC non contacting con nectors using small glass spheres When used with contacting connectors these glass balls can scratch and pit the fiber If an index matching gel or oil must be used apply it to a freshly cleaned
50. e mask with the margin applied This will be recalculated each time the Start Acquisition button is clicked or continuously in Repetative Acquisition Mode In the Trace Dis play these points are highlighted in yellow In the Results Display Area the appropriate text is displayed Either Test PASSED or Test FAILED with the number of points that failed subtotaled by individual mask region Test FAILED 7 points of 16384 45 margin Center 7 Upper 0 Lower 0 The Find Max Margin button enables to user to find the maximum mask margin for x amount of failing points In the figure below the user wants to determine the maxmimum mask margin available for the heighest number of failing points but no more than 25 The answer in this example is 51 for 22 points Margin below this level would result in less failing points total and margin above this level would result in more failing points nnel m argin Tektronix Mask margin for 22 failing points 51 Figure 4 4 Find Max Mask Margin The Find Max Margin calculates results without the need to reacquire data This allows the user to converge on a desired answer by trying different values and clickinging the Find Max Margin for each one When no data is present the error message NO DATA will be displayed 4 7 Control Panel Measurement Modes Mask Selection Industry Standard and User Defined Mask Selection Industry Standard and User Defined Clicking the Select Mask wil
51. e measurements you want The N2100A automatically performs accurate eye diagram analysis to charac terize the quality of transmitters from 155 Mb s to beyond 4 25 Gb s This chapter lists all possible measurements for each mode including Definition Optical and Electrical including formula for parameter calcula tion Examples with screen shots OC48 STM4 signals were used Display Configuration How to perform the measurements using the API Eye diagrams are becoming a key figure of merit for most computer and com munications system standards including Gigabit Ethernet Sonet Infiniband Rapid IO PCI Xpress and others Some designers would rightfully argue that insertion and return loss are more important and representative of the inter connect performance at a given speed however the eye diagram provides a clear visual representation as to whether or not the interconnection by itself would meet the eye diagram test specification for a given standard 5 2 Measurements Introduction The Eye Diagram provides a longer term view of the signal taking into account the relative time position of successive pulses It provides less infor mation about pulse shape but allows a more thorough analysis of the cumula tive effects of wander and jitter Eye diagrams require the use of DPO mode or other long term persistence method to preserve information from the preced ing pulses then overlaying them in a continuous fashion The timing
52. edge at the mid level of the eye diagram The 50 threshold is calculated either on the total wave form amplitude full period or the NRZ windowed high low levels mV 1600 1400 1200 1000 800 600 Duty Cycle Distortion 10 0 ps 2 5 Control Panel Click Duty Cycle Distortion on the left hand side of the display API Call FGNRZDutyCyDistortionAPI Active X Method MeasNRZDutyCycleDistortion 5 31 Measurements Non Return to Zero Mode Measurements Edge Jitter Edge Jitter is a measure of the difference in the time domain of the earliest transitioning sample and the latest This is measured at the crossing point Jitter 41 5 ps Peak to Peak 7 8 ps RMS Control Panel Click Edge Jitter on the left hand side of the display API Call FGNRZJitterAPI Active X Method MeasNRZJitterPeakToPeak MeasNRZJitterRMS 5 32 Control Panel API Call Active X Method Measurements Non Return to Zero Mode Measurements Single Edge Jitter Single Edge rising Jitter is a measure of the difference in the time domain of the earliest transitioning rising point and the latest This is measured at the crossing point The single edge falling jitter is also available Jitter 41 5 ps Peak to Peak 7 8 ps RMS Click Single Edge Jitter on the left hand side of the display FGNRZFallJitterAPI FGNRZRiseJitterAPI MeasNRZSingleEdgeJitterPP MeasNRZSingleEdgeJitterRMS 5 33 Control Panel API Call Active X Met
53. elected N A PatternAcqFilterSel PatternAcqLength LoadPatternAcqFilterFile LoadPatternAcqFilterFileByValue MeasPatternAcqDetJitterRise MeasPatternAcqDetJitterFall 5 39 Control Panel API Call Active X Method Measurements Pattern Sequence D J Mode Measurements To apply software filters with pattern acquisition To apply the software filters the following steps need to be performed In the Module Config sub panel set the Pattern Acquisition Option to the desired fil ter Then set either the pattern length or the pattern type N A PatternAcgFilter Sel PatternAcqLength LoadPatternAcqFilterFile LoadPatternAcqFilterFileByValue 5 40 Measurements Pattern Sequence D J Mode Measurements DJ based on Pattern Acquisition The Pattern Acquisition capability provides the DCA with an alternate Deter ministic Jitter measurement The deterministic jitter as derived by two partic ular bit patterns can be extracted using the pattern capture option The user is able to define two patterns to compare The user is also able to define one base pattern which can then be compared against all other patterns The dif ference in ps of the crossing point between the two patterns under test is returned Si PX2000 333 Connected to PXI3 13 INSTR Optical 5 x Pattern Sequence D J Y Transition 1 Fast 101 Length 3 C 7101 Transition 2 Slow C Lenath 2 Eo 71001 All
54. ent is a detailed reference for the capabilities offered by the Active X control In quick over view the steps to add the DCA to one s test application and use it to acquire data are the following Add an instance of the PXIT333AXC control to your project using the procedures appropriate to your programming environment Call one of the module connection functions OpenTcp OpenTcpByVal OpenPxi OpenPxiByVal to establish communications with the DCA module Set the DisplayMode property to select whether the eye display window is visible and if so what information it displays Call the various configuration functions to set module parameters such as line rate reference clock select number of sample data points etc Call one of the data acquisition functions AcquireDCA or AcquireDCAWithMask to acquire data Call the various measurement functions to make measurements on the acquired data and retrieve the results or call one of the data acquisition functions GetDCASampleData or GetDCASampleDataVariant to retrieve the data sample values Update the module parameter settings and or make additional measurements as your application requires At the end call the Close function to release the communication link to the module 7 6 Programming Active X Active X ActiveX allows developers to create code and applications from any of a multi tude of different languages and build a defined interface to that code making it acce
55. ents of random non periodic jitter made on the reconstructed signal do not accurately reflect the jitter present on the input signal The reconstruction process does not preserve individual data samples It is possible that an individual sample that might fail a mask test will not appear in the reconstructed output Implementation of the filter with computational techniques requires significant processing Performance with this capability enabled will be slower than with out For reasons of memory performance and ease of implementation this ca pability is structured as a layer above the DCA s normal processing and implemented on the host computer rather than on the DCA itself It thus plac es a load on the host processor and its performance depends on the host s speed and available resources Configuring the pattern sequence acquisition involves specifying The pattern sequence length The filter if any to be applied The Pattern Acquisition control has selections for Off Enabled No filter and a list of software filters Gif any that are available for the module Pattern Acquisition Enabled No filter Pattern Acquisition Enabled No filter Pattem PRBS 2 7 1 Pattem SetLenath 259 The Pattern control used to specify the length of the repeating pattern sequence has selections for PRBS 27 1 PRBS 2 1 PRBS 24 1 K28 5 K28 7 and Set Length for patterns of arbitrary length When Set Length is selected the
