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Multitone Audio Test System

1. LINK ON SYNC INTERNAL DEEMPHASIS ON TRIGGER CONFIGURATION LOOSE v INPUT1 STAT RANGE 1 0000E1 Vp SWFILTER OFF FRONT ON LINK OFF SYNC EXTERNAL DEEMPHASIS ON TRIGGER CONFIGURATION TIGHT UM in NEUTRIK CORTEX INSTRUMENTS 48 71 V 3 32 RTM Multitone Audio Test System User Manual OUTPut Subsystem OUTPut MTONe PARameter lt Parameter gt Use Parameter Range Query Example Explanation Defines a multitone signal lt Sig_Number gt integer target memory of RT 1M lt Sig_Name gt string user defined signal name lt No_Of_Samples gt integer blocklength lt No_Of_Bins_CH1 gt integer total number of bins set in channel 1 lt No_Of_Bins_CH2 gt integer total number of bins set in channel 2 lt Bin_X_CH1 gt integer bin numbers set in Chnl Bin X CH2 integer bin numbers set in Chn2 Phase X CHI1 float phases of bins set in Chn 1 Phase X CH2 float phases of bins set in Chn 2 Sig Number 1121314 Sig Number up to 8 ASCII characters no spaces allowed No Of Samples 5121102412048 1409618192 No Of Bins CH1 1 to31 No Of Bins CH2 1 to31 Bin No X CHI Bin Min to Bin Max Bin No X CH2 Bin Min to Bin Max Phase X CHI T to 7 Phase X CH2 T to 7 Big Min NoOSamples mn B
2. Fig 7 Unbalanced Connection Battery Low Indication amp 7 1 f contains a battery for backup purposes of the internal memories Life expectancy of the battery is about ten years Should the battery become low the Error LED will blink 3 to 4 four times after a start up and Error 220 Battery low memory backup is generated NEUTRIK CORTEX INSTRUMENTS V 3 32 13 71 RTM Multitone Audio Test System User Manual LED Indicators During the initialization period of system normally 1s all LEDs are active If the unit is switched ON for the very first time or after a firmware change it has to initialize all its signals and tables This might take up to a few minutes depending on the signal resolution All LEDs are lit during this period Power This LED indicates that the power of the system is switched on Power l the internal supply voltages are operating normally and the self O Interface test of the system has been successfully completed O Calculating O Trigger Should it stay off after switching on the instrument please check whether the power cable is connected to the system the voltage O Overload selector is set for the correct supply voltage and the wall socket is O Error e switched on Should the power LED still be off check the power fuse in the connector fuse holder assembly of 47 Please refer to AC Fig 8 LED Indicators Power Connection to see how to open it WARNING Do not tr
3. Service Request lt Status Byte Register Generation read by STB Logical OR Service Request Enable Register SRE lt NRf gt SRE For more detailed information refer to IEEE Std 488 2 1992 IEEE Standard Codes Formats Protocols and Common Commands Service Request clears RQS but not MSS NEUTRIK CORTEX INSTRUMENTS V332 65 71 RTM Multitone Audio Test System User Manual 5 APPLICATION HINTS T M is ideally suited to be integrated into industrial environments having virtually no switches and buttons All control is established through IEEE commands allowing to introduce Audio tests as a standard part of the entire QC procedure Arbitrary Generator With its flexibility ease of operation and its excellent price performance ratio 27 7 can be used as a simple arbitrary generator This way after few minutes of programming only 27 74 can serve as a sine wave generator with one fixed extremely stable frequency or as an IMD DFD or W amp F generator with two frequencies defined The four dual channel memory locations also allow to have all these configurations permanently stored Alignment and Adjustments for Audio Repair Facilities With the ability to plot two to three frequency responses every second alignment sequences for tapes where they have to be done manually or bias adjustments of amplifiers can be speeded up Repeated phase measurements simplify the alignment
4. Multitone Audio Test System Version 3 32 E For Firmware Revision 3 25 and higher V 3 32 Feb 99 ITI SVR1Wnstdatal RAPID TESTIRT 1MYU ManualltextRT 1M332 doc RTM Multitone Audio Test System User Manual NEUTRIK CORTEX INSTRUMENTS 2 71 V 3 32 RTM Multitone Audio Test System User Manual INTERNATIONAL WARRANTY Limited Warranty NEUTRIK guarantees the 4 system and its components against defects in material or workmanship for a period of one year from the date of original purchase for use and agrees to repair or replace any defective unit at no cost for either parts or labor Important This warranty does not cover damage resulting from accident misuse or abuse lack of reasonable care the affixing of any attachment not provided with the product loss of parts or connecting the product to any but the specified receptacles This warranty is void unless service or repairs are performed by an authorized service center No responsibility is taken for any special incidental or consequential damages In case of damage please take or ship prepaid your 47 System to your nearest authorized service center Be sure to include your sales invoice as proof of purchase date All transit damages that may eventually occur are not covered by this warranty Note No other warranty written or oral is authorized by NEUTRIK Except as otherwise stated in this warranty NEUTRIK makes no representation or warranty of any kind expressed
5. 3x Multitone duration of 42ms and consists of 5 fixed frequencies in the voice band with different levels By receiving this frequency level pattern a listening analyzer recognizes a 7 7 multitone signal and wakes up The pattern has been selected in a way that the false triggering rate due to voice music or other synthesized signals interpreted as multitone signal is lt 10 Time ms Fig 18 Multitone Signal with 5 Bursts as Example Additionally a pretrigger signal may be added in order to allow the DUT to stabilize before transmission of the rest of the multitone signal See also command OUTPut 1 2 LEVel lt Level gt lt Unit gt During the Clock Sync period SYNC block with a fixed length of 64ms the analyzer may adjust its sampling frequency to the transmitted clock frequency 3kHz This ensures that NEUTRIK CORTEX INSTRUMENTS V 3 32 25 71 RTM Multitone Audio Test System User Manual frequency shifts generated by the DUT modulators demodulators or tape machines with speed differences or slightly different clock frequencies of a separated generator analyzer pair are eliminated automatically Multitone Signal Right after the header information follows the multitone signal itself i e transmission of the signal bins The duration of the multitone signal depends on the block length as defined in Table 1 The multitone signal is transmitted at least 3 times and may be r
6. Furthermore no DTMF tone analysis will be possible in such a case NEUTRIK CORTEX INSTRUMENTS 34 71 V 3 32 RTM Multitone Audio Test System User Manual Broadcast Mode The broadcast mode allows to let the analyzer of a 27 14 unit wait for an incoming multitone burst that has been generated by another remote X7 1 unit generator A analyzer are physically apart By this it becomes possible to measure e g the characteristics of a transmission line Following restrictions have to be considered on behalf of the broadcast mode e The measurements under the broadcast mode can be done in one direction only at a time In order to return a multitone burst in the opposite direction e from the previously used analyzer to the generator the operation mode of both units has to be changed e The generator amp analyzer must be controlled each by a PC through a GPIB interface e The transmitted multitone signal must be defined identically on the generator amp analyzer e In order to avoid false triggering it is vital to thoroughly understand and apply the trigger configuration as well as the setting of a proper output level and input range in the generator and analyzer Mode of Operation The broadcast mode of 7 7 is based on the command INPut TRIGger ARMed f sent to the unit this instruction sets the analyzer to a state where it waits until it detects an incoming 47 7M trigger and receives the connected multitone signal T
7. This allows to transmit any command independently of the actual generator and or analyzer activities The instruction to transmit a previously defined multitone signal can be issued from the PC at any time Consequently the basic requirements for the host PC is a standard IEEE 488 interface board with installed software drivers Detailed descriptions of the IEEE 488 connection and all commands are filed in chapters Mains Cable and Programming respectively NEUTRIK CORTEX INSTRUMENTS V 3 32 9 71 RTM Multitone Audio Test System User Manual Accessories amp Options Software Tools Following software packages for are available free of charge from your local NEUTRIK representative e RT EVAL Evaluation Software e LabView Driver Library e LabWindows CVI Driver Library Please notice that for either of these tools a GPIB interface board from National Instruments type GPIB PCMCIA or GPIB TNT or GPIB PCIIA production year 1992 or later must be installed in your host controller Application Notes The appendix of this User Manual comprises the documents e Introduction to 27 14 e Get Familiar with Writing Code for amp f e Cellular Phone Testing e Comparison of Conventional vs Multitone Testing Additional application notes on speaker testing external signal analysis etc will be released in future Please contact you local NEUTRIK representative for further information DTMF Option Optional PCB to be i
8. allow the optimization of its phase relations The most suitable value for this purpose is the Crest factor which is defined as Peak Value Crest factor RMS _ Value Equation 1 Crest Factor For any multitone signal with given RMS value the Crest factor will change with the peak value which in turn depends on the phases of the signal components An optimal distribution of the phases results in a low peak value of the resulting time signal and therefore a low Crest factor refer also to chapter Phase Crest Factor Optimization NEUTRIK provides in its RT EVAL software package a sophisticated algorithm to optimize the phases of a multitone signal Please contact your local representative to get a free copy of this software Multitone Parameter T is a digital processing system that analyzes the transmitted signal by using Fast Fourier Transformation FFT and calculates with its DSP all desired results out of the digitized samples For proper use and programming of 7 7 it is vital to understand the core parameter of this analysis as well as their relationships Consequently the most important definitions and formulas are explained below Sampling Rate Every digitization process i e conversion of an analog signal into a digital bit stream and vice versa has to be accomplished at a certain sampling rate number of samples per second The sampling rate determines the analog bandwidth of the converter In 27 11 the samp
9. e they appear in the received signal of channel B and vice versa The crosstalk value is the ratio of the unused bin level in channel B and the active bin level of channel A at the same frequency It is expressed in or dB ye LEFT Unused _ Bin ChBi Set Bin Cha Crosstal Equation 15 Calculation of Crosstalk As an example we may assume that a signal bin with 10dB 1kHz is transmitted via channel A while at channel B the received bin level 1kHz equals 30dB Consequently the crosstalk from channel A to channel B 1kHz is 1 or 40dB Please note that noise increases the crosstalk value and thereby falsifies the measurement Amplitude Transmitted Transmitted Transmitted Signal Signal Signal Bin 1a Bin 2a Bin Xa Channel A Received Signal Bin 2b Frequency Hz 20 20k z Joa Amplitude Transmitted Transmitted P fna Signal Bin 1b Bin 2b I Channel B Received Signal Bin Xa Received Signal Bin 2a 1 Frequency Hz 20 20k Fig 23 Crosstalk Plot NEUTRIK CORTEX INSTRUMENTS V 3 32 33 71 RTM Multitone Audio Test System User Manual Phase Since the analyzer knows all information about the transmitted multitone signal from the generator also the phases of the signal bins are available for further analysis Therefore the analyzer may calculate any changes of inter channel phase relations at each common signal bin of
10. sre 32 ese 1 enable operation complete event output mtone par 1 telephon 8192 3 3 600 1000 3000 630 970 3030 0 0 0 0 0 0 opc gt B as soon as the calculation is finished RT 1M requests service SRQ by serially polling the controller Use of MAV bit in the status Byte register H sre 16 enable Output queue Not empty event output mtone start start measurement measi dist get distortion values oH as soon as the output queue has the valid distortion results RT 1M requests service SRQ via serial poll As soon as e g a SRE 16 has been sent to the unit 7 7 is set to the service request mode This means that 7 14 will send back a service request to the PC each time that it has a new message e g measurement result ready However please notice that this message may be transferred to the PC by serial polling only since Z7 24 cannot add any further information to the service request NEUTRIK CORTEX INSTRUMENTS 64 71 V 3 32 RTM Multitone Audio Test System User Manual IEEE Standard Status Data Structure e ui o E 5 8 3 ui 2 8 6 3 Rp R 3 5 Ka e o o o o Ka o 2 E 3 9 3 2 S 8 5 5 5 56 5 5 A z O E a E E O Standard Event Status Register ESR oc Y E S i Oo 4 o A Y Queue Ca Not Empty k S i i Standard n i Event Status i Enable Register Output Queue ESE lt NRf gt i ESE read by Serial Poll
11. 32 RTM Multitone Audio Test System User Manual Connections between an unbalanced DUT e and the balanced inputs of 27 14 should SE preferably be made with shielded twisted M 2 pair cables to avoid the introduction of Noground ierit Ee Q noise and hum The shield of such a cable shall be grounded only on one side Fig 4 Shielded Twisted Pair Cable Grounding the shield on both sides increases the chance to build ground loops Balanced Connection HI LO Fig 6 BNC Cable Balanced Fig 5 Balanced BNC Banana Connection Balanced connections with two BNC cables can be realized by connecting them to the Zi HIGH and LOW inputs The ground shells of both connectors are wired to ground Do not connect the shields together on the instrument side of the DUT but leave them open With balanced connections do not assemble the short circuit bar You may also use banana inputs instead of BNC inputs The respective HIGH and LOW inputs of the BNC and banana connectors are internally wired together Caution For balanced signals make sure that not only the front ground connection is disassembled but also the ground bar at the rear panel Unbalanced Connection If you use the HIGH input only of 7 7 for connecting the hot output of the DUT use the BNC cable s shield as the return signal common of the DUT output When using the generator in unbalanced mode the available level will always be 6dB 50 below the defined level