56. er core may not affect performance unless the imperfections keep the fibers from contacting The procedures in this section provide the proper steps for cleaning fiber optic cables and Agilent Technologies universal adapters The initial cleaning using the alcohol as a solvent gently removes any grit and oil If a caked on layer of material is still present this can happen if the beryllium copper sides of the ferrule retainer get scraped and deposited on the end of the fiber during insertion of the cable a second cleaning should be performed It is not uncommon for a cable or connector to require more than one cleaning Agilent Technologies strongly recommends that index matching compounds not be applied to their instruments and accessories Some compounds such as gels may be difficult to remove and can contain damaging particulates If you think the use of such compounds is necessary refer to the compound manufacturer for information on application and cleaning procedures Table 1 1 Cleaning Accessories Item Agilent Technologies Part Number Pure isopropyl alcohol Cotton swabs 8520 0023 Small foam swabs 9300 1223 Compressed dust remover non residue 8500 5262 Do not use any type of foam swab to clean optical fiber ends Foam swabs can leave filmy deposits on fiber ends that can degrade performance Apply pure isopropyl alcohol to a clean lint free cotton swab or lens paper Cotton swabs can be used as long as no cott
57. erence between the maximum positive and the maximum negative amplitudes of a waveform as shown below Peak to peak 734 4 mV Control Panel Click Peak to Peak on the left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscPeakToPeak 5 9 Control Panel API Call Active X Method Measurements Oscilloscope Mode Measurements RMS Root mean square rms refers to the most common mathematical method of defining the effective voltage or current of an AC wave To determine rms value four mathematical operations are carried out on the function representing the AC waveform 1 Take average of all samples 2 Take sum of sample i average 2 3 Divide sum by of samples 4 Take square root of result N VALUE pyng Xsampteri average 1 RMS 465 6 m Click RMS on the left hand side of the display FGDCAOscilloscopeAPI MeasOscRMS 5 10 Measurements Oscilloscope Mode Measurements The value of the sample point with the lowest amplitude Min 0 4 mY Control Panel Click Min on the left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscMinLevel 5 11 Measurements Oscilloscope Mode Measurements Max The value of the sample point with the highest amplitude Max 734 8 mV Control Panel Click Max on the left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscMaxLevel 5 12 Measuremen
58. es of a real time scope with the bandwidth of a sampling scope The main features of the N2100A DCA Optical and electrical inputs with a 780 to 1600 nm optical wavelength range Performance and accuracy guaranteed at 850 1310 1550 nm Calibration is performed at 850 nm Wavelength responsivity measurement data provided by the O E vendor is used to scale the 850 nm calibration for use at 1310 and 1550 nm Calibration accuracy is verified at 850 nm and 1550 nm on all modules Input rate from 155 Mb s to gt 4 25 Gb s Includes up to 3 user selectable filters and one unfiltered path The filter selections to choose from are 1 25 2 125 4 25 Gb s Internal clock recovery for signals up to 3 Gb s The N2100A also operates with a user provided external clock between 5 MHz and 300 MHz or with its own internal clock Bit Rate independent Pattern acquisition without the need for a pattern trigger Software and hardware 4th order BT filters The DCA is a PXI based instrument Either an embedded PC or a stand alone PC connected via a remote bridge such as National Instrument s MXI 4 card can be used to control it via the PXI bus It is also possible to connect to the instrument via a TCP IP connection The module is supplied with a Windows Control Panel application an Active X interface usable from environments such as Visual C Visual Basic and LabWindows a programmer s API and libraries callable from user written applications Software ex
59. ew feature selects pixel color based on the number of samples that occur at that pixel thus displaying information about the signal that doesn t appear in the traditional display This is shown above on the far right A number of options and settings affect the sample density display and can be used to tailor it to one s liking But it is appropriate first to explain its opera tion in more depth In the simplest description one might say that a data point that occurs many times in the sample data should be displayed at a different color from one that occurs just once With more colors one can define multiple thresholds for the number of times a given data point occurs and display each frequency of occurrence group in its own color But the definition of when two samples have the same value essential to how often does a given sample occur is complex The collected data has 12 bit resolution in Y and 23 bit resolution in X so there are approximately 34 bil 3 14 Using the Control Panel Settings on the Density Display tab lion unique sample values If we use the data s inherent resolution to deter mine sample coincidence then it is unlikely there will be even two samples of the same value Alternatively one can say that two samples have the same value when they fall on the same display pixel This appears to be the approach used by the Tektronix DCA But our Control Panel application is resizable and runs on the user s
60. f use 2 2 WARNING WARNING NOTE Installation Step 2 Install the Instrument Driver Software Ensure that the PXI chassis containing the N2100A provides adequate earth grounding Ensure that the air supply to the chassis is working correctly The N2100A requires an optimal air flow within the chassis It is recommended to regularly change filters on PXI Chassis Step 2 Install the Instrument Driver Software If using an external PC and remote bridge turn the PXI chassis power off If using an embedded controller remove all N2100A modules from the chassis This step ensures that the PC BIOS will be able to locate the instruments in the PXI chassis Log onto the PC with administrator privileges so that you can install the software 3 Go to the Agilent website www agilent com find pxit 4 Click on the Technical Support link and then the Drivers link 5 Download the latest version of the following driver Agilent N2100A PX2000 333 DCA Driver Once the download has completed run the file N2100Alnstall exe During the installation you will enter the user name and organization Select the all users option to ensure the software is available to all users of the PC Click Next When install is finished click Finish The N2100A control software is now installed Step 3 Install the N2100A With the PC and chassis powered off install the N2100A module in an available slot in a PXI chassis
61. field to the right is enabled in which the pattern length is entered The length must be between 4 and 2047 With Pattern Acquisition enabled any data acquisition operation acquires data over the sequence length reconstructs the sequence and applies the selected filter The reconstructed eye diagram is displayed and any measurements invoked are made on the reconstructed eye 3 21 Displaying Acquired Data in Text Format Graphical Sequence Display Saving pattern sequence data for use with the simulator Measurements General Using the Control Panel Pattern Acquisition If the Pattern Length setting doesn t match the actual sequence length or if the input signal is not absolutely repetitive the sequence reconstruction will be incoherent and the eye display will appear garbled The acquired data pattern can be displayed and processed through the Data Samples dialog box described in Copying and Saving Displayed Test Results on page 3 28 Multiple display modes sorting fields and file manipultaion functions are available On the Oscilloscope Measurements tab is a selector for Eye or Pattern display Selecting Pattern changes the display to show the entire reconstructed sequence The Time Axis controls may be used to display the sequence with suitable horizontal resolution and to scroll through it The Pattern selection is enabled only when pattern sequence acquisition is active Pattern sequence display is only av
62. guration setting Choices are 10 to 90 20 to 80 and 30 to 70 of either the total Waveform Amplitude Full Period Top and Base or the NRZ Windowed High and Low Levels Rise Time X high threshold Xiow threshold Rise Time 84 9 ps Control Panel Click Rise Time on the left hand side of the display API Call FGNRZRiseTimeAPI Active X Method MeasNRZRiseTime 5 28 Control Panel API Call Active X Method Measurements Non Return to Zero Mode Measurements Fall Time The measurement is made on the falling edge between the thresholds selected by the NRZ Threshold configuration setting Choices are 10 to 90 20 to 80 and 30 to 70 of either the total Waveform Amplitude Full Period or the NRZ Windowed High and Low Levels Fall Time Xiow threshold Xhigh threshold Fall Time 73 0 ps Click Fall Time on the left hand side of the display FGNRZFallTimeAPI MeasNRZFallTime 5 29 Measurements Non Return to Zero Mode Measurements Crossing Percentage Signal level at the point where the rising and falling edges cross expressed as a percentage of the signal amplitude Crossing Percentage 42 7 Control Panel Click Crossing Pct on the left hand side of the display API Call FGNRZCrossingPercentAPI Active X Method MeasNRZCrossingPercent 5 30 Measurements Non Return to Zero Mode Measurements Duty Cycle Distortion The time separation between the rising edge and falling
63. he lowest amplitude Pos Overshoot Overshoot is a distortion that follows a waveform edge transition This distortion occurs after the rising edge crosses through the wave form threshold levels Neg Overshoot Overshoot is a distortion that follows a waveform edge transition This distortion occurs after the falling edge crosses through the wave form threshold levels Avg Power The average power read by the PIN diode Optical signals only 5 5 Measurements Oscilloscope Mode Measurements Top Top is the average of all sample values identified as high to high transitions Top 660 1 mY Control Panel Click Top onthe left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscTopLevel 5 6 Measurements Oscilloscope Mode Measurements Base Base is the average of all sample values identified as low to low transitions Base 121 2 mY Control Panel Click Base on the left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscBaseLevel 5 7 Measurements Oscilloscope Mode Measurements Amplitude The vertical difference between the Top and Base of the signal Top Base Amplitude Amplitude 539 0 mv Control Panel Click Amplitude on the left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscAmplitude 5 8 Measurements Oscilloscope Mode Measurements Peak to Peak Peak to peak pk pk is the diff
64. he sample density tab No Colors Sets the pixel display for the mask test to the standard blue pixel display Sample points failng the mask test are highlighted in this mode Selection Sets the Mask pixel display to that selected in the display colors option Settings on the General tab All All transitions will be displayed Sel d Only transitions selected using the LLL HHH buttons will be displayed Clr All Sets all the LLL HHH buttons to the OFF state Set All Sets all the LLL HHH buttons to the ON state Trans Sets all the LLL HHH buttons that represent a LH or HL transition to ON LLL HHH Allows individual traces to be switched On or OFF The warning Some traces not displayed appears above the Trace Display Area when not all transitions are selected Relative Only displays the used part of the Y Axis Fixed Always includes the zero value on the Y Axis Signal mV electrical or uW optical For a DCA with the optical input selected the option is uW For a DCA with an electrical input selected the option is mV Both of these are calibrated options Raw mV In this mode the non calibrated mV value of the instrument is returned The user should not need to use this option Dark The eye display has a dark background Light The eye display has a light background 3 12 Pixel Size Repetitive Results Text Crossing Histogram Window Show Y axis scale Update display all at once Sample Density
65. hen the Line rate chang es The DCA firmware monitors the internal module temperature and notifies the user or the client application when the temperature has changed so much that delay recalibration is required 3 25 Dark Current Calibration System Log Using the Control Panel Calibrating the N2100A In the Control Panel application a pop up window appears when data acquisi tion is performed notifying the user that recalibration is advisable Calibration may be performed by clicking Calibrate Now or at a later time using the Cali bration dialog box described above Delay Line Calibration Warning x Please perform delay calibration and then repeat the data A acquisition The temperature of the internal delay lines has changed since the currently selected filter s last delay calibration or no calibration has been performed for the currently selected fiter since the power was turned on I Do not show this message again Calibrate Now Figure 3 7 Calibration WarningDialog Box Data acquisition functions in the Active X control and the module API return a status value FG_DELAYCAL_REQD indicating that recalibration is advisable Calibration for optical signals depends on the optical detector s dark current the value it measures with no light applied The DCA can compensate for tem perature or time related dark current drift Use the following procedure Remove any optical signal from the optical input a
66. hod Measurements Non Return to Zero Mode Measurements Deterministic Jitter Deterministic Jitter is a measure of data dependent jitter Deterministic Jitter Rise 14 7 ps Fall 1 8 ps Click Deterministic Jitter on the left hand side of the display FGNRZDeterministicJitterAPI MeasNRZDeterministicJitterRise MeasNRZDeterministicJitterFall 5 34 Measurements Non Return to Zero Mode Measurements Crossing Hist Shows the distribution of samples at the crossing point Control Panel Click Crossing Hist on the left hand side of the display API Call N A Active X Method N A 5 35 Measurements Non Return to Zero Mode Measurements ISI Histogram Shows the distribution at the crossing points for LLH HLH HHL and LHL pat terns separately 0 012 UI Center 4 1 ps 0 017 UN Control Panel Click ISI Histogram on the left hand side of the display API Call N A Active X Method N A 5 36 Measurements Eye Mask Test Mode Measurements Eye Mask Test Mode Measurements The N2100A allows the Host Application to select an eye mask and also to per form a comparison of the acquired NRZ Eye against the selected eye mask Pass Fail If any sample points fall inside either the mask or the mask margin the test fails for positive mask margins For negative margins only points that fall within the mask itself original mask minus margin fail Fibre Channel mask 10 margin Tektronix