12. 71 V 3 32 RTM OUTPut MTONe NAME Multitone Audio Test System User Manual Use Queries the name of the active multitone signal Answer lt Name gt string Default the active signal name Example H Output mtone Name oH Telephon OUTPut MTONe BLOCklength Use Queries the number of samples i e blocklength of the active multitone signal Answer lt Blocklength gt integer Range 512 1 1024 i 2048 i 4096 8192 Example B gt OUTput MTONe BLOCklength gt B 2048 OUTPut MTONe PARameter Use Queries the parameter of the active multitone signal Format is compatible with the command OUTPut MTONe PA Rameter Answer lt Sig_Number gt integer 1121314 Sig Name string up to 8 ASCII characters No Samples integer 51211024 12048 1 4096 18192 No Of Bins CH1 integer 1to31 No Of Bins CH2 integer 1to31 Bin X CH1 integer Bin Min to Bin Max Bin X CH2 integer Bin Min to Bin Max Phase X CH1 j float T to T lt Phase_X_CH2 gt float T to 1 Example Boa Output Mtone Par gt B 1 Telefon 2048 3 2 25 85 256 11 102 0 000E 00 1 5 707E 00 3 14150E 00 1 234E 00 0 14170E 00 NEUTRIK CORTEX INSTRUMENTS V 3 32 53 71 RTM Multitone Audio Test System User Manual OUTPut 1 2 MTONe CRESt Use Queries the Crest factor of the active multitone signal Answer lt Crestfac gt float Range any
13. D C 48kHz f BkHz Advanced Dutput source ISDN w Input source Analog v Advanced i Level V File Graphic 0 1 1 1 20 200 2000 20000 Frequency Cursorat 20000 Hz 401 d n Chi ei Fig 25 RT EVAL Screenshot Fig 25 shows a typical screen shot of the RT EVAL software with generator analyzer multitone system configuration amp measurement panel Please contact you local representative to get a free copy of this package Units amp Conversion Especially in the field of telecommunication there exists a large number of different units to express a level value while for practical reasons amp 7 7 provides a restricted number of these units only The subsequent table lists the most common units and provides the necessary conversion formulas and examples for a better understanding NEUTRIK CORTEX INSTRUMENTS V 3 32 67 71 RTM Multitone Audio Test System User Manual Unit Explanation Conversion Formula Examples dB Decibel unit of measure of relative voltage V level dB 20 log V dBV RMS Voltage in dB referred to 1 Vans ABV 20 108 Yun OdBV 20 log dE ss L Le Viis aBV Peak Voltage in dB referred to 1 V V I V p y SES dBVp 20 log ee Se d OdBVp 20 Logo d Peak Peak dBm Power in relative to 1 mW Please notice that Vous I Visa every dBm result refers to the act
14. RT 1M into the normal operation after it has been in the armed mode In the normal mode the Trigger LED will be dark INPut TRIGger CONFiguration LOOSE TIGHT USER Use Sets the trigger configuration Range LOOSE TIGHT i USER string LOOSE Applies the normal trigger condition on an incoming multitone burst This configuration is especially suited for industrial applications where both multitone generator and analyzer are located in the same housing TIGHT Applies the tight trigger condition on an incoming multitone burst This configuration should be used for broadcast applications where the signal is inserted into a shortly interrupted broadcast signal USER This configuration allows the user to define the trigger condition individually However since this requires a highly sophisticated fine tuning it is strongly recommended to be used by very advanced users only Default LOOSE Query Use command INPut 1 2 STA Tus Example B gt Inp Trigger Configuration Tight Explanation It is recommended to change the trigger configuration for broadcast operation only and to select the TIGHT condition in such cases As soon as RT 1M is used again for industrial applications the trigger configuration should be re set to LOOSE INPut TRIGger USRConfiguration lt setbin1 dB gt lt setbin2 dB gt lt emptybin dB gt Use Allows to custom design the trigger configuration by defining the trigger bins Parameter lt setbin 1
15. SELectiverss UNIT IODVIWVIL 56 MEASurement 1 2 SELectiverss lt binstart gt binstop 57 MEASurement 1 2 NOISe UNIT JIOBVINT 57 MEASurement 1 2 NOISe ek 57 MEASurement 1 2 CROSstalk UNIT dB192 esee 58 MEASurement 1 2 CROSstalk AAA 58 MEASurement PHASe UNIT radideg sseessneeneeeseserneeesseeenrrssserrnnrrnneerrrernnn 58 MEASurement PHASe SCALe Scale ek 58 MEASurement 1 2 PHASe sopa ai deta 59 MEASurement1 D TMESTART EEN 59 MEASurement1 DTMF cos cian nate due nme deeds 59 Device SIS rutas tias 60 EE 60 KE 60 O EE E o OE STATE EE 60 OO 61 dz M 61 do A p Eeer EE ee 61 a E E 61 kcal T taupe 62 TES deudas 62 pu ads 62 Ded ta up MA Ca E nM Ee 63 ID NE eo codd ead tes ux s bed ovata itte ata ah ava te C MUR es 63 WoW T rr TP PM ET tal eee Ps 63 NEUTRIK CORTEX INSTRUMENTS V 3 32 7 71 RTM Multitone Audio Test System User Manual TS A ae 63 kl EN 64 Examples sy iee bet aayind a lt 64 Use or an OPC command Geseit ern irr eer a eoe ven e cod e peces 64 Use of MAV bit in the status Byte register ooooococccccnnnnnocccccccnonennnnnanannnos 64 EEE Standard Status Data Structure gege erba e n reo Loc P RI eg Dota g ouccto 65 S APPLICATION HINTS ci ena Ma aa cS esso ESOS 66 Arbitra y Generator cipal aire sii 66 Alignment and Adjustments for Audio Repair Facilities 66 Ge
16. UNIT rad deg Use Range Default Example Defines the unit in which the phase measurement result shall be expressed rad i deg string rad a MEAS PHASE UNIT DEG MEASurement PHASe SCALe lt Scale gt Use Defines the lower border of the phase plot scale in which the result shall be expressed The scale always comprises a full circle i e 2x rad or 360 deg respectively Parameter Scale float Range 27 to 0 i 360 to 0 Default 0 NEUTRIK CORTEX INSTRUMENTS 58 71 V 3 32 RTM Multitone Audio Test System User Manual il v Example E MEAS PHASE SCALE 180 180 to 180 deg D vv Meas Phas Scal 0 0 to 27 rad MEASurement 1 2 PHASe Use Returns the measured phase difference between the 2 channels of the last received multitone signal The phase value can be calculated only if both channels have recognized a trigger and if at least one signal bin is identical i e set on both channels ATTENTION In order to get accurate phase values it is important to set the input ranges of both channels to the same level Answer SigBin 1j integer Phase 1 float string SigBin_n integer Phase_n float string Range SigBin_n Bin_Min to Bin_Max see Equation 4 and Equation 5 Phase_n float NaN string Unit as defined by command MEA Surement PHASe UNIT Example B gt MEAS1 PHASE 2H 3 1 24E0 deg 23 9 27E 1 de
17. amp 4 represent the empty bins Frequency Fig 24 Trigger Definition NEUTRIK CORTEX INSTRUMENTS 36 71 V 3 32 RTM Multitone Audio Test System User Manual Obviously the levels of the five signal bins together with their frequencies make the uniqueness of the 7 trigger signal The application of the User trigger allows to individually define the headroom between the OdB line and the bottom bars T However this is a very delicate operation and therefore not recommended for new users of X7 Anyway in case that this feature truly has to be used please refer to the explanations of the commands INPut TRIGger CONFiguration and INPut TRIGger USRConfiguration as well as to the helpfile of the RT EVAL software package Remains the question about the reference level of the analyzer since especially for long distance transmission lines this instrument cannot use the same reference voltage potential as the generator The solution is to assume the currently set input range of the analyzing 7 unit as reference level This level equals the max detectable amplitude of all incoming signals all higher levels would be clipped and is represented by the OdB line on top of Fig 24 Consequently all received signals will be analyzed against OdB Applied on the trigger detection criteria this means that the level pattern of an incoming multitone trigger must be within a certain range defined by the trigger configura
18. f max Af lt 20kHz may be displayed Equation 5 Maximum Signal Bin Frequency Besides the above equations there are no other constraints for the definition of a multitone signal This means you can use any bin representing a frequency below or equal to 20kHz as a signal bin It is up to the operator what the intention of the signal bins is Please refer also to chapter Signal Table Phase Crest Factor Optimization In order to achieve a low Crest factor RT EVAL an evaluation PC program provided free of charge by NEUTRIK offers a special feature that allows to optimize the phases of any multitone signal The results can be loaded directly from or back into the Zi 24 Generator Low Crest factors are important for two reasons First the peak level of the multitone signal raises the necessary input range for the analysis and thereby reduces sensitivity for the low level signal components Second the low energy content of a multitone signal with high Crest factor may barely stimulate the DUT A non optimized multitone signal may show Crest factors of up to 10 20dB while with a proper minimization algorithm Crest factors as low as 2 6dB can be found This difference of 14dB can directly enhance or decrease the dynamic range of the analyzing system NEUTRIK CORTEX INSTRUMENTS V 3 32 19 71 RTM Mul
19. for start multitone signal in generator No parameter in list referring to received data in analyzer Output 1 amp 2 muted while multitone is started No trigger detected No stereo trigger detected e g for phase measurement Measurement function needs 21 identical bins on both channels Measurement function needs 21 different bins on both channels Analyzer overload Battery low memory backup Hardware and software revisions do not match Minimum one external measurement required beforehand Measurement not possible Signal bins defined too close to each other chose higher block length or change signal bins DTMF receive buffer overflow RS232 GPIB Interface Output Buffer overflow RS232 GPIB Interface Input Buffer overflow 600 716 Please report to NEUTRIK Example gt System Errors 130 203 204 E JM SYST ERR 0 Explanation If no errors occurred a 0 is returned In any other case the list of error numbers in the queue is returned All errors are cleared in the instrument after the query SYSTem INFormation Use Query for serial number hardware revision and firmware version of RT 1M system Compatible with SCPI lt IDN gt command Answer lt Manufacturer gt string lt Instrument_type gt string lt Serial_number gt string 4 digits Firmware Revision float Example as System Information E NEUTRIK RT1M 0456 3 20 V 3 32 NEUTRIK COR
20. gt integer lt setbin 2 gt integer lt emptybin gt integer Range lt setbin 1 gt 10 to 50 dB lt setbin 2 gt 10 to 50 dB lt emptybin gt 0 to 80 dB Query Use command INPut TRIGger USRConfiguration Example Blo Inp Trigger Usrconfiguration 20 40 80 NEUTRIK CORTEX INSTRUMENTS V 3 32 47 71 RTM Multitone Audio Test System User Manual Explanation This command requires highly sophisticated handling for proper operation BEE It shall not be applied as by very advanced users only INPut TRIGger USRConfiguration Use Queries the defined trigger configuration Answer setbinl integer lt setbin2 gt integer lt emptybin gt integer Range lt setbin1 gt 10 to 50 dB lt setbin2 gt 10 to 50 dB lt emptybin gt 0 to 80 dB Example B gt Inp Trigger Usrconfiguration gt E 20 40 80 Explanation See chapter Broadcast Mode INPut 1 2 STATus Use Queries the complete input channel status Answer lt Range_Unit gt float amp string RANGE 60 to 20 dBVp 0 001 to 10 Vp lt SW_Filter gt boolean SWFILTER OFF i CWEighting i CCIT lt Front_Conn gt boolean FRONT OFF ON lt Link gt boolean LINK OFF ON SYNC Mode boolean SYNC INT i INTN EXT EXTN lt Deemphasis gt boolean DEEMPHASIS OFF ON lt Trig_Config gt string TRIGGER LOOSE TIGHT USER Example Es Inp2 Status 5H RANGE 3 5000E0 dBVp SWFILTER CCITT FRONT OFF
21. lt Length gt Use Parameter Range Unit Default Query Example Explanation Definition of the pretrigger duration for the active multitone signal in milliseconds lt Length gt float 0 to 30000 ms milliseconds 0 Not possible D vv O G tput Mtone Pret 0 Outp Mtone Pretriggerlength 50 5 The duration value is rounded to the next possible value The duration of the pretrigger excludes the duration of the trigger which always occupies some 42ms The value 0 defines the shortest possible pretrigger length of Oms The command mainly allows the DUT to stabilize before the multitone signal is transmitted OUTPut MTONe MTONelength lt Length gt Use Definition of the multitone signal duration for the active multitone signal in milliseconds Parameter lt Length gt float Range 0 to 30000 Unit ms milliseconds Default 0 Query Not possible Example BO Output Mtone Mton 500 Explanation The duration value is rounded to the next possible integer multiple of the duration of one multitone block The value 0 results in transmission of the min number of multitone blocks The command mainly allows the DUT to stabilize onto the multitone signal before analysis is started NEUTRIK CORTEX INSTRUMENTS 50 71 V 3 32 RTM Multitone Audio Test System User Manual OUTPut 1 2 BINlevel Level lt Unit gt Use Parameter Unit Range Query Example Explanatio
22. of the azimuth angle of the playback head of a tape recorder a procedure that normally has to be repetitively performed for low mid and high frequencies Cellular Phone Testing Increasing production volume based on the fast growth of cellular networks and coupled with the requirement for 10096 testing of the units makes an improvement at production bottleneck the audio analysis necessary 47 is ideally suited to serve as a high speed audio analyzer for production testing The LF output signal of the system may be RF modulated and transmitted through an antenna to quickly obtain the frequency response and distortion in the voice band of the whole signal path Frequency shifts as they may appear on AM FM transmissions are eliminated by the synchronization capabilities of 27 14 SINAD measurements with a single bin stimulus are possible down to a value of 1dB The trigger detection works reliably if the signal is transmitted on the second channel too The dual channel capabilities of 27 74 even makes it possible to perform transmit and receive testing simultaneously One channel generates the source signal for the transmitter path of the phone Mic input while an external test demodulator feeds back the signal to the analyzer of the same channel The output of the second channel is fed into an external modulator that supplies the RF signal for the receiver path of the phone The phone demodulates the signal and the feeds into the s
23. positive number gt y 2 Example OUTP1 MTONe CREST gt 2 33433E0 Explanation Refer to chapter Phase Crest Factor Optimization for further explanations NEUTRIK CORTEX INSTRUMENTS 54 71 Vou RTM Multitone Audio Test System User Manual MEASurement Subsystem MEASurement 1 2 LEVel UNIT ABVp Vp dBV V Use Defines the unit in which the level results shall be expressed Range dBVpi Vp dBViV string Default dBVp Example Fi MEAS1 LEV UNIT VP MEASurement 1 2 LEVel Use Returns the measured signal bin levels of the last received multitone signal for one channel Answer Set bin n integer Amplitude n float amp string level value amp unit Range Set Bin n Bin Min to Bin Max see Equation 4 and Equation 5 Amplitude n float NaN amp string Unit Defined by MEASurement 1 2 LEVel UNIT dBVp Vpid BV VV Default NaN not a number Example Boa MEAS1 LEV 2H 3 1 240E0 dBV 23 9 727E 1 dBV 84 8 254E 1 dBV Explanation The returned level vector is grouped in result pairs starting with the first signal bin number a the corresponding level value a white space and the unit in which the result is expressed Pairs are separated by commas If a received level is too low to be measured NaN not a number is returned MEASurement 1 2 DISTortion UNIT dB V V Use Defines the unit in which the distortion result shall be