67. host simulator Instrument ID Strine PXI2 13 INSTR Scan for Instruments 5 Select PXI bus 6 Click Scan for Instruments and select the appropriate DCA instrument ID String J Click OK When multiple DCAs are present in the chassis use NI Measurement and Automation Explorer NI MAX to determine which DCA is in which chassis slot before selecting one 8 On the Control Panel click Connect A message panel will appear AAR briefly as the connection is established and will then disappear 3 3 Using the Control Panel To perform a quick confidence check To perform a quick confidence check 1 Apply an appropriate signal to either the optical or electrical input connector and configure the instrument accordingly NOTE Connecting optical and electrical inputs at the same time results in erroneous measurements 2 Select the Module Config button Module Confia 3 Select the Line Rate the clock recovery mechanism the Input Path and Filter if applicable 4 Click Start Acquisition The N2100A is functioning correctly when you can see an eye diagram as shown in the following figure PX2000 333 Configuration Settings Global Parameters LineRate Mb s 42500 x Custom Line Rate pss o Opt Wavelength 50m Opt Attenuation po eS Elect Attenuation foo et Reference Clock Recovered Ne Extemal Reference Freq MHz v 128 0 Time Base Wander Correction Off X DCA Parame
68. ign colors so that each color cov ers the same number of bins which results in every sample being displayed in the higher frequency of occurrence colors See below on the left hand side 3 15 Using the Control Panel Settings on the Density Display tab Or you can assign each bin a separate color until one runs out of colors result ing in the highest sample densities being displayed very prominently An intermediate setting gives results that are probably the most appealing which results see below right ruber l Ld Choosing a color scheme This implementation offers three schemes two sets of colors and one prima rily using intensity levels to distinguish between sample densities The pic tures above use a color scheme in which blue and violet represent the highest sample densities The other color based scheme assigns orange and yellow to the highest densities and the intensity based scheme uses only green and blue 3 16 Using the Control Panel Settings on the Density Display tab Threshold display One further display variant uses two colors and a single adjustable density threshold Display wth threshold 5 Display with threshoki 12 Contrast adjustment It is sometimes desirable to display the samples with high frequency of occur rence most prominently In this implementation Contrast controls adjust the pixel intensity with greatest effect on the low density colors least effect on the high den
69. igure 4 7 Select Mask Dialog Box With none of the checkboxes checked the mask will be center only and will be rectangular based on x2 x8 yl y2 Checking Mask uses x1 x4 adds two additional points allowing the center mask to be defined as a hexagon Checking Mask used x5 x6 y5 y6 adds four addi tional points allowing the center mask to be defined as a decagon Checking Mask uses y3 y4 adds the top and bottom mask definitions A validity check is performed on the coordinates before values are accepted One or more pop ups appear if there is an inconsistancy in specifying the mask parameters The user must acknowledge this test before proceeding with such values Control Panel Measurement Modes How the Mask and Mask Margin are defined The Margin Compatibility option gives you the choice between choosing a mask that applies the margin based on either the Agilent rule or the Tektronix rule Mask H1 User Defined Mask z Mask Margin Margin Compatibilit SP 50 Tektronix si Lance IV Mask uses X1 Xue Pern Y5 Y6 M Mask uses Y3 Y4 Figure 4 8 Margin Compatibility Option 4 12 Control Panel Measurement Modes Agilent Mask Margins Rules Agilent Mask Margins Rules When a positive margin is applied vertices of the inner mask are moved by the requested proportion towards the left and right crossing points and towards the top and base levels The parameters x2 and x4 however remain constant The Top ma
70. instrument is still under warranty or is covered by an Agilent maintenance contract it will be repaired under the terms of the warranty or contract If the instrument is no longer under warranty or is not covered by an Agilent maintenance plan Agilent will notify you of the cost of the repair after examining the unit When an instrument is returned to an Agilent service office for servicing it must be adequately packaged and have a complete description of the failure symptoms attached When describing the failure please be as specific as possible about the nature of the problem Include copies of any instrument failure settings data related to instrument failure and error messages along with the instrument being returned Please notify the service office before returning your instrument for service Any special arrangements for the instrument can be discussed at this time This will help the Agilent service office repair and return your instrument as quickly as possible Call Center For technical assistance contact your local Agilent Call Center In the Ameri cas call 1 800 829 4444 In other regions visit http www agilent com find assist Before returning an instrument for service you must first call the Call Center at 1 800 829 4444 Preparing the product for shipping Write a complete reason for returning the product and attach it to the instrument Include any specific performance details related to the problem Pack
71. inwards if the margin is negative In Error Reference source not found this is represented as AX Min AX AX 4 15 Control Panel Measurement Modes Tektronix Mask Margins Rules For the center mask the available margin in the Y amplitude dimension AY o is the smaller of the distance from the signal base level Y to the lower mask edge and the distance from the upper mask edge to the signal top level O AY o Min AY AY Note that Y and Y can be defined relative to the full UI values or a specified window p about the center of the eye The upper and lower edges of the center mask are moved outwards by the speci fied percentage of this available margin or inwards if the margin is negative The dotted lines represent the mask margin while the full straight mask lines represent the original mask For the upper lower masks the available maring in the Y dimention is the distance from the mask level to the top base level These masks are moved by the specified percentage of this available margin toward the center mask if the margin is positive or away if the margin is negative The Tektronix margin definition requires that the upper and lower mask regions be present and that the center region is defined to be between the base and top levels the upper and lower regions outside of these levels For the 6 or 10 point mask case all intermediate points are moved in propor tion to their distance from the mask
72. ition types separately 5 17 Control Panel API Call Active X Method Measurements Non Return to Zero Mode Measurements Extinction Ratio Ratio of the On optical level High to the Off optical level Low measured within the NRZ window The result is expressed as Ratio dB and Percentage These are calculated using the following formulae _ High ER patio Low ER 1010872 _ High Low ERy High x 100 Extinction Ratio 6 2 15 82 dB 83 8 Click Extinction Ratio on the left hand side of the display FGNRZExtinctionRatioAPI MeasNRZExtinctionRatio MeasNRZExtinctionRatioDB 5 18 Measurements Non Return to Zero Mode Measurements Extinction Ratio with histogram This displays the same results as the Extinction Ratio measurement addition ally it displays the distribution of sample points within the NRZ window using a histogram Extinction Ratio 6 2 15 82 dB 83 8 Control Panel Click Ext Ratio Hist on the left hand side of the display API Call N A Active X Method MeasNRZExtinctionRatioHist MeasNRZExtinctionRatioDBHist 5 19 Measurements Non Return to Zero Mode Measurements Eye Height Difference between the 3 sigma value of the high samples within the NRZ window and the 3 sigma value of the low samples within the NRZ window Eye Height is the vertical opening of the eye Eye Height Prop 3Oop Phase 2 pase Eye Height 392 9 mv Control