24. request SRQ The programmer can select reasons to issue a service request by altering the contents of the service request enable register See also chapter IEEE Standard Status Data Structure Enable value Byte 0 to 255 SRI GI 32 enables standard event status bit ESB SRE Use The Service Request Enable query allows to determine the current contents of the service NEUTRIK CORTEX INSTRUMENTS V332 61 71 RTM Parameter Range Example Multitone Audio Test System User Manual request enable register See also chapter IEEE Standard Status Data Structure lt Enable_value gt Byte 0 to 255 aS SRE E 32 ESR Use Calculation Parameter Range Example PSC Use Parameter Range Default Example The standard Event Status Register query allows the programmer to determine the current contents of the standard event status register Reading the standard event status register clears it See also chapter IEEE Standard Status Data Structure ESR n 128 ng 64 n5 32 nj 16 n3 8 n 4 n 2 no n7 Power On event flag indicating that an Off to On power transition has occurred Not used De Command error event flag indicating that either a syntax or a semantic error has Ns been detected The error number can be read with the lt system errors gt query Not used ny Device specific error event flag e g no trigger detected The occurred
25. status summary bit ESB indicating whether any of the enabled events has occurred since the last reading of the standard event status register n4 Message available summary bit MAV The MAV message indicates whether or not the output queue is empty Whenever RT 1M is ready to accept a request by the controller to output data MAV summary message will be TRUE n3 Not used n Not used n Not used No Not used Example B gt STB 2H 32 OPC Use The OPeration Complete command causes RT 1M to generate the operation complete message in the standard event status register Bit 0 when all pending selected device operations have been finished The OPC command allows synchronization between controller and RT 1M il gt esr clears previous events ese 1 sre 32 enable operation complete event output mtone start OPC RT 1M will request service serial poll as soon as the measurement is finished Example OPC Use The OPeration Complete query causes RT 1M to place an 1 into the RT 1M output queue when all pending selected device operations have been finished The OPC command allows synchronization between controller and RT 1M using the MAV bit in the status byte register See also chapter IEEE Standard Status Data Structure Parameter lt OPCvalue gt boolean Range 0 not finished 1 finished Example B gt OPC E 1 Explanation Use OPC with serial polling e g M
26. 3 No TRIGger command found e g ARMed 140 No MEASurement command found e g LEVEL 141 No MEASurement 1 2 command found e g TDN 145 No device status command found e g OPC 149 TRIGger configuration parameter expected e g LOOSE 150 No parameter expected 151 Float parameter expected 152 Float parameter out of range e g INP RANG 5E3 153 Integer parameter expected 154 Integer parameter out of range 155 String parameter expected e g ON 156 ON or OFF string expected 157 Filter parameter expected e g CCITT 158 Location parameter expected e g FRONT 159 Sync parameter expected e g EXTERNAL 160 String too long 161 Wrong number of samples 512 1024 2048 4096 8192 162 Corresponding frequency to bin number out of range 163 Phase value out of range 164 Wrong number of MT Parameter 165 IEEE bus error 166 Output buffer overflow 167 Bins must be in increasing order 168 Too many parameter 42 71 NEUTRIK CORTEX INSTRUMENTS V 3 32 RTM 169 170 180 182 190 191 199 200 201 202 203 204 205 206 210 220 230 240 246 250 255 256 Multitone Audio Test System User Manual Integer parameter must be in increasing order Illegal unit Option not installed e g FLOAT Command not executable during input trigger armed mode Not available in this hardware version Not available with this firmware version Unexpected error occurred please report to NEUTRIK No parameter in list
27. 4 just use the query command MEASurement 1 2 MTSinad to get the calculated value In practice the MT SINAD result may differ slightly from a conventionally measured SINAD value due to intermodulation products between the signal bins However in qualitative terms the results are equal as proven in numerous setups RSS Selective Measurement The MEASurement 1 2 SELectiverss lt binstart gt lt binstop gt command allows to query the TD N result of a user defined band anywhere between 20Hz and 20kHz Both the lower and the upper border of this band may be set freely to any bin number they don t have to be identical to the signal bins of the transmitted multitone signal Amplitude Bin win Bin max d Signal E Signal Bin 3 Bin 2 Signal Bin 1 20 PA P 20k Frequency Hz Bin Start Bin Stop Fig 21 RSS Selective Plot NOTE Be aware that if a signal bin is within the band of interest the RSS selective result will represent the signal bin level distortion noise The RSS selective feature is especially helpful if a certain component of a received signal shall be investigated For instance after transmission of a single tone signal it allows to evaluate the individual harmonics of the fundamental frequency Noise As for distortion analysis the noise measurement divides the frequency band in subbands split by the signal bins and calculates the noise values of these subbands NEU
28. AV NEUTRIK CORTEX INSTRUMENTS 60 71 V 3 32 RTM CLS Use Example Explanation ESE Use Parameter Range Example Multitone Audio Test System User Manual The CLear Status command clears status data structures i e standard event status registers so that the corresponding summary ESB bit is clear See also chapter IEEE Standard Status Data Structure e CLS CLS has same effect as ESR query except it is a command The standard Event Status Enable command sets the standard event status enable register bits The standard event status enable register allows one or more events in the standard event status register to be reflected in the ESB summary message bit See also chapter IEEE Standard Status Data Structure Enable value Byte 0 to 255 As ESE 32 enables command error event ESE Use Parameter Range Example The standard Event Status Enable query allows the programmer to determine the current contents of the standard event status enable register See also chapter IEEE Standard Status Data Structure Enable value Byte 0 to 255 ESE gt H 32 SRE Use Parameter Range Example The Service Request Enable command sets the service request enable register bits The service request enabling allows a programmer to select which summary messages in the status Byte register may cause service
29. Audio Test System User Manual Explanation The returned noise vector starts with Bin Min i e the first possible bin 220 Hz followed by the noise result between this bin and the first signal bin Second pair is the bin number of the first signal bin and the noise value between this first signal bin and the second signal bin etc Last pair is the last signal bin with the noise result between the last signal bin and Bin_Max i e the last possible bin lt 20kHz See also Fig 22 If a band between two signal bins is too narrow to measure noise value NaN is returned MEASurement 1 2 CROSstalk UNIT dB Use Range Default Example Defines the unit in which the crosstalk measurement shall be expressed dB i 96 string I ES EAS1 CROS UNIT dB MEASurement 1 2 CROSstalk Use Default Example Explanation Returns the measured crosstalk of the last received multitone signal for one channel The crosstalk result can be evaluated only if at least one signal bin of each channel is set at an exclusive frequency NaN not a number Ela MEAS1 CROS 2H 3 87 dB 11 67 dB The returned result pairs indicate the signal bin number followed by a the corresponding crosstalk value a white space the unit in which the result is expressed and a H If the crosstalk value is too small to be measured NaN not a number will be returned MEASurement PHASe
30. EEE 488 interface HT BASIC Program Example 10 20 30 Adr 11 40 50 Adr Adr 700 51 GOSUB 900 60 OUTPUT Adr Output Mtone Active 1 END 65 OUTPUT Adr Output MTone Start END 70 OUTPUT Adr Measurement1 Level END 80 GOSUB 1000 90 PRINT 100 GOTO 65 110 STOP 900 905 DIM Inf 100 910 OUTPUT Adr System Information END 920 ENTER Adr Inf 930 PRINT Inf 940 RETURN 1000 1010 DIM Fcv 1000 1020 DIM X 10 1030 DIM Y 20 1040 1050 ENTER Adr Rcv 1060 Xpos POS Rcv 1070 Ypos POS Rcv 1080 1090 WHILE Xpos gt 0 AND Ypos gt 0 1100 XS Rcv 1 Xpos 1 1110 X VAL X 1120 Ypos POS Rcv 1130 IF Ypos gt 0 THEN 1140 YS Rcv Xpos 1 Ypos 1 1150 ELSE 1160 YS Rcv Xpos 1 LEN Rcv 1170 END IF 1180 Y VAL YS 1190 RcvS Rcv Ypos 1 LEN Rcv 1200 Xpos POS Rcv 1210 PRINT Binf X Meas Y 1220 END WHILE 1230 RETURN 1240 END RI 1M Demo Program enter IEEE address here evaluate output enter address J read device informations measurement loop terminate output with END read the measurements read system information interpret incoming data stream read data A find X Y separator find Y X separator as long as there are separators do isolate X value convert X string to value A find Y X separator is there anoth
31. RSS value from Bin 11 to Bin 32 E 32 1 01352169 02 dBV including levels of Bin 11 32 The RSS selective measurement see p 3 30 allows to measure the total distortion noise in any frequency band between 20Hz 20kHz lt binstart gt defines the lower border of this band while lt binstop gt defines the upper border of the band Please notice that if the selected band comprises a signal bin the RSS selective result will include this signal bin level in addition to the distortion noise value of the band MEASurement 1 2 NOISe UNIT dBV V Use Range Default Example Defines the unit in which the noise measurement results shall be expressed dBV V string DBV Fe 3 MEAS1 NOISE UNIT V MEASurement 1 2 NOISe Use Returns the noise values of all the bands between 20Hz gt Bin Min Bin Min SigBin 1 etc SigBin n gt Bin Max Bin Max gt 20kHz see also chapter Noise Answer Bin Min Integer Noise 1 float string SigBin_n integer Noise_n float string Range Bin_Min Bin_Min Set_Bin_n Bin_Min to Bin_Max see Equation 4 and Equation 5 Noise_1 Noise_n float NaN string Unit As defined by command MEASurement 1 2 NOISe UNIT dBV V Default NaN not a number Example Bs Measurement1 Noise 5H 3 6 56E 3 V 11 7 32E 3 V 27 6 55E 3 V 87 5 87E 3 V 2048 4 27E 3 V NEUTRIK CORTEX INSTRUMENTS V 3 32 57 71 RTM Multitone
32. TEX INSTRUMENTS 43 71 RTM Multitone Audio Test System User Manual INPut Subsystem INPut FRONt ON OFF Use Range Default Query Example Activates either front or rear panel input connectors output connectors are always active at front amp rear panel OFF i ON boolean ON front input connectors are active Use command INPut 1 2 STATus f gt Inp Fron OFF INPut 1 2 LINK OFF ON Use Range Default Query Example Links internally the generator output of RT 1M to the analyzer input The input connectors of the selected channel are physically disconnected at front and rear OFF i ON boolean OFF Use command INPut 1 2 STATus il BO Input2 Link ON Fi 3 INP1 LINK OFF Explanation This command allows e g to check the proper operation of RT 1M INPut 1 2 RANGe lt Range gt Unit Use Parameter Unit Range Default Query Example Defines the input range amp unit for an input channel lt Range gt float lt Unit gt string dBVp Vp 60 to 20 dBVp rounded to nearest 0 1dBV 0 001 to 10 Vp 0 dBVp Use command INPut 1 2 STA Tus il EH INPUT1 Range 0 dBVp EB Inp2 Rang 0 5 Vp Explanation Insert a white space between the value and the unit The allowed units are peak level units only since the Crest factor of the input signal is unknown 44 71 NEUTRIK CORTEX INSTR
33. TRIK CORTEX INSTRUMENTS V 3 32 31 71 RTM Multitone Audio Test System User Manual Amplitude dB Bin min Band 1 Band 2 Band 3 Band n Band n 1 Max T BN A EA A A s Y mE Se n i Signal 3 Signal 2 Bin c Bin b Signal n Bin x Frequency Hz 2b a b 1 20k Fig 22 Noise Plot Consequently a multitone measurement with n signal bins results in n 7 noise values each calculated internally by amp 7 according to the following formula Noise 27 Y Us RSS value of all odd bins in a band Equation 13 Noise Calculation NOTE Equation 13 describes the internal noise calculation of 27 11 i e the actually returned noise results must not be re calculated in any way Full Band Noise MeasurementTo evaluate the noise value in the full frequency band 20Hz 20kHz following equation has to be applied N agang JNV N V N V Equation 14 Full Band Noise wherein NN are the returned noise results expressed in V of any multitone measurement NEUTRIK CORTEX INSTRUMENTS 32 71 V 3 32 RTM Multitone Audio Test System User Manual Crosstalk The Crosstalk Plot may be calculated only if a stereo signal is transmitted This stereo signal must have separate bins set in the 2 channels in a way that the respective bins remain unused in each other channel In case of bad channel separation of the DUT the unique frequencies of channel A talk into channel B
34. UMENTS V 3 32 RTM Multitone Audio Test System User Manual INPut SYNC INTernal INTNoheader EXTernal EX TNoheader Use Range Default Query Example Explanation Defines the synchronization mode of the instrument INT INTN EXT EXTN boolean INT INTN EXT EXTN INT Analyzer sampling clock is derived from the generator crystal No frequency shift correction is performed Use this mode if analyzer and generator are located together and no frequency shifts are expected Max allowable time delay is Is Analyzer sampling clock is derived from the generator crystal No frequency shift during transmission must occur The multitone signal is sent out without any header The analyzer expects the multitone signal without trigger and SYNC block Use this mode if analyzer and generator are located together but no header information can be transmitted e g muted measurements or for analysis of externally generated signals Max allowable time delay is 50ms The analyzer clock is synchronized to the frequency of the SYNC block in the header of the received multitone burst Frequency shifts are compensated This mode is recommended if notable frequency shifts are expected Max allowable time delay is 1s No synchronization is transmitted or performed at all Analyzer clock runs at the frequency synchronized to the last transmitted multitone burst in Sync Mode EXT No further tuning will be performed Analyzer expects th