73. l invoke the Select Mask dialog box shown below This is used to select from a set of industry standard masks or to create a cus tom mask for specific user requirements The predefined masks are listed in Table 4 1 on page 4 9 Fibre Channel 1x Mask Margin Margin Compatibility Cancel o Agilent zl paat IV Mask usesX1 x4 I Mask uses X5 x6 Y5 YG IV Mask uses Y3 Y4 Mask Y levels are relative to jo of eye x4 0 785 ESS xa 0 600 L t dE i oa oa y2 jaso yo aso ya 1 300 ye 0 000 Figure 4 5 Selecting a Mask Industry Standard or User Defined The Copy Another Mask button allows for easy creation of custom user masks by using an existing mask whether it is a standard one or a previously defined user mask as a starting template The new Mask can is saved under a different mask number after clicking OK 4 8 Table 4 1 DCA Predefined Mask Definitions Control Panel Measurement Modes Mask Selection Industry Standard and User Defined Win MASK x1 x2 x3 x4 x5 x6 y0 y1 y2 y3 y4 y5 y6 dow stm 1 0 15 0 35 0 65 0 85 0 5 0 2 0 8 Full UI stm 4 0 25 04 0 6 0 75 0 5 0 2 0 8 Full UI stm 16 0 4 0 6 0 5 0 25 0 75 Full UI Gb Ether 0 22 0 375 0 625 0 758 0 5 0 2 0 8 0 2 1 3 20 net Fibrechan 0 215 0 4 0 6 0 785 0 5 0 2 0 8 0 2 13 20 nel 1x Fibrechan 0 22 0 4 0 6 0 78 0 5 0 2 0 8 0 2 13 20 nel 2x 4x 4 9 Control Panel Measurement Modes How the Mask and Mask Margin ar
74. lors 2 Orange and yellow represent the highest sample densities Intensity Different intensities of blue and green represent different densities Single Threshold A two color display with adjustable density threshold Signal View the Eye Diagram Display Density Distribution View a Histogram of the samples 3 13 Resolution Color Intensity Display Threshold Display Sample Density Display Information Using the Control Panel Settings on the Density Display tab A control that selects the quantization grid used to assign sample densities Moving the slider to the left selects a coarser grid to the right selects a finer grid Contrast adjusts the intensity of the low density pixels Weighting controls the assignment of display colors to bins Moving the slider to the right makes high density samples relatively more prominent Contrast adjusts the intensity of the pixels used to display densities below the threshold Threshold sets the display threshold An up down button control gives a fine adjustment of this value The DCA sample density display is a software tool which enables the Control Panel application s eye diagram to display colors based upon the population of sample values For example samples acquired by the DCA make up the typi cal eye single color diagram shown on the left Or multi color pixels based on the types of transition to which the samples belong in the middle In simplified description the n
75. ly Do not apply bending force to connection Do not over tighten preliminary connection Do not twist or screw in connectors Use a torque wrench and do not tighten past the break point of the torque wrench 3 5 mm and SMA Connectors Precision 3 5 mm microwave connectors are compatible with an SMA connec tor within its specification Due to the variable quality of the SMA connector mating with an SMA can sometimes cause severe damage to the 3 5 mm con nector You can use SMA connectors if special care is taken when mating the connectors and all connectors are undamaged and clean Before each use check the mechanical dimensions of all connectors with a connector gauge to make sure that the center conductors are positioned correctly A male SMA connector pin that is too long can smash or break the delicate fingers on the precision 3 5 mm female connector Some precision 3 5 mm female connector fingers are very tight and can pull the center pin of their mates out past specifications when the connectors are disconnected If such a male pin is inserted into a female connector it can cause considerable damage by pushing the female center conductor back too far Be aware of this possibility and check all connectors before mating them again 1 8 General Information Optical Connectors Optical Connectors Taking care of fiber optic connectors is critical to making quality measure ments Because fiber optic connectors are suscepti
76. nd cover the connector Click Module Cal on the Control Panel Click Measure Dark Current The DCA measures and stores the dark current measurement This is relevant to extinction ratio and optical power measurements For increased accuracy of these values a dark current calibration should be performed regularly The System Log button can be used to view the log of system errors and events The information collected depends on the Logging Level selection Logging Level None Nothing is logged Logging Level Fatal Only fatal errors are logged Logging Level Error All errors are logged Warning All errors and warnings are logged Logging Level Info Errors warnings and other events are logged Logging Level Debug Errors warnings and internal information used for firmware debugging are logged 3 26 Using the Control Panel Calibrating the N2100A Application Log This log is associated with application level firmware func tions System Log This log is associated with system level driver functions Read Log Pressing this button will cause the appropriate log file to be dis played using Notepad The file will be deleted unless the Keep File checkbox is checked Clear Log Use this button to clear the appropriate log The Allow Clear checkbox must be checked for this to be available The logging setting should be set to Error Fatal or None in normal use Other wise the performance speed of the DCA will be affected
77. on fibers remain on the fiber end after cleaning Clean the ferrules and other parts of the connector while avoiding the end of the fiber 3 Apply isopropyl alcohol to a new clean lint free cotton swab or lens paper CAUTION General Information Optical Connectors Clean the fiber end with the swab or lens paper Do not scrub during this initial cleaning because grit can be caught in the swab and become a gouging element Immediately dry the fiber end with a clean dry lint free cotton swab or lens paper Blow across the connector end face from a distance of 6 to 8 inches using filtered dry compressed air Aim the compressed air at a shallow angle to the fiber end face Nitrogen gas or compressed dust remover can also be used Do not shake tip or invert compressed air canisters because this releases particles in the can into the air Refer to instructions provided on the compressed air canister As soon as the connector is dry connect or cover it for later use If the performance after the initial cleaning seems poor try cleaning the con nector again Often a second cleaning will restore proper performance The second cleaning should be more arduous with a scrubbing action General Information Returning the N2100A to Agilent Returning the N2100A to Agilent The instructions in this section show you how to properly package the instru ment for return to an Agilent Technologies service office If the
78. opriate caution when using Agilent products for testing lasers 1 3 WARNING NOTE General Information Introduction Laser Safety Notice The N2100A is used to measure optical signals When connecting and disconnecting optical cables or equipment all optical sources MUST be disabled Failure to take proper safety precautions may result in eye damage All un used optical ports MUST be covered when not in use to prevent light leakage or contamination This product complies with the Electrostatic Discharge immunity requirement in IEC EN 61326 using performance criterion B Degradation of some product specifications can occur during the instance of an electrostatic discharge The product self recovers and operates as specified after the discharge 1 4 General Information Electrostatic Discharge Information Electrostatic Discharge Information CAUTION Electrical channel input circuits and the trigger input circuit can be damaged by electrostatic discharge ESD Therefore avoid applying static discharges to the front panel input connectors Prior to connecting any coaxial cable to the connectors momentarily short the center and outer conductors of the cable together Avoid touching the front panel input connectors without first touching the frame of the instrument Be sure that the instrument is properly earth grounded to prevent buildup of static charge Wear a wrist strap or heel strap Electrostatic dis
79. perating a mode Lo Dury Cycle Diet Measurements Markers Using the Control Panel Introduction Introduction This chapter describes how to start and configure the Control Panel For infor mation on controlling the five measurement modes from the Control Panel refer to Chapter 4 Control Panel Measurement Modes All aspects of the N2100A can be controlled through the Control Panel Use the top row of buttons to configure the module I O and connect to the mod ule The mode of operation of the N2100A is controlled using the list box in the top left corner of the main form PX2000 333 Not Connected Row of Stat Acquistion M Repetitive Module Contig Frog Settings 10 Config Data configuration z Sasi Medule Ca Coop Giach Cop Tort buttons Eya Ampkude Clipboard Eye idih ana copy Low Hih Sigalto Noise Brae _FiseTire aa Costing Pct Single Edge Jita Craasing Hist C X Histogram Y Histog am Measurements results area Figure 3 1 Control Panel Using the Control Panel To start the Control Panel To start the Control Panel 1 Click the Window s Start menu 2 Click All Programs PXIT and then PX2000 333 3 Click PX2000 333 Control Panel 4 Click I 0 Config to open the Set Module I O Address dialog box which is used to configure communications between the host controller and the instrument Set Module 1 0 Address X Interface TCPAP PXI Bus C Local
80. re is applied Enabled No filter In this mode the DCA performs a pattern capture but does not apply any filtering Any Specific filter With this option selected the DCA performs a pattern cap ture and then applies the selected digital filter to this pattern Only files with valid names and stored in a specific folder are made available for selection The Pattern control used to specify the length of the repeating pattern sequence has selections for PRBS 27 1 PRBS 29 1 PRBS 211 1 K28 5 K28 7 and Set Length for patterns of arbitrary length When Set Length is selected the field to the right is enabled in which the pattern length should be entered The length must be between 4 and 2047 Used to select threshold levels when calculating Rise amp Fall times Choices are 10 to 90 20 to 80 and 30 to 70 of either the total Waveform Ampli tude Full Period or the NRZ Windowed high and low values Selects the percentage of the UI width that is used for NRZ measurements 3 8 Using the Control Panel DCA Parameters OMA Window Size Selects the percentage of the UI width that is used for OMA measurements 3 9 Refresh Apply Show Version Set Defaults Set IP Addr Presets Using the Control Panel Additional Controls Additional Controls Cancels unapplied changes on screen and restores to actual DCA configura tion Available when changes have been made Sends new configuration to DCA
81. s 3 30 API 7 3 Average Optical Power 5 15 B Base 5 7 Bit Rate 5 27 C Calc Stats 4 17 cleaning fiber optic connections 1 13 non lensed connectors 1 13 Color Intensity Display 3 14 compressed dust remover 1 13 Configuration Settings 3 6 Connect 3 3 Control Panel 3 2 Copy Another Mask 4 8 cotton swabs 1 13 Count 3 19 Crossing Hist 5 35 Crossing Histogram Window 3 13 Crossing Percentage 5 30 custom user masks 4 8 D DCA Parameters 3 7 Deterministic Jitter 5 34 dimensions 8 3 Disconnect 3 5 Display Background 3 12 Display Colors 3 11 Display Traces 3 12 DLL 7 2 Duty Cycle Distortion 5 31 E Edge Jitter 5 32 electrostatic discharge 1 5 Environmental Specifications 8 3 Extinction Ratio 5 18 Extinction Ratio with histogram 5 19 Eye Amplitude 5 21 Eye Diagram 5 3 Eye Height 5 20 Eye Mask Test Mode Measurements 5 37 Eye Width 5 22 eye diagram analysis 5 2 F Failing Points 4 7 Fall Time 5 29 Filter File Format 3 24 Filter Files 3 24 Find Max Margin 4 7 Find Max Margin 5 38 Firmware 3 33 floor mat 1 5 foam swabs 1 13 G Global Parameters 3 6 H heel strap 1 5 High 5 25 I ID String 3 3 industry standard masks 4 8 Inspect 2 2 install 2 2 instrument returning for service 1 15 ISI Histogram 5 36 L asers 1 3 Load DCA File 6 2 Low 5 24 M Margin Compatibility option 4 12 Markers 4 4 Mask Definitions 4 9
82. s basic deterministic jitter measurement Transition 2 Slow measures the average jitter between rising transitions Lengh 2 x 001 transition following a steady low and 101 transi c jon tion following a transition and between falling transi tions 110 and 010 In comparison this measurement measures the average jitter between two specified Updat transition sequences up to 16 bits in length Jee C All In this context Fast refers to the transitions normally called HLH and LHL Slow to LLH and HHL These controls allow redefining these transitions with arbitrary bit sequences for the purposes of this mea surement For example a sequence consisting of a low to high transition pre ceded by exactly four low states would be expressed as 100001 For the Slow transition the Length selector refers to the number of low states preceding a rising transition or the number of high states preceding a falling transition The sequence 1001 corresponds to length 2 and the sequence shown above corresponds to length 4 Results of these measurements are reported as follows D J 1001 to 101 Rise 7 3 ps Fall 4 3 ps The eye display changes so that the only transition samples shown are those that match the specified patterns If display colors are enabled these are shown in the corresponding transition colors 4 19 Control Panel Measurement Modes Pattern Sequence D J Mode When the All choice is selected the measurement is m
83. s common between the embedded firmware and the host library This header file contains all the status codes used by the PX2000 333 This header file contains all the data structures that make up the API between the Host Application Host Library and embedded firmware The interface between the OEM application and the PX2000 333 is packet based A directory of API examples is included with the downloaded software and drivers the default location for this folder is C Program Files PXIT PX2000 333 examples 7 2 Programming API Structure The Include and lib folders of examples are stored here API Structure The API is provided in the form of a Windows based DLL and an Active X con trol These allow control of the PX2000 333 DCA The API allows the host application to Create and delete communication channels to the PX2000 333 instruments Receive notification for status change Perform data acquisitions Configure the PX2000 333 Perform measurements Perform eye mask testing 7 3 Programming API Structure Host Application Any application that supports C or C Active X Controls e g VB LabView LabWindows Host Application pote API Calls PXIT333AXC Active X Low Level f DCA API Calls interface to DC Vv DCA Host Interface Library DLL Command Command Response Packets Response Packets over TCP IP over PXI bus Windows TCP
84. s of the average of LL samples during the interval defined by the window Low 133 5 mY Click Low onthe left hand side of the display FGNRZLowAPI MeasNRZLowLevel 5 24 Measurements Non Return to Zero Mode Measurements High Is measured within the NRZ window measures of the average of HH samples during the interval defined by the window High 654 4 m Control Panel Click High on the left hand side of the display API Call FGNRZHighAPI Active X Method MeasNRZHighLevel 5 25 Measurements Non Return to Zero Mode Measurements Signal to Noise Ratio Ratio of the signal difference between high level and low level relative to the noise present at both levels Signal to Noise Ratio 10 5 Control Panel Click Signal to Noise on the left hand side of the display API Call FGNRZSNRAPI Active X Method MeasNRZSNR 5 26 Measurements Non Return to Zero Mode Measurements Bit Rate For the Recovered External Internal clock selections this measurement returns the line rate set For Internal Auto and External Auto it returns the value that result in the maximum eye width Bit Rate 1250 0000 Mb s Control Panel Click Bit Rate on the left hand side of the display API Call FGNRZBitRateAPI Active X Method GetBitRate 5 27 Measurements Non Return to Zero Mode Measurements Rise Time The measurement is made on the rising edge between the thresholds selected by the NRZ Threshold confi