35. USRConfiguration USRConfiguration PARameter ACTive PRETriggerlength MTONelength STARt CONTinuous PARameter NAME BLOCklength CRESt MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement MEASurement STB OPC OPC CLS ESE ESE SRE SRE ESR PSC PSC IDN RST TST WAI Following terms are used in the command description LEVel DISTortion DISTortion MTSinad SELectiverss SELectiverss NOISe NOISe PHASe PHASe PHASe CROSstalk CROSstalk DTMF DTMF User Manual UNIT UNIT UNIT UNIT SCALe UNIT STARt Symbol Description Used to enclose one or more optional Parameter to control RT 1M Omitting the default Parameter causes the system to use the default action Used to enclose one or more Parameter that may be included several times Indicates a query by appending the question mark to the last keyword in a command Not all commands have a query some are only query commands Read this signal as an OH It is used to separate alternative Parameter lt gt Used to enclose an SCPI defined parameter Used to separate elements of a RT 1M command Used to separate commands in a command list Used to separate argument
36. ast one talk and listen address unless totally transparent or a talk or listen only device The address of the 7 7 can be adjusted with the DIP switch at the rear panel of the instrument see Fig 2 Each switch position has a number printed underneath The resulting IEEE address is the sum of all numbers where the switch is in position 1 The above illustrated example has an address selection of 3 since switch 1 and switch 2 are in position 1 The five switches allow the selection of any address in the range from 1 to 31 inclusively Audio Connection T features balanced and unbalanced BNC and 4mm banana connectors for both inputs and outputs Balanced connections enhance the noise and hum immunity and are always recommended for measurement purposes X7 1 can also handle unbalanced signals Unbalanced signals normally have one hot signal 7 e DELE against chassis ground For this reason unbalanced El High Hight d O O O connections are recommended for short connections CH 1 CH2 only less than 1m 3 feet or in a relatively noise free 7 environment Qo o 0 0 You may use either the set of front connectors with two inputs amp outputs or the equivalent set of connectors at Fig 3 Front Connectors the rear panel of the instrument Input Caution Do not connect both front and rear panel connectors at the same time since this may result in signal mismatching NEUTRIK CORTEX INSTRUMENTS 12 71 V 3
37. at all may be activated with command INPut SYNC INTernalllNTNoheaderiEXTernaliEXTNoheader offering the four following modes INTernal The analyzer is linked to the generator clock of the same unit and the multitone signal is preceded by a header trigger amp SYNC block This mode may be chosen if the multitone burst is generated in the same unit where it is analyzed and if no major frequency shifts occur in the DUT The burst is initiated with command OUTPut MTONe STARt and transmission must not show a delay of more than 1s INTNoheader Again the analyzer is linked to the generator clock of the same unit but no header is transmitted The benefit of this mode appear in noisy environments where the trigger cannot be detected and for analysis of signals being generated by the DUT itself However the max allowable transmission duration is 50ms i e the multitone burst must arrive at the analyzer at latest after this time from the moment of its initiation NEUTRIK CORTEX INSTRUMENTS 26 71 V 3 32 RTM Multitone Audio Test System User Manual EXTernal In case of expected clock frequency differences between the generator and analyzer the user has to activate the EXT mode Frequency shifts appear e g in combination with analog tape recorders where the recording and the playback speed are not identical or due to local separation of generator and analyzer Up to 1s transmission time is allowed EXTNoheader This mode ma
38. connection through the ground wire of the power cord This connection is essential for safe operation Never operate the instrument if safety ground is unavailable or has been compromised NEUTRIK CORTEX INSTRUMENTS V 3 32 11 71 RT 1M Multitone Audio Test System User Manual Mains Cable The enclosed mains power cable has an unconnected end with three colored leads which correspond to Brown Live AC Blue Ground Yellow Green Earth Attach a mains plug to the cable that fits the receptacles of your country IEEE Connection The 7 7 system provides an IEEE 488 interface standard design interface for programmable instrumentation which is connected to the IEEE bus using a standard IEEE 488 interface cable from the rear panel illustrated in Fig 2 IEEE Address RS 232 Interface With the IEEE interface bus up to 31 instruments can 1 be interconnected The cables have identical piggy inii O E GR back connectors on each end so that several cables xg can be connected in virtually any configuration There IEEE 488 Interface must be of course a path from the computer to every device operating on the bus As a practical matter avoid stacking of more than three or four cables to a single connector If the stack gets too long any force on the stack can damage the connector mounting Be sure that each connector is Fig 2 IEEE Connector firmly screwed in place IEEE Address Selection Each IEEE device has at le
39. d tri 16 O meme em rm mrn n reh e rennen rre rn rennen 17 Sampling Rate Gace rr C TS 17 Gilet e LBE 18 Frequency Spacing tox nutrias da a iaa 18 TE EE 19 Phase Crest Factor Optimization vacio lts 19 Comparability of Multitone Measurements c oooooooooooooccccnnnnnonnnnncnnnnnnnonononananananananans 20 leie 20 211010 s1510 LE 1I Sl S 20 Blocklengi 1024 o c ai aia 21 Blocklengili 2048 ico rd EAE PAR RE RR RR eua B 21 BIOCKISn t4 09D oa iet roo etd vod i HORUM even eter cedit eer Ae aan Bett qa doped ts 21 silere dati BEE 21 A EQ IN QUADRO RAD TRAD ERROR e 22 BOCK DIAG Tun Acc tni EEE i ua em ID Mt M 22 RTR DE 22 Anal g SEC TON caia m 22 EEN 23 BlOGK Did Lu WEE 23 NEUTRIK CORTEX INSTRUMENTS V 3 32 5 71 RTM Multitone Audio Test System User Manual Analog SSCHON io D 23 EIKGFIFIU Scio tra acorde ege ca Re pipi Queis runc pad gege 23 Digital SECON m E LT 24 Definition of Multitone Sinai decuit dod RR RE ao ea 24 A MU EID EM EI tT E 25 genee EE 26 prices eR eo del 26 Ee 26 Synchronization lege ac tte ere e eer ene e ri en pale ne Rae ve Rn une Ran 26 UNE as c rs utt e Seth dee oe ee Me 26 IN TNOhead6r 2 eoo ote eret eo eee itte re EE eoe e tete ene Pen Desin 27 E EE EE 27 EX da 27 SE O O 27 Signal Analysis amp Result Queries EEN 28 CA ELE Eet 28 DISTOMUO eet te ia tdi 28 RMS andi RSS Valle teca 29 Interpretation of RTE 29 DISTOFION P a a he e Eee enn 29 Full Band TD N Measurement ss
40. e Tools coit cie oce 10 Speaker Testing 66 Specifications EEN 69 o e b anti eter tutt es 26 Synchronization Frequency REENEN 26 Mode eee ee eet suus 26 System Description 16 T TD N Full Band Measurement 30 TDEN Val 22 22 0 m ota doe pane 28 Test of Function ssuuuse 15 THD N Calculation 30 TIGHT UGGS AA 36 TM uii acte ete red 25 26 Configuration sess 36 LED Indeator sseeeeeeeeneeeeneeesennr rennene 14 U Unbalanced Signals 12 iiM HORE 67 Unpacking CE 11 USER Trigger etate coat 36 V Voltage selector 11 W WARRANTY en nnnnnnnnnnn nnn nnn nnns nenas 3 X POT AL dm 33 NEUTRIK CORTEX INSTRUMENTS V 3 32 71 71
41. e signal with no trigger information and generator is set to transmit the multitone signal only No major time delay must occur in that mode This mode requires at least one measurement in EXT mode before to ensure that the analyzer crystal is tuned Use command INPut 1 2 STATus gt D Inp Sync Internal INPUT SYNC INTN Any multitone burst transmission amp sampling must be initiated by OUTPut MTONe STARt INPut SWFilter OFF CWE CCITT Use Activates one of the implemented software weighting filters Filters are selected for both channels simultaneously The filters may be engaged also after the measurements has been performed This allows to get first unweighted and afterwards weighted results Range OFF CWE CCITT boolean Default OFF Query Use command INPut 1 2 STA Tus Example Boa INPUT SWFILTER OFF a gt Inp SWF CWE NEUTRIK CORTEX INSTRUMENTS V 3 32 45 71 RTM Multitone Audio Test System User Manual INPut DEEMphasis OFF ON Use Range Default Query Example Activates the 750us deemphasis which applies on both channels regardless of other filters OFF ON boolean OFF Use command INPut 1 2 STATus gt INP DEEM ON D B gt Input Deemphasis OFF INPut TRIGger ARMed Use Query Example Explanation Puts RT 1M into the armed mode where the analyzer waits for an exte
42. econd analyzer channel of 7 ff Rub amp Buzz Speaker Testing The multitone feature of 7 7 is ideally suited for Rub A Buzz speaker testing in production lines Most frequently seen defects of speakers are mechanical friction of the moving coil and the magnet as well as excentrical alignments leading to a staggering movement of the coil In any of these cases the speaker either starts to produce nonlinear distortion or adds additional signal energy to frequencies not being part of the original signal Both of these effects can be measured in a fraction of a second Harmonics and new frequencies will appear in the distortion and in most cases in the noise plot Anyway the stimulation of a speaker with a multitone signal is more realistic and comes closer to real world signals Actually the mentioned effects may remain unnoticed when stimulating with a single frequency only NEUTRIK CORTEX INSTRUMENTS 66 71 V 3 32 RTM Multitone Audio Test System User Manual RT EVAL Software Package In order to simplify the operation of 7 14 especially for new users an easy to understand evaluation package has been released This versatile tool provides not only access to almost all available features of the unit but also extends this range by some very useful functions like a Crest factor optimizer etc NEUTRIK RT Eval for Windows 95 1 60 olki File Panels Measurement Help SME S otme es wi El wl 2 x 4 System mode Dm dBFsp
43. ed by using Equation 1 With these two values the signal bin level may be calculated according to I Uou pus Ubin with n total number of signal bins RMSF n Equation 6 Bin Amplitude Following example shall illustrate the signal definition procedure The multitone signal shall have three signal bins at 300Hz 1kHz and 3kHz Both channels are identical The name of the signal is Telefon Since the three frequencies are fairly wide apart we may use a blocklength of 512 resulting in a frequency spacing of 93 75Hz To calculate the signal bin numbers refer to Equation 7 fo _ 300Hz _ Binn Round Tu 93 75 Hz Equation 7 Bin Number Consequently the bins equaling 300Hz 1KHz and 3KHz have the numbers 3 11 and 32 The definition of the phases can be done manually or by using the Crest factor optimizer of RT EVAL Finally the table may look as follows l Telefon 512 93 327 2 11 32 23 l11 32 3 0141 1 234 0 707 0 0 010 0 tll The duration of this multitone signal not considering the header explained below is the reciprocal value of 93 75Hz which is 10 67ms ATTENTION Do never define exclusively the three signal bins 562 5Hz 1406 25Hz and 3 0kHz as multitone signal since these three frequencies form the trigger of a multitone burst header Header Each multitone burst is preceded by a header comprising trigger and clock synchronization The standard trigger signal has a Trigger Clock sync
44. ee emere nennen renean 30 TEIDN Galculatiorn 2 ret e tee e mee 30 MISINAD iere rai e neve o ER 30 RSS Selective Meaeurement nennen nnns 31 A ERR 32 SEU E lee Ten 32 e TEE 33 AA a OSA AA 34 EX ME DIO ER 34 BIG AD CAS MOG ehre ebe eebe vereor ere eee 35 Mode of ODDS estan este ten tata Gace nits B etudiant eoque 35 sr m FAR 35 Trigger GOA IQUITOS id 36 Application Hints Troubleshooting oococccnnccnonooooononooooonnnnnnnnnnnnnnnononononononnnnnnnos 37 4 PROGRAMMING ca id ot ec eke M oa ss 39 Comtiamd SI Blue a a cin d b Od ca ig iba bela c a ca t e d 39 IEEE 485 Bee le EE EE 39 IEEE 488 2 Command Sne E A A A E A a aaa eai 39 Command inn E 39 Descriptive Symbols E 40 CGommandNolatton nen nnne nnn ansa nane snae rena 41 Command Seba adio Ra d dr rn rura d eee 42 SYSTem SUDSY STOR cetus befinden bot dor bon ea edad Ead Gau gx C oU ge Cirio d 42 SYSTem RESOb ict A 42 eh d RER GC 42 SYSTem INFormalion ei did 43 INP t SUBS Y SHIM s eot eet rre tnt geed 44 INPUFPFRONTION OPA cionado 44 INP Ut T EINKIOEEION iu decia ee a 44 INPut 1 2 RANGe Range Ulm 44 INPut SYNC INTernal INTNoheader EXTernal EXTNoheader 45 INPUES Wer OFFIOWEIGGOCLTT Muscat al cori Pei 45 INFOEN erbei 46 NEUTRIK CORTEX INSTRUMENTS 6 71 V 3 32 RTM Multitone Audio Test System User Manual UNF I EIGOOI ABMGOG iiti cte ette dedito tolera 46 INPOETRIOOSPABMOQG pt
45. en tested and found to conform with the statutory protective requirements Instruments of this type thus meet all requirements to be given the CE mark NEUTRIK CORTEX INSTRUMENTS 4 71 V 3 32 RTM Multitone Audio Test System User Manual TABLE OF CONTENTS TOMES EE 9 CORUM UIC ATION ee e o ede e C Lab do od 9 Accessories amp Options ococoooccocccccccccccccnnnnnnnancncnnnnnnnnnnnnnnnnnnnnnnnncrnnnnnnnnnnncnnnnnnn 10 Sottware Tools s o EE M as 10 Application Tele 10 DTME Te 10 Microphones amp Phantom Power Supply cccccccncccnococccccnccconnncnancccnnnonnnnn ocn ccnnncnnnnnnnns 10 2 INSTA ge Sap det lean cn utd o binds iS cl e 11 ele e DEE 11 RACIMOS A dee dd ri ne fc ecu 11 AG e Ee et ee EE 11 Mains Cable me emere nnmmnne nen rne rs rris ese rsen rsen rna 12 E EE Er tate cna eaa ete eee aaa enean 12 IEEE Address Selection cccccceccceecceecceecceeeceeeceeecauecaeecaeeceeeeseesanesaeeseeeseeeseeens 12 Audio Connection te O 12 Balanced Connect eds 13 Unbalanced Copnnechon eerdre rei e ne ieie an EAE AA EAIA 13 E Ee l ine Te EE 13 LED Md AlO S sata ai ition des 14 POWER iem mac eet EE EE 14 Lea ge Cee perme sete ee mrt ater in etd EUN ns deso MEER 14 AU e cece PEE 14 R gen 14 OVerlgad cac es ee tas tek laa cl ed Loca duc cdo cas EE 14 ENO AS eus oM A iN do e tee E a a CE Ee 14 ME el Sae 15 HT BASIC Program Example s meet ooo en Eco La pix ron 15 3 OYXSTEM DESCPIPTION RE 16 M lliterie SIJgHalS 2 dee p
46. epeated by applying the command OUTPut MTONe MTONelength For instance several multitone blocks may be transmitted before the analysis starts in order to stabilize the DUT and to let transients disappear The analysis itself requires a minimum of two blocks Data Acquisition Wake up Sequence The amp 7 7 analyzer continuously executes a FFT of the input signal As long as there is no signal or any non correlated audio information no action is started But as soon as the analyzer detects a header i e the 7 7 specific frequency level pattern in the input signal it wakes up and records the incoming multitone signal Please notice that the trigger signal can be detected up to 20dB below the set range That means for example with an input range set to 6dBu the trigger can be detected from levels as low as 26dBu Synchronization Mode Normally the analyzer of 7 7 uses the internal sample frequency clock of the generator This mode should be used for all applications where no frequency shifts occur on the signal transmission path However in cases where the device under test DUT changes the frequency of the transmitted signal the analyzer has to synchronize itself onto the incoming signal itself For this purpose each header of a multitone burst contains a SYNC block providing a fixed frequency onto which the analyzing DSP may synchronize its sampling clock This feature and the choice whether a header shall be transmitted