85. sity colors These examples show the effect of the contrast adjustment 3 17 Using the Control Panel Settings on the Density Display tab 3 18 Using the Control Panel Acquiring Data Acquiring Data After configuring the module and the Control Panel click Start Acquisition Start Acquisition to begin acquiring data In the Control Panel you can select Repetitive to have continuous acquisitions as shown in the fol lowing figure Start Acquisition Iv Repetitive Module Config Prog Settings 1 0 Config Data Disconnect a fico Modul Mask Tests ka jodule Cal Copy Graph Copy Text Figure 3 3 Repetitive Selected Select Repetitive and Count to specifiy a number of acquisitions to acquire In the following figure the count is set to 100 A progress bar indicates how many acquisitions have been done and what is left Repetitive Module Config Prog Settings 1 0 Config Data Disconnect M Count 100 Mask Tests X hero Module Cal Copy Graph Copy Text NSN Figure 3 4 Count Selected with Progress Bar progress bar Use the General tab of the Program Settings dialog box to con figure the repetitive results text Select Overwrite and during a hiepeivo repetitive acquisition sequence each measurement is overwrit 2 Overwrite C Add ten by the subsequent measurement on the display Select Add E AddTime and each measurement is added to form a list of measurements l ves am on the display Select
86. sk region y4 moves down toward the top level and the bottom mask y3 moves up towards the base level in proportion to margin Measured Top Level Margin B A x 100 Original Mask Mask with Margin Measured Base Level Figure 4 9 Agilent Mask Positive Margin For negative mask margins all points in the center mask are moved in towards the center by the requested proportion the Top and Bottom masks are moved away from the top and base levels by the requested proportion 4 13 Control Panel Measurement Modes Agilent Mask Margins Rules Top and Bottom Margin B A x 100 4 ae Top Level Original Mask Mask with Margin Measured Base Level Figure 4 10 Agilent Mask Negative Margin 4 14 Control Panel Measurement Modes Tektronix Mask Margins Rules Tektronix Mask Margins Rules In the Tektronix mask margin conventions the available margin in the X time dimension AX is the smaller of the distance from the left eye cross ing to the leftmost mask vertex and the distance from the rightmost mask ver tex and the right eye crossing Y Y 2 AY Note Y Y Based on High Low F0 5UI AX o9 Min AX AX samples over center p of Eye AY jo9 Min AY AY Figure 4 11 Tektronix Rectangle Mask Margin Illustration The leftmost and rightmost vertices of the center mask are moved outward by the specified percentage M of this available margin or
87. ssible to other applications Applications can access other applications functionality through standard interfaces A loosely defined set of technologies developed by Microsoft for sharing infor mation among different applications ActiveX is an outgrowth of two other Microsoft technologies called OLE Object Linking and Embedding and COM Component Object Model ActiveX can be complicated because it applies to a whole set of COM based technologies Most people however think only of ActiveX controls which represent a specific way of implementing ActiveX technologies ActiveX controls are among the many types of components that use COM technologies to provide inter operability with other types of COM components and services Agilent provides the software interface to the DCA implemented as an Active X control that can be called according to standard conventions by applications written in Visual C Visual Basic LW CVI etc The control provides access to the module API functions and optionally provides the same eye display as the GUI 7 7 Programming Active X 7 8 Specifications Specifications Specifications Specifications The distinction between specifications and characteristics is described as fol lows Specifications describe warranted performance over the temperature range 0 C to 40 C and relative humidity lt 95 unless otherwise noted All speci fications apply after the temperature of the
88. tained its polished smoothness the connector can still provide a good low level return loss con nection If you test your cables and accessories for insertion loss and return loss upon receipt and retain the measured data for comparison you will be able to tell in the future if any degradation has occurred Typical values are less than 0 5 dB of loss and sometimes as little as 0 1 dB of loss with high performance con nectors Return loss is a measure of reflection the less reflection the better the larger the return loss the smaller the reflection The best physically contacting connectors have return losses better than 50 dB although 30 to 40 dB is more common Visual inspection of fiber ends can be helpful Contamination or imperfections on the cable end face can be detected as well as cracks or chips in the fiber itself Always remove both ends of fiber optic cables from any instrument system or device before visually inspecting the fiber ends Disable all optical sources before disconnecting fiber optic cables Failure to do so may result in permanent injury to your eyes Cleaning Non lensed Connectors CAUTION CAUTION General Information Optical Connectors Use a microscope 100X to 200X magnification to inspect the entire end face for contamination raised metal or dents in the metal as well as any other imperfections Inspect the fiber for cracks and chips Visible imperfections not touching the fib
89. ters Sample Blocks iB Input Path and Filter Optical Nofiter gt Pattern Acquisition jor o SY Pattern PRBS 2 7 1 i NAZ Thresholds 20 to 80 Full period NRZ Window Size 10 OMA Window Size f2 Refresh Show Version Set Defaults Set IP Addr EE E Beek HL Start Acquisition 3 4 Using the Control Panel Powering Off the Instrument 1000 If the input signal timing cannot be locked the follow message is displayed Timing System Out of Lock Warning The sample clock is not locked to the applied signal or reference clock so the data acquired is not valid If you are using an external reference clock the reference frequency may be set incorrectly or the applied reference signal may be different from its expected value If you are using recovered clock the line rate may be set incorrectly or the rate may differ from its expected value Do not show this message again Powering Off the Instrument Click Disconnect Close the Control Panel Soft power down the PC Switch off power to PXI chassis 3 5 Line Rate Mb s Custom Line Rate Opt Wavelength Using the Control Panel Module Configuration Settings Module Configuration Settings The Configuration Settings dialog box is used to set up the operating parame ters The current DCA configuration appears in this panel when first displayed and any time the Refresh Button is pressed Changes made on
90. their X value i e their time position within the eye Trans sorts the samples based on what type of transi 3 28 Copy Graph Button Copy Text Button Using the Control Panel Copying and Saving Displayed Test Results tion they belong to within transitions samples are sorted based on X value With the Fail selection mask fail points are put at the top of the list Within the pass and fail group s samples are sorted based on X value Click Copy to copy the data to the clipboard Click Save to save the data to a file The transition selection button All displays all transitions Click Sel d and only transitions selected using the transition buttons LLL LLH LHH HHH will be displayed These transition buttons allow individual transitions to be switched on or off Select Y Values and all qualifying samples will be included in the data Mid 40 specifies that only samples that fall in the middle 40 of amplitude read ings will be included Samples displays the individual data samples while Pat tern Hex displays the reconstructed pattern sequence in hexadecimal format pattern acquisition only Pattern Bin displays the reconstructed pattern sequence in binary format pattern acquisition only When the data is aquired with a mask test pattern sequence bits containing samples that fail the mask test are underlined in the display The Copy Graph button copies the graph and all the text data from the most recent acquisi