47. er value isolate Y value isolate Y value convert Y string to value delete the read XY pair from string find next X Y separator NEUTRIK CORTEX INSTRUMENTS V 3 32 15 71 RTM Multitone Audio Test System User Manual 3 SYSTEM DESCRIPTION Multitone Signals Traditionally audio testing stimulates the device under test DUT with a sinusoidal signal This type of signal is relatively easy to handle and distortion measurements may be performed by simply notching out the single frequency Amplitude Amplitude dB 0 20 30 40 50 60 Kail 80 90 1 L L 1 100 i 0 10 20 30 40 50 60 70 80 90 0 5 1 1 5 2 Tme ms Frequency kHz Fig 9 Time Plot of Sinusoidal Signal Fig 10 Spectrum of Sinusoidal Signal More advanced tests like intermodulation distortion measurements stimulate the device with a pair of sinusoidal signals to come closer to the real situation of audio signal transmission In the presence of nonlinear transfer characteristics the DUT generates new harmonic and intermodulation frequencies However in practice the device is normally stimulated by music or speech which is a far more complex signal than any single or twin tone test Many frequencies with non correlated phase relations exist in such a real world signal Therefore multitone testing is a much more realistic approach for audio testing emulating the complex structure of nat
48. erea id 46 INPut TRIGgeE BREAK eeneg Seege deed eei ee e dele aedis 47 INPut TRIGger CONFiguration LOOSE TIGHTIUSER sees 47 INPut TRIGger USRConfiguration lt setbin1 qdB gt lt setbin2 dB gt lt emptybin dB gt s ssssessesssssssserrrrrrsssrrrrrrne 47 INPut TRIGger USRConfiguration o cito da 48 INPUT IE STA E 48 OUT Put Subsystem sce stron ce a ae e e aa mote 49 OUTPut MTONe PARameter Parameter 49 OUTPut 1 2 LEVel Level lt Unit gt rre eee 49 OUTPut MTONe PRETriggerlength Length 50 OUTPut MTONe MTONelength Length 50 OUTPut 1 2 BlNlevel Level Ulm 51 OUTPut 1 2 MUTe OFFION iret eee et ote RR e ECH 51 ER MR De OAT OFA ON ENEE 51 OUTPut M TONG AC live 1125314 Li cusco det 52 GUTPUEMTONS STA Risa lic 52 OUTPUUtMTONS CONITIRUOUS i saa cn seas eege sv e ou cu stead aaa de 52 OUTPut 1 2 STATUS ois te p e aei enum 52 DOUTPUEMIEONSINAME P oake ioco nte po Decretos eae txt epe rhet rd 53 OUTPurMTONS BLOGCKlengili tont tort ortis 6 tuat iori ter Roe me etc 53 OUTPut MTONe PARamlieter Die ted ee ci 53 OUTPut 1 2 MTONe CRESt eere ter eec xem tes tuere gens 54 MEASurement SUDSyVSIGITI osas 55 MEASurement 1 2 LEVel UNIT dBVp VpldBVIV eeeeeeeeeeeeeeeeeeeeeeeeeeenaaees 55 MEASurement 1 2 LEVel cio ties der terere e een pande en un 55 MEASurement 1 2 DISTortion UNIT IOBVIVTL 55 MEASurement 1 2 DISTortion ue 55 MEASurement T2 MISMA Proa eei egt ed a tee Rt cum ees 56 MEASurement 1 2
49. error n3 number can be read with the lt system errors gt query Not used n Not used n Operation complete event flag This event bit is generated in response to the OPC No command It indicates that the device has completed all pending operations Enable value Byte 0 to 255 E ESR gt B 32 command error has occurred The Power on Status Clear command controls the automatic power on clearing of the service request enable register and the standard event status enable register lt PSC 0 gt no power on clearing of the registers lt PSC 1 gt power on clearing of the registers and therefore disabling of service request assertion after power on See also chapter IEEE Standard Status Data Structure lt Enable_value gt Byte Oto 1 0 e PSC 0 PSC The Power on Status Clear query allows the programmer to query RT 1M s power on status se query prog query p NEUTRIK CORTEX INSTRUMENTS 62 71 V 3 32 RTM User Manual Multitone Audio Test System Parameter Range Example IDN Use Parameter Example clear flag See also chapter IEEE Standard Status Data Structure lt PSC 0 gt no power on clearing of the registers PSC 1 gt power on clearing of the registers and therefore disabling of service request assertion after power on lt Power_on_flag gt Byte 0 not cleared 1 cleared Boa PSC E 0 The IDentificatioN query g
50. ets the unique identification of RT 1M See also chapter IEEE Standard Status Data Structure Manufacturer string Instrument type string Serial number string 4 Firmware revision float gt TDN 2H NEUTRIK RT1M 0122 3 01 RST Use Parameter Example TST Use Parameter Range Example WAI The ReSeT command performs a device reset All Parameter are set to default values except the output and command queue See also chapter IEEE Standard Status Data Structure No Parameter RST D v The self TeST query causes an internal self test and places a response into the output queue indicating whether or not RT 1M completed the self test without errors Self test Byte 0 errors occurred 1 self test OK H gt TST gt H 1 Use The WAIt to continue command prevents RT 1M from executing any further commands or queries until the no operation pending flag is TRUE However since RT 1M has implemented only sequential command execution the no operation command flag is always TRUE NEUTRIK CORTEX INSTRUMENTS V 3 32 63 71 RTM Multitone Audio Test System User Manual il Example B gt WAI Examples Use of an OPC command The OPC and WAI commands and the OPC query allow the controller to synchronize itself to the end of a calculation performed by 27 11 lH esr clears previous events
51. expressed Range dBV iV string Default dBV Example Ho MEAS1 DIST UNIT V MEASurement 1 2 DISTortion Use Returns the distortion values of all the bands between Bin Min Bin 1 Bin 1 gt Bin 2 etc Bin n gt Bin Max see also Distortion Answer Bin Min integer Dist float string Set bin n integer Dist n float string NEUTRIK CORTEX INSTRUMENTS V 3 32 55 71 RTM Multitone Audio Test System User Manual Range Bin_Min Bin_Min Set_Bin_n Bin_Min to Bin_Max see Equation 4 and Equation 5 Dist 1 Dist n float NaN string Unit Defined in MEASurement 1 2 DISTortion UNIT Example B gt Measurementl Dist gt H 3 2 23E 2 V 11 8 23E 3 V 27 1 35E 2 V Explanation The returned distortion vector starts with the number of the first bin 220Hz the distortion up to the first signal bin Second pair is the number of the first signal bin the distortion result between this first signal bin and the second signal bin etc The last pair is the last signal bin the distortion result between this last signal bin and Bin_Max last bin lt 20kHz see Fig 20 If a band between two signal bins is too narrow to measure a distortion NaN is returned MEASurement 1 2 MTSinad Use Returns the SINAD value using the selected Multitone signal in the full bandwidth between Bin Min gt 20Hz and Bin Max lt 20kHz The single value calculation considers Signal plus Distor
52. fer to the active signal Range 1121314 integer Default 1 Query Use command OUTPut 1 2 STA Tus Example H OUTP MTON ACT 2 E gt Output Mtone Active 1 OUTPut MTONe STARt Use Start transmission i e generation amp analysis of the active multitone burst Example BO OUTP MTONE START Explanation This command has to be sent either if a multitone burst shall be e generated and analyzed or e generated only or e sampled amp analyzed only OUTPut MTONe CONtinuous Use Example Explanation Starts the generator to endlessly send out the active multitone signal a OUTP MTONE CON The signal is sent out in an endless loop Only the multitone signal is transmitted i e without header No measurement may be performed on this signal This is a generation mode only The signal can be stopped by any IEEE command being sent to RT 1M OUTPut 1 2 STATus Use Queries the generator status for channel or channel 2 Answer lt Active gt string ACTIVE 1121314 lt Out_Level gt string LEVEL 60 to 20 dBVp 0 001 to 10 Vp lt BinLevel gt string BINLEVEL 60 to xx dBVp 0 001 to yy Vp lt Mute_State gt boolean MUTE ON i OFF lt Float_State gt boolean FLOAT ON OFF Resolution lt Out_Level gt 0 1dBV Example B gt OUTPUT1 STATUS gt B ACTIVE 1 LEVEL 3 5000E0 dBV BINLEVEL 0 1 V MUTE OFF FLOAT ON NEUTRIK CORTEX INSTRUMENTS 52
53. g Explanation The returned result is composed of pairs each starting with the signal bin number followed by a the phase result a white space the unit in which the phase was measured and a H MEASurement1 DTMF STARt Usage Resets the DTMF tone receiver buffer 32 keys wide of channel 1 NOTE This command requires installation of the DTMF option for RT 1M Examples Eo Measl Dtmf Start Explanation After this command RT 1M continues to store all incoming DTMF tones in its buffer MEASurement1 DTMF Usage Queries the DTMF tone receiver buffer 32 keys wide of channel 1 NOTE This command requires installation of the DTMF option for RT 1M Examples El MEAS1 DIMF gt B 1 2 2 3 2 2 3 keys detected 2 8 5 Explanation RT 1M returns pairs of x y coordinates identifying the DTMF keys in the received order The standard 4x4 keypad coding is Ly coord 1 2 3 4 xcoord unused fields may be user defined 1 1 2 3 A 2 4 5 6 B 3 7 8 9 C GE NEUTRIK CORTEX INSTRUMENTS V 3 32 59 71 RTM Multitone Audio Test System User Manual Device Status STB Use Fetches the STatus Byte register See also chapter IEEE Standard Status Data Structure Calculation STB n 128 ng 64 n 32 n 16 n3 8 n 4 n 2 ng n7 Not used De Master summary status MSS The MSS message indicates that RT 1M has at least one reason for requesting service ns Event
54. g Af may be transmitted Frequency Spacing The frequency spacing Af corresponds to the lowest frequency that can be generated 8 analyzed It defines the spectral resolution of the FFT and is calculated by following formula Sampling frequency 48000Hz Af Blocklength Blocklength Equation 3 Frequency Spacing NEUTRIK CORTEX INSTRUMENTS 18 71 V 3 32 RTM Multitone Audio Test System User Manual Only frequencies with an integral multiple of Af may be defined as signal bins see below of a multitone burst Example Blocklength 512 48kHz sampling rate gt Af 93 75Hz gt available frequencies n 93 75Hz n integral number Bins The frequencies that may be transmitted in a multitone burst are called bins For a better understanding three types of bins have been introduced e Signal bins are those bins frequencies that actually build the multitone signal e Even bins are all the bins frequencies that emerge from Equation 3 i e the frequencies that may be used as signal bins in a multitone signal e Odd bins are an effect the internal FFT computation of 47 14 They represent all bins halfway between the even bins i e as if the frequency spacing would equal Af 2 The subsequent relations indicate the min and max available frequencies bins in a multitone signal at 8kHz 48kHz sampling rate fs f min Af 2 20Hz may be generated only Equation 4 Minimum Signal Bin Frequency 20kHz Af
55. he trigger must have been generated by another 7 7 instrument and has to match the trigger conditions defined in the analyzing unit Setup The complete procedure to set up a broadcast transmission test with 47 may be summarized as follows 1 Install the generator and analyzer at the intended locations and control each of them with an own PC through GPIB IEEE interfaces 2 Connect the two units with the ends of the transmission line to be measured 3 Write an appropriate program to control the units Optionally you may also install RT EVAL V1 60 or higher on both host PCs 4 Define a multitone signal according to the specific demands of the test available bandwidth number of bins signal duration etc identically on both the generator and analyzer Don t forget to optimize the Crest factor of the signal e g by using the Crest optimizer of RT EVAL 5 In the analyzer set the trigger configuration to TIGHT by using command INPut TRIGger CONFiguration LOOSETTIGHTWIUSER 6 Setthe SYNC mode of the generator to INTernal with command INPut SYNC INTernal 7 Setthe output level of the generator approximately to the level of the broadcast signal Make sure that no clipping occurs 8 Setthe SYNC mode of the analyzer to EXTernal with command INPut SYNC EXTernal 9 Adjust the input range of the analyzer to the incoming signal level To do this connect the analyzer to the transmitted broadcast signal and reduce the input range unt
56. il the Overload LED lights up Increase the input range by 6dB from this value in order to provide enough headroom 10 Set the analyzer to the armed mode with command INPut TRIGger ARMed 11 Interrupt the broadcast signal and transmit the multitone burst with command OUTPut MTONe STARt NEUTRIK CORTEX INSTRUMENTS V332 35 71 RTM Multitone Audio Test System User Manual 12 It is recommended to transmit the burst at a defined time so that the operator of the analyzer realizes immediately whether the trigger has been detected or not If no successfull line measurements are possible read the chapter Application Hints Troubleshooting p 37 to check possible causes and work out solutions Trigger Configuration The most important topic of broadcast mode measurements with 7 7 is the definition and application of an appropriate trigger For this purpose three trigger configurations are provided e LOOSE standard configuration for industrial applications noisy signals with a poor dynamic range or internal link between generator amp analyzer The trigger condition is met rather easily i e false triggerings have to be expected if the multitone signal is introduced into an ordinary broadcast program etc e TIGHT special configuration for broadcast applications The trigger condition has been tightened by far vs LOOSE in order to avoid false triggerings Requires an accurate setting of the generator output level and analy
57. in Max Greg 20kHz 48 000 Hz 48 000 Hz Use command OUTPut MTONe PARameter Ea gt Output Mtone Par 1 Telefon 2048 3 3 25 85 256 25 85 256 0 1 5707 r3 14 0 1 5707 3 1415 This command defines all compulsory parameter of a new multitone signal No Of Bins CHX equals the total number of signal bins for channel 2 Bin No X CHY indicate the bin numbers as calculated with Equation 7 p 25 Phase X CHY indicate the phases of the signal bins OUTPut 1 2 LEVel Level Unit Use Parameter Unit Range Set the total output level of the multitone signal Level float Unit string dBVp Vp dBV V V Peak value in logarithmic scale RMS value is lower by crest factor dBV Peak value in linear scale RMS value is lower by crest factor Vp RMS output level in logarithmic scale peak level is higher by crest factor dBVp RMS output level in linear scale peak level is higher by crest factor 60 to 20 dBVp rounded to nearest 0 1dBVp 0 001 to 10 Vp V 3 32 NEUTRIK CORTEX INSTRUMENTS 49 71 RTM Default Query Example Explanation Multitone Audio Test System User Manual 0 dBVp Use command OUTPut 1 2 S TA Tus B gt Outpl Level 6 2 dBVp Fi OUTPUT2 LEVEL 3 5 V This command allows to set the output level in either RMS or peak units The maximum output level of 10Vp cannot be exceeded OUTPut MTONe PRETriggerlength
58. ion Plot Full Band TD N Measurement To evaluate the TD N value in the full frequency band 20Hz 20kHz following equation has to be applied TD N fang JD v D V D vV Equation 10 Full Band TD N wherein D D are the returned distortion results expressed in V THD N Calculation To evaluate the THD N value of a DUT the following requirements have to be met e Stimulation of the DUT with a single bin signal e Calculation of the THD N value in 96 according to 2 2 THD N 46 Z DIVI S 100 JDP L IVP D VY Equation 11 THD N Calculation with D distortion between 20Hz and the signal bin Dz distortion between the signal bin and 20kHz and L received signal bin level MT SINAD For some applications the SINAD result being the reciprocal of THD N is required Signal Noise Distortion SINAD Noise Distortion Equation 12 SINAD Definition NEUTRIK CORTEX INSTRUMENTS 30 71 V 3 32 RTM Multitone Audio Test System User Manual Obviously to get a true SINAD result it is necessary to stimulate the DUT with a single sine tone only Otherwise i e if a multitone signal is applied intermodulation products would appear thus increasing the Noise Distortion value Nevertheless it is also possible to calculate the SINAD result out of a transmitted multitone signal However in order to avoid misunderstandings this result is called MT SINAD herein Actually with 7 7
59. l Analog Section The two channel analog output signal behind the D A converters is fed into a reconstruction filter cutting off all frequencies above 20kHz On its way the signal also passes through an electrical isolation to keep the complete analog output section floating The programmable output amplifier offers a balanced signal with 150Q output impedance unbalanced 75Q at any level in steps of 0 1dB between 60dBVp to 20dBVp Analyzer The amp 7 7M analyzer consists of a two channel analog input stage preparing the input signals for the conversion into digital format With the converted signals an FFT analysis with the NEUTRIK CORTEX INSTRUMENTS 22 71 V 3 32 RTM Multitone Audio Test System User Manual same blocklength as of the generated signal is performed Further analysis of the acquired result may be done through individual programming Additionally the analyzer also provides facilities to weight an input result with different weighting curves Block Diagram AMP gt A D CONVERTER AMP gt A D CONVERTER DSP p d Wa e 0 00 CLOCK SYNC LED INDICATORS CPU IEEE 488 INTERFACE DSP MEMORY Fig 17 Block Diagram Analyzer Analog Section FT features two independent analog input stages with completely independent ranging facilities The inputs are balanced with BNC and 4mm banana c
60. le generator as well as an intelligent analyzer and can be easily integrated into an automated environment The system provides the highest performance and specifications to meet also the requirement of professional equipment e Frequency range 20Hz to 20kHz e Output level 60dBVp to 20dBVp e Input range 60dBVp to 20dBVp e Measurements level noise distortion crosstalk and phase in one step e Burst transmission time typ 250 960ms e Residual distortion lt 86dB RT is very simple in terms of connecting handling and use within any automated environment but highly complex in terms of the implemented structures and algorithms to perform the analysis in a extremely short period of time amp 7 1 f is very compact using the most advanced technology available on the market Within its case of 19 width and height of one unit 1 75 only it provides two generator channels and two independent analyzer channels The analyzer and generator can be operated completely independently even though they are located in the same housing There is no external synchronization required to perform the analysis Each transmitted multitone signal contains an information header allowing any listening analyzer to synchronize onto the signal Communication Since 4 f does not provide any control elements it must be completely controlled by a host PC Due to performance reasons an IEEE 488 parallel interface has been integrated into the instrument
61. ling rate is 48kHz thus providing an analog bandwidth of up to 20kHz NEUTRIK CORTEX INSTRUMENTS V 3 32 17 71 RTM Multitone Audio Test System User Manual Blocklength The number of samples that are actually used for one FFT is called blocklength This value determines both the duration amp the frequency resolution of a multitone signal In 7 7 the blocklength may be selected by the user in five steps from 512 to 8192 Blocklength MT Block Duration s Sampling_ Frequency Equation 2 Duration of One Multitone Signal Block Note A 47 multitone burst always comprises several multitone signal blocks thus resulting in a far longer duration than the MT Block Duration The blocklength also defines the lowest detectable frequency of the incoming spectrum For example with a blocklength of 512 48kHz sampling rate a multitone block duration of 10 7ms results corresponding to a min frequency of Af 93 75Hz see Equation 3 Furthermore it is important to know that only signals with an integral number of periods reciprocal value of the signal frequency fitting into one blocklength may be properly analyzed by the FFT 0 100 200 300 400 500 Sample Number Fig 13 The 5 Lowest Possible Time Periods Blocklength 512 In other words only frequencies with an integral multiple of the lowest detectable frequency called frequency spacin
62. ll lar Phone Testigos aeu EE locas 66 Rub amp Buzz Speaker Tesla naaa 66 RT EVAL Software Package 3 E e D ds 67 Units amp Conversion 40 6 ool oo bird dh oi TM 67 ECHTER ee eege 69 Creme TRE 69 A sa io hae oe ai eoe eO dp ete ot pete dea d da dated 69 Te Ve ieee ete I ARIS ANT IIS HINT DIS mira DT ONT RI TERN NT E Ut 69 T INDEX emt EN 70 8 71 NEUTRIK CORTEX INSTRUMENTS V332 RTM Multitone Audio Test System User Manual 1 OVERVIEW The trend in modern audio testing is to reduce more and more the time required for a complete performance test of the device being tested This tendency results partly from the demand of broadcasters being forced to provide 24hour programming leaving little time for testing In a modern studio with dozens of input channels several routing paths and more than 24 recording channels a complete test including all parts of the studio becomes very time consuming and boring since the tests are highly repetitive Industrial applications also require reduced test time especially at production lines where any time wasting process becomes a bottleneck Reducing test time by a factor of 20 to 50 ensures for years that testing will not be the limiting factor and increases production density T is a modern and advanced audio test system with the capability to evaluate the important performance Parameter of a device within a fraction of a second 47 f is a complete optimized system containing a remote controllab
63. n Set the bin level of the multitone signal all bins have equal level lt Level gt float lt Unit gt string dBV IBV dBVp Vp dBV RMS binlevel in linear scale V RMS binlevel in logarithmic scale dBVp Peak value in linear scale Vp Peak value in logarithmic scale 60 to xx dBVp max binlevel has to be calculated acc Equation 1 amp Equation 6 0 001 to yy Vp Use command OUTPut 1 2 STA Tus E gt Outpl Binlevel 6 2 dBVp Be aware that when bin level is set the total output level is higher as per Equation 6 The maximum output level of 10Vp cannot be exceeded OUTPut 1 2 MUTe OFF ON Use Range Default Query Example Mute or unmute a channel output OFF i ON boolean OFF Use command OUTPut 1 2 STA Tus EH Outputl Mute ON Ea gt OUTP1 MUT OFF OUTPut FLOAT OFF ON Use Sets both output channels to either float or ground mode In float mode the center tap of the generator can float to any level Ground mode is necessary for unbalanced output signals Range OFF ON boolean Default OFF Query Use command OUTPut 1 2 S TA Tus Example d Output Float ON NEUTRIK CORTEX INSTRUMENTS V 3 32 51 71 RTM Multitone Audio Test System User Manual OUTPut MTONe ACTive 1 2 34 Use Defines the current multitone signal as the active signal used for transmission All commands with no signal number re
64. n which way 47 actually calculates the TD N values in the frequency bands of interest The answer can be given by considering the equations for the RMS and RSS value RMS and RSS Value Purely analog test instruments evaluate the distortion energy as RMS voltage Root Mean Square by summing up all received signal components V according to following equation NEUTRIK CORTEX INSTRUMENTS 28 71 V332 RTM Multitone Audio Test System User Manual EE i l n Vig with n 2 number of signal components n Equation 8 RMS Calculation Unfortunately when applying this formula on the discrete spectrum of a FFT analysis the result correlates in inverse proportion to the blocklength number of bins in the respective band Therefore to calculate the TD N result out of a digitized signal the RSS value Root Sum Square has to be used Vass Y v Y with i counter over all bins n m Equation 9 RSS Calculation The accuracy of this approach can be proved with any spectral analyzer The better the resolution i e the higher the blocklength the lower is the amplitude of a single bin since the total energy of the band is constant Consequently the summing up of the bins always result in the same value regardless of the chosen resolution blocklength Interpretation of TD N To interpret the TD N value correctly it has to be considered that this result slightly differs from a conventionally measured THD N value With conve
65. ne arbitrary 16bit 48kHz 5 86Hz blocklength 8192 4 stereo 1 to 31 20Hz to 20kHz 260ms to 960ms depending on frequency resolution max up to 30sec or continuous programmable lt 86dB or 10uV 60 to 20 dBVp in 0 1dB steps for each channel individually 0 2dB 1kHz 0 2dB 20Hz to 20kHz Level Total Distortion Noise Interchannel Phase Crosstalk measured simultaneously 2 18bit 48kHz lt 860B input signal gt 15dBVp 2 95Hz minimum 60 to 20 dBVp lt 0 2dB 1kHz 0 2dB 20Hz to 20kHz Internal or External 800ms blocklength 512 and 3 signal bins 483 x 318 x 44 mm 19 x 12 5 x 1 75 1 rack unit high 7kg IEEE 488 100 120 230V 50 60Hz 60VA 1 year recommend calibration interval 5 to 45 C 40 to 110F with R H lt 90 non condensing NEUTRIK CORTEX INSTRUMENTS V 3 32 69 71 RTM Multitone Audio Test System User Manual 7 INDEX A E AC Power Connection 11 Error LED Indicator 14 Accessories cceeceeeceeeceeeceeeceeeceeneees 10 Evaluation Software 10 Address Selection 12 Even Bim 19 Analyzer EXT voii iaa da 27 Block Diagram sssesssss 23 EXTNoheader een 27 FilletS ct e els enr 23 Application Hints 10 37 66 F B EP Tae tte ot ett tees EE 17 FISCO cocoa 23 Balanced Connecti
66. nstalled internally allowing to monitor 1 channel on incoming DTMF Double Tone Multiple Frequency signals in parallel to the normal operation see p 34 Microphones amp Phantom Power Supply NEUTRIK provides two measuring microphones for industrial applications e 3382 measuring microphone e 3384 12 measuring microphone To allow the use of these microphones with X7 1 an optional Phantom power box is available to provide the necessary supply voltage through XLR connectors The box is plugged to the input banana connectors and comes along with an AC mains adapter NEUTRIK CORTEX INSTRUMENTS 10 71 V332 RTM Multitone Audio Test System User Manual 2 INSTALLATION This chapter is intended as help for proper unpacking and installation of the 7 7 7 system Please read it carefully to avoid wrong connections or inconveniences during operation of the instrument Unpacking FT has been carefully packed by NEUTRIK to avoid damages during transportation Should the box show severe damages please immediately check the instrument inside on external impacts In case of any visible damage please do not send the instrument back but contact your local dealer and or the carrier to avoid loss of claims for replacement Rack Mount FT is designed to mount in a 19 Rack and occupies one unit of height or rack space 1 75 only Please allow at least 2 additional depth at the rear side for all necessary connectors Make sure there i
67. ntional THD N analysis a single tone stimulates the DUT This frequency component is subtracted from the received signal after transmission The ratio of the remaining level to the total input level gives the THD N and SINAD result respectively On the other hand the transmission of a multitone stimulus will result in the appearance of many harmonics and intermodulation products However it is neither possible to relate any of these signal components to a certain signal bin of the original multitone signal nor to differentiate the received signal between harmonics and intermodulation products Distortion Plot Fig 20 shows a typical distortion plot derived from the returned distortion results of amp f e The first value in the plot D1 equals the RSS result TD N value of the band between the first bin 220Hz up to the last bin SignalBin 1 e All further results Dn represent the bands between the first bin gt SignalBin n up to the last bin SignalBin n 1 e The last distortion result represents the band between the first bin above the highest signal bin up to the last bin lt 20kHz Please notice that both the even amp odd bins of the received signal are considered for the TD N calculation NEUTRIK CORTEX INSTRUMENTS V 3 32 29 71 RTM Multitone Audio Test System User Manual Amplitude Bin win Bina d Signal Signal Bin 3 Bing Signal Bin n Signal Bin 1 Frequency Hz Fig 20 Distort
68. oaded and therefore can t recognize the in coming trigger Distortions noise or sound enhanc ing effects modify the trigger sig nal in a way that it can t be rec ognized any more by the analyzer Analyzer triggers correctly but can t acquire a reasonable result User Manual Increase the generator output level or decrease the ana lyzer input range stepwise Reduce or attenuate genera tor output level Increase input range of ana lyzer stepwise Switch Off all sound enhanc ing systems during the transmission of the multi tone burst Set the identical signal bins in the active multitone signal of the generator amp analyzer Table 8 Broadcast Mode Troubleshooting 38 71 NEUTRIK CORTEX INSTRUMENTS V 3 32 RTM Multitone Audio Test System User Manual 4 PROGRAMMING Communication via the IEEE 488 interface allows complete remote control for all functions of RTM Command Structure IEEE 488 1 Compatibility The IEEE interface function set implemented in 7 The compatibility level is given in Table 9 Function TT Notes Source handshake Complete capability Acceptor handshake So Complete capability Talker T6 No talk only mode Talker extended TEO No capability Listener L4 No listen only mode Listener extended LEO No capability Service request SR1 Complete capability Remote local RLO Only local lockout Parallel p