91. tion following a sustained low state LHL High to low transition following a low to high transition LHH Sustained high state following a low to high transition HLL Sustained low state following a high to low transition HLH Low to high transition following a high to low transition HHL High to low transition following a sustained high state HHH Sustained high state following a sustained high state 6 8 Introduction 7 2 Software File Structure 7 2 API Structure 7 3 Establishing Communications with the PX2000 333 7 5 Controlling the DCA from a User Written Test Program 7 6 Active X 7 7 Programming fghostapi dll fghostapi lib fghostapi h fgtypes h fgstatus h fgapidefs h Programming Introduction Introduction Refer to Module Configuration Settings on page 3 6 for details of the config urable parameters Refer to Chapter 5 Measurements for details of the con figurable parameters See the separate PX2000 333 DCA Programmer s API and Active X Control Guide for a detailed description of the API Software File Structure The PX2000 333 Host Library consists of the following software components This file is the Windows based DLL that implements the Host Library API This file contains all the DLL exported functions that are linked against the Host Application This header file contains the Host library function prototypes and definitions This header contains data type definition
92. tion run as displayed on the screen The image is available as an object on the PC clipboard and may be pasted into a word processing program for future use The Copy Text button copies all the information from the results display win dow in text format This information can be pasted into any program such as MS Word or Notepad as in this example Meas Average Minimum Maximum Std deviation Amplitude 420 637 407 250 429 750 12 222 Peak to peak 514 087 491 250 528 563 15 871 RMS 197 393 190 520 201 963 6 251 Average 384 790 384 553 384 977 0 178 OMA 419 203 404 144 429 215 13 435 3 29 Using the Control Panel Copying and Saving Displayed Test Results Custom Annotations You can annotate the graph image caption Hold down the keyboard s CTRL key while clicking Copy Graph or Copy Text This displays dialog box shown in Figure 3 9 The buttons and text entry field provide a way for the user to append additional text to the visual or textual data captured as shown in Fig ure 3 10 on page 3 31 Annotate Graph Image Caption Text position Insert Date and Time Insert text before results data Insert text after results data _Insert Module Conti C Replace results data with text Insert Current Mask pit 7 Insert Version Info Text to add to image caption Fri Aug 11 2006 12 45 54 Line rate 2488 32 Optical Wavelength 1550 nm Optical Atten 0 0 dB Electrical Atten 0 0 dB Reference Clock Recovered Reference Freq 10
93. ts Oscilloscope Mode Measurements Positive Overshoot The difference between the maximum sample value and the signal s top level expressed as a fraction of the signal amplitude Max Top x Top Base see Positive Overshoot Positive Overshoot 13 9 Control Panel Click Pos Overshoot on the left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscPosOvershoott 5 13 Measurements Oscilloscope Mode Measurements Negative Overshoot The difference between the minimum sample value and the signal s base level expressed as a fraction of the signal amplitude Base Min Top Base a Negative Overshoot Negative Overshoot 22 4 Control Panel Click Neg Overshoot on the left hand side of the display API Call FGDCAOscilloscopeAPI Active X Method MeasOscNegOvershoot 5 14 Control Panel API Call Active X Method Measurements Oscilloscope Mode Measurements Average Optical Power Applicable to optical signals only The true average component of an optical signal expressed in microwatts or dBm decibels relative to a power level of one milliwatt This measurement results from the use of a hardware average power monitor circuit rather than from the calculation of digitized waveform data Click Ave Power on the left hand side of the display FGDCAAvgPowerAPI MeasAvgPowerUW MeasAvgPowerDBM 5 15 Measurements Non Return to Zero Mo
94. uch as the NI MXI 4 prod uct If an external PC is used the PC must meet the following specification e Windows 2000 or XP operating system e 128 MB RAM e Pentium 133 MHz or greater When using an external PC if the sequence of the following installation steps is not followed the PC BIOS will not be able to locate the instruments in the PXI chassis Your new N2100A is compatible with the current version of the control panel software If your PXI chassis includes older N2100A PX2000 333 DCA instruments you may need to upgrade the instrument s firmware as described in Upgrading the Instrument s Firmware on page 3 33 Step 1 Inspect the Shipment Inspect the shipping container and kit for damage Keep the shipping container and cushioning material until you have inspected the contents of the shipment for completeness and have checked the kit mechanically and electrically Locate the shipping list Verify that you have received all of the items listed To contact Agilent Technologies for technical assistance contact your local Agilent Call Center In the Americas call 1 800 829 4444 In other regions visit http www agilent com find assist Before returning an instrument for service you must first call the Call Center at 1 800 829 4444 Do not install the N2100A in the PXI chassis at this time Ensure that the PXI chassis is connected to the specified power source using the correct power cord noting country o
95. w High Signal to Noise Bit Rate Rise Time Fall Time Crossing Pet Duty Cycle Dist Edge Jitter Single Edge Jitter Deterministic Jitter Crossing Hist ISI Histogram Markers Off X Histogram C On YHistogram Repetitive Module Cfg 1 0 Config Data Disconnect as Module Cal Acquiring 1400 1200 101 Copy Graph Copy Text Eye Width 228 ps Ratio 0 970 Figure 4 2 NRZ Measurements Mode 4 5 Control Panel Measurement Modes Mask Tests Mode Mask Tests Mode Use Mask Test mode determine whether the signal meets defined mask requirements and to calculate how much margin there is before failure Select ing a Mask is done by clicking Select Mask Select mask Start Acquisition Repetitive Module Config Prog Settings 1 0 Config Data Disconnect J Mask Tests Ei Module Cal Copy Graph Copy Text Acquire Mask test pass Select Mask Failing Points Find mask E margin for eer k s or maximum failed points 400 failing points User selected mask margin 0 margin mask Calculated mask margin Mask margin for 386 failing points 69 Markers Off X Histogram C On Y Histogram Failed points Figure 4 3 Mask Tests Mode 4 6 Failing Points button Find Max Margin button Control Panel Measurement Modes Mask Tests Mode In Failing Points the software reports any points that fall in th
96. will set the closet pair of offset and scale settings to zoom within the area selected by the markers The amplitude values are displayed along the Y axis with the units on top Turning on the Markers control displays a pair of movable markers in both X and Y The histogram function displays a histogram of the samples within the region bounded by the markers selectable over X or Y values Markers can be repositioned using the mouse The Marker is selected with the left mouse button and moved by dragging the mouse Holding down the shift key while moving the mouse will lock the two markers so that the distance between them is preserved The markers can also be used to control the scale of the display The normal view UD presents the view of two UI Switching to the Set option in the X Axis control allows you to zoom in and out on the eye diagram In Y Axis Auto mode the signal amplitude is scaled to best fit within the display screen The Set option allows the user to zoom in and out 4 4 Control Panel Measurement Modes NRZ Measurements Mode NRZ Measurements Mode NRZ Measurement Mode offers a selection of signal and timing measurements typically associated with NRZ signals Re acquisition of data is not required For information on NRZ measurements refer to Chapter 5 Measurements Start Acquisition J NRZ Measurements v Extinction Ratio Ext Ratio Hist Eye Height Eye Amplitude fer AS WEED OMA Lo

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