69. oll PPO No capability Device clear DC1 Complete capability Device trigger DTO No capability Controller CO No capability Table 9 IEEE 488 1 Compatibility IEEE 488 2 Commands T M currently does not support all IEEE 488 2 commands These might be implemented at a later state Command Summary Following commands are currently available to control 7 77 system The commands are divided into four subsystems Subsystem Function in RT 1M SYSTEM Control of RT 1M INPUT Control of analyzer input section OUTPUT Control of generator output section MEASUREMENT Query for measurement results Device Status Table 10 Subsystem Definition Most of the Parameter have to be completed with channel or signal information SYSTem RESet MEASurement LEVel UNIT NEUTRIK CORTEX INSTRUMENTS V332 39 71 RTM SYSTem SYSTem INPut INPut INPut INPut INPut INPut INPut INPut INPut INPut INPut INPut INPut OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put OUT Put Descriptive Symbols ERRors INFormation FRONt LINK RANGe SYNC SWEilter DEEMphasis TRIGger TRIGger TRIGger TRIGger TRIGger TRIGger STATus MTONe MTONe LEVel BINlevel MTONe MTONe FLOAT MUTe MTONe MTONe MTONe MTONe MTONe MTONe STATus Multitone Audio Test System ARMed ARMed BREak CONFiguration
70. on 12 13 Frequency Response 28 Battery Mel EN 13 Frequency Spacing IMS SAK cdo a Pty 18 Bin Full Band s ea en e oae 30 Amplitude VawesaaredsasuxasverredrrecrursaHsszarrser aW ra 25 Noise Measurement pU MEER 32 Number RU 25 TD N Measurement EE E G 30 Types E A a 19 THD N Measurement REIP ane 30 Blocklength ode ns 18 20 Funcion Test tees 15 BNC Cables aanainenenennennennenerrnrrerreenne 13 Broadcast Mode 35 G Burst Duration 20 Generator eeeseeeeneneene 22 C Analog Section suus 22 Block Diagram sees 22 Calculating LED Indicator 14 Digital Section esses 22 CE Conformity eid ee eeben 4 Signal Definition 24 Cellular Phone Testing Inani Ee Ponce 66 GPIB Board A A TT 10 Command Grounding 13 NOTATION cette eire 41 COMMUNICATION EE ar etd 9 H C bility of MT Si cto 2 OS A 25 Balanced ceci liada 12 HT BASIC 15 Unbalanced 12 Conversion of Units 67 Crest Faclor ea hainas 17 19 IEEE Crosstalk Measurement 33 Address Selection ss 12 Compatibility sees 39 D Connection ccccconoccccnccnnnnnnonananananancnnnnnnono 12 dB amp Related Units IEEE o ERE Descriptive Symbols in 40 Interface LED Indicator 14 Distortion INTernal 26 F ll Band iei 30 INTNoh 3d LN U
71. onnectors at the front and rear panel Input impedance is 100kQ at all inputs Levels can be handled from 60dBVp to 20dBVp with full dynamic range Filtering T M provides a set of software weighting and Emphasis filters The filters have a gain of 1 and can be disabled or enabled Only one weighting filter and the Emphasis filter may be engaged at a time The current filters implemented are listed on the next page NEUTRIK CORTEX INSTRUMENTS V 3 32 23 71 RTM Multitone Audio Test System User Manual EX C Message CCITT 750us Emphasis M The commands INPut 1 2 RANGe lt Range gt lt Unit gt and INPut DEEMphasis allow to select them Digital Section The digital section consists mainly of the DSP and a logic circuitry programmed into a FPGA The DSP is used for all calculations especially the FFT and to control the range setting of the analog input amplifiers The DSP is connected via a bus to the central processing unit which manages all communication to the PC and controls the system bus Definition of Multitone Signals T may store up to four independent two channel multitone signals with up to 31 frequencies in a non volatile memory This ensures that no programming or parameter loading is required before the generator can be operated New signals can easily be loaded into one of the memory blocks using an IEEE output command For the correct syntax please refer to OUTPut MTONe PARameter New signals must con
72. or implied in law or in fact including without limitation implied merchantability or fitness for any particular purpose and assumes no liability either in tort strict liability contract or warranty for products NEUTRIK AG Im Alten Riet 34 FL 9494 SCHAAN Liechtenstein Tel 41 0 75 237 24 24 Fax 41 0 75 232 53 93 WARNING Read this manual and especially chapter 2 NSTALLATION carefully before operating the instrument Important information about mains voltage selection and fuse rating are given there Do never open modify or try to repair this instrument unless properly instructed by an authorized service technician or NEUTRIK NEUTRIK CORTEX INSTRUMENTS V 3 32 3 71 RTM Multitone Audio Test System User Manual CE DECLARATION OF CONFORMITY We the manufacturer NEUTRIK CORTEX Instruments AG Im Alten Riet 34 FL 9494 Schaan hereby declare that the product Product Name Rapid Test Model Number RT 1M Serial No Year of Construction 1996 conforms to the following standards or other normative documents EC Rules 89 392 91 368 93 44 93 68 73 23 89 336 92 31 Harmonized Standards IEC 65 IEC 68 2 31 IEC 348 EN50081 1 EN50082 1 EN50140 EN 61010 1 This declaration becomes void in case of any changes on the product without written authorization by NEUTRIK Date Schaan 12 August 1996 Signature Position of Signatory Product Manager Test Instruments Samples of this instrument have be
73. ppendix of this manual Signal Table amp 7 4 f supports five different blocklengths According to Equation 3 to Equation 5 each blocklength results in the parameter of Table 1 Please observe that the minimum signal bin frequency is 220Hz and that the overall duration of a burst always is longer than of a block Blocklength Min Burst Duration Typical Burst Generator Analyzer without Header Duration Resolution Resolution 512 154 ms 260 ms 93 8 Hz 46 9 Hz 1024 284 ms 390 ms 46 9 Hz 23 4 Hz 2048 344 ms 450 ms 23 4 Hz 11 7 Hz 4096 684 ms 790 ms 11 7 Hz 5 9 Hz 8192 854 ms 960 ms 5 9 Hz 2 9 Hz Table 1 Available Blocklengths Blocklength 512 Frequency spacing Af 93 75 Hz Analyzer resolution 46 875 Hz Bin Min fmin 1 93 8 Hz Bin Max fmax 213 19 969 kHz Table 2 Signal Parameter with Blocklength 512 O f 4SkHz NEUTRIK CORTEX INSTRUMENTS 20 71 V 3 32 RTM Multitone Audio Test System Blocklength 1024 Frequency spacing Af 46 875 Hz Analyzer resolution 23 4375 Hz Bin_Min fmin 1 46 9 Hz Bin Max fmax 426 19 969 kHz Table 3 Signal Parameter with Blocklength 1024 f 48kHz Blocklength 2048 Frequency spacing Af 23 4375 Hz Analyzer resolution 11 71875 Hz Bin Min fmin 1 23 4 Hz Bin Max fmax 853 19 992 kHz Table 4 Signal Parameter with Blocklength 2048 f 48kHz Blocklength 4096 Frequency spacing Af 11 71875 Hz Analyzer resolution 5 859375 Hz Bin Min fmin 2 23 4 Hz Bin Max fma
74. r TON ee 97 Meaeurement 28 EES PlOUx in icit e ins 29 Driver Library AAA 10 L GE Mode en 34 LED Indicators 14 uration Level Measurement 28 of Multitone Burer 20 LOOSE Trigger 36 f Multit Si sce a m eni hd eie d8 EE n ne A E EE E SP a oie US Low Battery Indicator 13 NEUTRIK CORTEX INSTRUMENTS 70 71 V 3 32 RTM M Mains Cable eene 12 Microphones AEN 10 MT SINAD eeermm HH 30 Multitone Background re 16 Burst Structure esses 24 Parameter secs e use eie Eee 17 Tel 26 N Noise Full Band Measurement 32 Noise Measurement 32 O Odd BIISs rer eoe rere 19 OPTIONS soci rte C e aod ed 10 Overload LED Indicator 14 OVV EW meme 9 P Phantom Power Supply 10 Phaser th 19 Phase Measurement 34 Power LED Indicator 14 Program Example 15 Programming seen dara 39 R Rack Mount 11 RMS Value eren 29 RSS Selective Measurement 31 M alU8 cea E 29 ESSEN ee Age 67 Rub 8 Buzz Testing 66 S Sampling Hate sseeseeneeeeeeeeeserereeen 17 Advanced Multitone Audio Test System Signal BIS one tte ica 19 Definition iens 24 SINAD E 30 Softwar
75. response of the DUT With the multitone approach this goal is achieved in one step by measuring the returned signal bin levels instead of sweeping a single sine signal through the frequency band of interest In practice the frequency response can be obtained from a transmitted multitone signal by plotting the received signal bin level values Please notice that this analysis considers the energies of the signal bins only but not the distortion noise energy in the bands between the signal bins Amplitude Returns levels of set bins only Bin Mp Signal Signal Bin 3 Signal Bin 1 Frequency Hz 20 20k Fig 19 Level Plot Keep in mind that the overall input level i e the total energy of all received signal bin unused bin levels would correspond to the RMS level of the received multitone signal signal bin levels distortion noise However this value is of almost no interest for the characterization of a DUT since it reflects its overall attenuation amplification only but not the frequency response Distortion Basically distortion is a measure to characterize the nonlinear behavior of a DUT i e the degree of how it generates new signal components at other frequencies than the one s of the stimulating signal Therefore The 47 returns as distortion results the total distortion noise energies TD N for the bands between the signal bins of a multitone signal Remains the question i
76. rnally generated incoming multitone burst with trigger Use commands INPut TRIGger ARMed and INPut 1 2 STATus Bo Inp Trigger Armed This command allows the analyzer to receive multitone bursts that have been generated by a remote RT 1M unit i e to run the analyzer in the so called Broadcast Mode In the armed status the Trigger LED will be flashing until a trigger is detected LED is lit Keep in mind that for broadcast applications it is necessary to set the synchronization mode of the generator analyzer to INTernal EXTernal while the trigger configuration for both units must be TIGHT see p 3 36 INPut TRIGger ARMed Use Queries whether RT 1M is in the armed mode Answer lt Trigger_Status gt Range ARMED i STOPPED string ARMED As long as RT 1M is in this mode it will wait until an incoming multitone burst is detected or until the unit is re set into the normal operation STOPPED This status indicates that RT 1M is not armed i e waiting for a trigger but in the normal mode In this status the Trigger LED will be dark Example Bo Inp Trigger Armed gt 8 ARMED NEUTRIK CORTEX INSTRUMENTS 46 71 V 3 32 RTM Multitone Audio Test System User Manual INPut TRIGger BREak Use Disables the armed mode of RT 1M i e re sets the unit into the normal mode Query Use commands INPut TRIGger ARMed and INPut 1 2 STATus Example BO Inp Trigger Break Explanation This command returns
77. s enough air circulation around the unit for cooling purposes and please do not place 47 besides high temperature devices such as power amplifiers in order to avoid overheating The specified operating temperature ranges between 5 and 45 C 40 110F while humidity must not exceed 90 R H non condensing AC Power Connection Before connecting the instrument via mains cable to the power source make sure that the voltage selector label on the connector fuse holder assembly of the 7 7 system matches the supply voltage of the local area If the instrument is not compatible with the available power source follow the next paragraph to change the voltage selector K7 1 f can operate from 100VAC 120VAC and 230VAC sources To reconfigure the input line voltage remove the power cable and open the flap of the connector fuse holder at the rear side of 7 7 Either press a small screwdriver into the slot to open the flap as shown in Fig 1 Fig 1 Voltage Selector or ruin your fingernails Take out the drum and insert it in the new position so that the matching voltage indication points towards you At the same time replace the mains fuse with the proper current rating For voltages of 100V to 120V a slow 2A fuse has to be installed while for 230V a slow 1A fuse is appropriate After selection of the correct mains voltage and fuse close the flap and insert the power cable amp 7 f is designed with a protective ground earth
78. s in an arguments list Used to indicate a range of suffixes available gt String is sent from the controller to RT 1M y El Returned string from RT 1M to the controller Table 11 Symbol Description T accepts only the short or the exact and full form of the statements Sending a command that is neither will generate an error In following command list the CAPITAL 40 71 NEUTRIK CORTEX INSTRUMENTS V 3 32 RTM Multitone Audio Test System User Manual letters indicate the short form to help reduce the required typing However the 7 7 parser accepts both lowercase and UPPERCASE commands i e it is not case sensitive Command Notation In the listing of amp commands descriptive headings are used to divide the information into easily readable parts The used headings and the contents are shown below If a heading does not apply on a command it is not listed Use What the command does and additional information is given in the heading Answer Lists the possible answers on a query and their types integer float boolean string Parameter Description of the Parameter to be set and their types integer float boolean string Range List of the available Parameter and their types integer float boolean string Default Description of the default parameter After a RESET all Parameter in an instrument are set to their default values Unit Specification of the available parameter units Re
79. solution Definition the step size of a Numeric Value Query Indicates the query command corresponding to the described command Example Command examples are provided here The short form and lowercase characters are used as a reminder that both forms are allowed Explanation Additional explanations and hints NEUTRIK CORTEX INSTRUMENTS V 3 32 41 71 R7 1M Multitone Audio Test System User Manual Command Set SYSTem Subsystem SYSTem RESet Use Example Explanation Initiates a software RESET All set Parameter in the instrument are re set to their default values Error queue is cleared a gt SYST RES a gt System reset The RESET command initializes the complete instrument including the IEFE interface Commands that are in the command buffer or those which are entered shortly after the RESET may be deleted by the RESET command and are therefore not executed SYSTem ERRors Use Answer Range Queries the number and types of errors since the last Query i Startup System Reset command lt Error_No gt integer 100 No subsystem separator found 101 No subsystem found 102 No command separator found 110 No SYSTem command found e g RESET 120 No INPut command found e g LINK 121 No INPut 1 2 command found e g RANGE 130 No OUTPut command found e g FLOAT 131 No OUTPut 1 2 command found e g LEVEL 132 No MTONe command found e g START 13
80. tain following information e 7 1 memory location to store the signal e Name of the signal e Blocklength number of samples e Number of signal bins for channel 1 e Number of signal bins for channel 2 e Signal bin numbers of channel 1 e Signal bin numbers of channel 2 e Phases of the signal bins for channel 1 e Phases of the signal bins for channel 2 The memory location may be defined by a number from 1 to 4 Name is a user defined ASCII string with up to 8 characters The blocklength has to be set to one of the values defined in Table 1 The number of signal bins defines how many frequencies shall appear in the multitone signal for CH1 and CH2 the minimum is 1 sinusoidal signal the maximum is 31 bins The signal bin numbers have to be calculated according to Equation 7 Two blocks of phase values for CH 1 and CH 2 terminate the definition of a multitone signal All signal bins have identical amplitudes The user has the choice either to set the overall output level of the multitone signal or alternatively the signal bin level Regardless of this choice these values may be expressed as peak or RMS levels in linear or logarithmic units Vp V dBVp dBV The overall output level of a multitone signal may be queried at any time The same goes for the actual Crest factor that may be queried with the command OUTPut 1 2 MTONe CRESt NEUTRIK CORTEX INSTRUMENTS 24 71 V332 RTM Multitone Audio Test System User Manual or calculat
81. the 2 channel test signal 9 QU je gU Pn Equation 16 Phase Calculation However the exact phase shift between generator output and analyzer input cannot be calculated due to the unknown time delay of the DUT DTMF Mode The DTMF option extends the measuring capabilities of 7 7 in the field of phone testing It allows to receive amp analyze the standardized DTMF Double Tone Multiple Frequency tones on channel 1 Every key of a standard 4x4 phone keypad is represented by a dual tone These tones comprise the indicated frequencies as shown in Table 7 697Hz 770Hz 852Hz 941Hz Table 7 DTMF Signal Coding For instance the DTMF tone for key 6 is put together of the two frequencies 770Hz amp 1477Hz The meaning of the four empty keys a d in the last row may be user defined The DTMF mode of G may be started and reset by using command MEASurementl DTMF STARt From then on the unit continuously monitors the input channel 1 in parallel to any other operation and stores all received DTMF tones in an internal buffer This 32 keys wide buffer may be queried by command MEASurementl DTMF To clear the contents of the buffer command MEASurement1 DTMF STARt has to be sent to the unit The input range of channel 1 must be adjusted to the level of the DTMF tones to be analyzed Please notice that an overload caused by an incoming DTMF signal will not be detected i e the unit will not generate an error message
82. tion of the analyzer Application Hints Troubleshooting To execute measurements in the broadcast mode is probably one of the more demanding procedures when working with 7 7 mainly because of the remote location between the generator and analyzer i e the sender and receiver of the multitone burst Nevertheless by considering both the instructions listed in chapter Setup p 35 and following hints it shouldn t become a major problem to establish a properly working set up e The most effective approach to successfully execute a first test run is to place the sender amp receiver not too far apart e g in the same room however with both units already being controlled by individual PCs Such a setup may probably not include a long transmission line but is ideally suited to adjust the required settings of the majority of the involved systems to allow a proper measurement e For the first signal transmissions measurements reduce the number of involved stages to a minimum to simplify the search for possible errors As soon as the first successful tests are completed the number of systems in the signal path may be increased stepwise and the respective settings may be optimized to the actual demands e A very helpful tool to find out possible problems is to use a monitor speaker to make the transmitted multitone burst audible at the different stages of the line Consequently by listening to the sound of the burst the operator ma
83. tion plus Noise to Distortion plus Noise for any defined multitone signal see also chapter MT SINAD p 30 Answer Bin Max integer see Equation 5 p 19 MT Sinad float NaN amp string measured MT SINAD result amp unit Default NaN not a number Unit dB Example Ao Measurement 1 MTSinad E 214 5 2235E 01 dB Explanation The returned MT SINAD value considers all signal components starting with the lowest possible frequency in the signal at the first bin 220Hz up to the highest frequency bin below 20kHz It calculates from the distortions and the signal components the single SINAD value If a band between two signal bins is too narrow to measure a distortion the error 246 is returned MEASurement 1 2 SELectiverss UNIT dBV V Use Defines the unit in which the RSS root sum square selective result shall be expressed Range dBViV string Default dBV Example B gt Meas1 Sel Unit dBV MEASurement 1 2 SELectiverss lt binstart gt lt binstop gt Use Returns the RSS value for the band from lt binstart gt to lt binstop gt including both levels NEUTRIK CORTEX INSTRUMENTS 56 71 V 3 32 RTM Parameter Range Units Default Example Explanation Multitone Audio Test System User Manual lt binstart gt lt binstop gt integer Bin Min to Bin Max Defined by MEASurement 1 2 SELectiverss UNIT dBVi V NaN not a number EH MEAS2 SEL 11 32
84. titone Audio Test System User Manual e e Se O de d DA ENT a li ath A OR HEN AI m allt il PW P T l TI l d iN ARA dt WEN Diir E 4i AAI i 1 Ee ll MME ENG Lae palio papado peana pone meso Die E EH Vic Win rns Pos qoaa Oestadosra Dir MIS TM Crestfactor 2 71 Io 0 005 0 01 0 015 0 02 0 025 to 0 005 0 01 0 015 0 02 0 025 Fig 14 Non Optimized Multitone Signal Fig 15 Optimized Multitone Signal Comparability of Multitone Measurements One has to be aware that the results of multitone testing cannot be compared directly with conventionally acquired results For instance distortion products may appear over the entire band due to the fact that each signal bin produces harmonics and intermodulates with other signal bins The strict separation between harmonic distortion and intermodulation cannot be guaranteed since at certain signal bins some intermodulation products and harmonic frequencies may fall together thus influencing the Distortion as well as the SINAD results However a multitone signal comes much closer to a real world signal than any single tone test signal The results are in qualitative terms comparable with conventional measurement results as long as the specific theory behind multitone testing is considered With a single tone stimulus the achieved results are directly comparable to conventional analyzers Please refer to the corresponding application note filed in the a
85. ual input dBm 20 log y 2 22dBm 20 log io impedance as e g 600Q y0 001 W R 2 V0 001 W SE dBmO dBm referred to or measured at a point of zero transmission level dBrn dB above reference noise Weighted circuit V 0 000025 V noise power in dB referred to 1pW E dBrn 20 log o OdBrn 20 108 o C We 600 O which is defined as OdBrn 90dBm JU W R 10 y 1W 6001Q Type of weighting is indicated by next letter see dBrnc dBrnc Weighted circuit noise power in dBrn measured on a line by measuring set with C message weighting aBrncO Noise measured in dBrnc referred to zero y ND transmission level point OTLP dBrnc0 dBrnc 20 logi cc ror NEUTRIK CORTEX INSTRUMENTS 68 71 V 3 32 RTM Advanced Multitone Audio Test System 6 SPECIFICATIONS Generator Number of channels Generator type Resolution Sampling rate Frequency resolution Number of signal memories Number of test signal frequencies Signal Frequencies Multitone burst duration Residual distortion Output Level Symmetric Level accuracy Flatness Analyzer Measurement functions Number of channels Resolution Sampling rate Residual distortion Frequency resolution Input Range bal Level accuracy Flatness Synchronization Measurement turn around time General Dimensions Weight Remote control Power requirements Calibration Operating temperature 2 multito
86. ural sound A multitone signal typically contains 2 to 31 signal frequencies each with a certain phase relation distributed over the frequency band of interest Obviously sophisticated test instruments are necessary to analyze all these signals with their interactions on each other Fig 9 and Fig 10 show a typical multitone signal in the time and frequency domain It is important to know that the waveform of the time plot strongly correlates with the phase relations between its single frequencies Since the max amplitude of the time signal directly determines the dynamic range of both the DUT and the analyzer a low peak value is both important and desirable NEUTRIK CORTEX INSTRUMENTS 16 71 V 3 32 RTM Multitone Audio Test System User Manual Amplitude 1 T I i B ES aia i i DOET TEE Amplitude dB 0 Ho o o S T Ss se I L l I I T l a o gt 0 2 DATT 0 617 77 BD edel I I l 1 l l l 0 0 002 0 004 0 006 0 008 0 01 Time ms Frequency kHz Fig 11 Time Plot of a Multitone Signal Fig 12 Spectrum of a Multitone Signal Obviously it is necessary to characterize the time signal by an appropriate value in order to
87. x 1706 19 992 kHz Table 5 Signal Parameter with Blocklength 4096 f 48kHz Blocklength 8192 Frequency spacing Af 5 859375 Hz Analyzer resolution 2 9296875 Hz Bin Min fmin 4 23 4 Hz Bin Max fmax 3413 19 998 kHz Table 6 Signal Parameter with Blocklength 8192 f 48kHz User Manual NEUTRIK CORTEX INSTRUMENTS V 3 32 21 71 RTM Multitone Audio Test System User Manual Generator amp 7 1 f comprises a completely independent two channel 16bit arbitrary generator The digital section has its own high level microprocessor enabling the system to react flexibly to external events communicate with various interfaces and reprogram the sample counter for the arbitrary generator Block Diagram 00000000 MEM 1 LED INDICATORS MEM 2 ARBITRARY LOGIC GPU IEEE 488 INTERFACE MEM 3 MEM 4 ISOLATION De a BD 18 BIT D A CONVERTER AMP gt LEE lt B 2 x IMPED 18 BIT D A CONVERTER gt AMP gt MUTE Fig 16 Block Diagram Generator Digital Section The CPU reads the samples out of a non volatile memory The memory block provides capacity for four independent test signals each with 16 bit resolution and any length defined in Table 1 Space is also provided for the header of each signal The master clock is derived from a high precision crysta
88. y be used after transmission of several multitone burst transmissions in mode EXT only The analyzer synchronizes itself onto the SYNC blocks of these preceding multitone bursts before it eventually gathers the burst in mode EXTnoheader Gathering Data After triggering and synchronization the analyzer waits one period of the multitone burst to let the transients of the DUT disappear before it starts with a two block FFT This calculation takes depending on the block length between 48ms and 190ms The analysis includes e Decoding of the bit stream to get two stereo signals e Windowing with Hanning window where necessary e Organization of bits bit reverse organization of results e Calculation of level and phase from the complex spectrum The calculated vector is placed in the result area of the memory and the DSP is ready for the next acquisition If the user queries for measurement results the CPU reads these stored data from the internal memory and computes the required results out of them This process requires considerable computations since all the bins have to be read squared and summed up for the results calculation As soon as this process is finished the results are transmitted and thus available for further processing NEUTRIK CORTEX INSTRUMENTS V 3 32 27 71 RTM Multitone Audio Test System User Manual Signal Analysis 8 Result Queries Level One core requirement of audio testing is the analysis of the frequency
89. y simply localize critical components and optimize their transmission behaviour The most frequent obstacle in the broadcast mode is the refusal of the analyzer to trigger to the incoming multitone burst This effect is usually caused by improper adjustments of the involved 47 generator analyzer or by sound enhancing instruments e g equalizer compressor limiter compander etc on the transmission line which modify the trigger signal in a way that it can t be recognized anymore Consequently the efforts to overcome missing triggerings have to focus on the proper adjustment of the sending and the receiving 47 as well as on the mutual optimization between the trigger signal and the sound enhancing systems Possible Cause Effect Suggested Solution NEUTRIK CORTEX INSTRUMENTS V 3 32 37 71 RTM Generator output level too low and or Analyzer input range too high Generator output level too high Analyzer input range too low Very strong sound enhancing effects or a low quality of the transmission line Multitone signal not identical on generator amp analyzer Multitone Audio Test System The incoming trigger signal level doesn t match vs the analyzer sensitivity so that the trigger can t be recognized The trigger signal is modified by sound enhancing units in a way that it can t be recognized any more by the analyzer The input stage of the analyzer is too sensitive i e overl
90. y to do further repairs Call your local dealer for support Interface This LED indicator lights up if the IEEE interface is busy and receives a command It remains illuminated until the user has read the answer from the interface In standby mode with no activity on the IEEE interface the LED is off Calculating Whenever FFT or filtering calculations are performed this LED lights up Trigger This LED indicator goes on as soon as a amp 7 7 trigger has been successfully detected and remains lit until the user has read the result s from the buffer Overload Should the input signal overload one or both channels the LED indicator goes on This happens if the maximum input voltage of 20dBu 10V is exceeded or if a higher voltage than the selected range is applied In such a case the error LED also lights up The overload LED resets with the next measurement and the ranges set correctly Error X7 1M handles an error queue internally Whenever an error is detected hardware or software the error LED comes on It disappears as soon as the error number has been queried through the IEEE interface NEUTRIK CORTEX INSTRUMENTS 14 71 V332 RTM Multitone Audio Test System User Manual Test of Function After connection of the cables and proper setting of the IEEE address it is recommended to run the subsequent short program to confirm the proper function of the system 47 14 can be operated with any operating system providing an I
91. zer input range e USER this parameter allows to define the trigger condition according to user specific demands However since this application requires a very thorough and detailed understanding of the whole triggering complex this approach is for very advanced users only who have a profound understanding of all possibilities and their consequences ATTENTION Improper configuration of the USER trigger may result in a always or never condition where the analyzer triggers on almost every incoming signal music speech etc or never recognizes any trigger even if itis a correct one The trigger signal of a 47 multitone burst comprises three signal bins at different frequencies and with individual levels In order to avoid false triggerings the receiving 7 permanently monitors the input signal on strictly this pattern Furthermore the analyzer checks whether two more predefined signal bins are empty i e whether no level can be detected at these two Amplitude dB frequencies If this is the case the analyzer recognizes the incoming signal as a 7 multitone burst and triggers to it 0dB Fig 24 visualizes the characteristic of a 27 11 triggersignal The bottom bars T at the fre quencies 1 3 and 5 rep resent the set signal bins and their amplitudes de 1 2 3 4 5 fined against the ground level of the generator whereby signal bin 1 and 5 have identical amplitudes The frequencies 2

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