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1. pue Oye TPS 9 pue 9 pue Oye TPS 9 3481 u spu 159481 99 0 do Qou nb uj 799607 s lnpotu 97 pue 91 6 pue 9 d S 9110 92 001 31 2 ON 133HS OL 000 1 000 1 61 60 10 31906 ava SI A 1 095 9969 A d Q 0 d91 xSV 97880 5 SAV 002 CAaLVHOdHOONI 15 1 p 996 SE Jndpno Jo dyno 35982. OPERATION OF THE GENERATOR CONTROLLER 20 RF GENERATOR MODULES 20 2542 MODULATION GENERATOR 21 ee ta C AFS 12WB FILTER SELECTORS 21 2 6 2 yata a Gak a Qua ad OPERATION OF AFS 12WB MICROCONTROLLER 21 SECTION III REPAIRS TO THE EQUIPMENT 22 wakap ea INTRODUCTION 22 scan ae ete REPAIRS TO THE GENERATOR MODULES 22 aa SW evades aes REPAIRS TO THE AFS 12WB 22 a MISCELLANEOUS REPAIRS 23 SECTION SPECIAL DTS DISTORTION MEASUREMENTS 24 elated ihe INTRODUCTION 24 dam Rie We FLOW CHARTS 24 SECTION V DIAGRANS l 30 SECTION I OPERATING INFORMATION 1 1 Introduction The Model ASX 16C D or the ASX 16C D portion of the DTS typically contains a bank of Generator Modules with attached filters a Modulation Generator one or more sets of programmable RF attenuators typically 0 dB to 81 dB and a set of coaxial RF relays The bl
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4. SET AMPLITUDE REFERENCE 60 dBm THIS IS A CHANGE IN LEVEL OF 50 dB RL 60 DBM SET S R S S A INPUT RANGE 20 dBV IRNG 20 IF THIS CREATES AN OVERLOAD ADJUST INPUT RANGE WAIT 1 SECOND FOR SETTLING USE A SUBROUTINE READ Y VALUE OF S R S S A MARKER SAVE THE dBV VALUE AS CALCULATE THE DISTORTION CSB IN dB 50 Y3 Y2 DY1 2 X MOD SETUP SET ASX 16C D TO OBTAIN THE DESIRED OUTPUT LEVEL FROM DUT USE ALEVELLING SUBROUTINE SET ASX 16C D TO QOFF MODE QOFF SET UP ASX 16C D DTS RELAYS TO ROUTE SIGNAL AS FOLLOWS FROM OUTPUT OF DUT TO AFS 12WB TO HP S A RUDDUUDDUUX 27 SET UP HP S A REF ATTENUATOR MANUAL 0 dB AT MAN ATO DB AMPLITUDE REFERENCE 10 dBm RL 10 DM SET CENTER FREQUENCY TO MEASUREMENT FREQUENCY EXAMPLE 499 25 MHZ CF 499 25 MHZ SET SPAN 0 Hz SPO HZ RESOLUTION BANDWIDTH MANUAL 30 KHz RB MAN RB 30 KHZ VIDEO BANDWIDTH MANUAL 30 KHz VB MAN VB 30 KHZ SET ASX 16C D FOR 15 75 KHz MODULATION MODNORM MODULATE ALL ASX 16C D CARRIERS 140 TURN OFF ANY UNUSED ASX 16C D CARRIERS USE A SUBROUTINE SET UP S R S S A TURN OFF AUTOMATIC LIMIT TESTING TSTS 0 SELECT INPUT SOURCE A ISRC 0 SET GROUND FLOAT COUPLING AC IGND 0 ICPL0 SET INPUT RANGE AT 0 dBV IRNG 0 IF THIS CREATES AN OVERLOAD ADJUST INPUT RANGE SET TOP REFERENCE 10
5. fly LOL TEST EQUIPMENT INCORPORATED ASX 16C D AFS 12WB DTS OPERATING MANUAL ver 1 2 MODELS ASX 16C D AFS 12WB AND DTS OPERATING MANUAL SECTION OPERATING INFORMATIONN 3 Tenunan ah ch ay INTRODUCTION 3 FEATURES OF THE 16 3 m u uW a SOFTWARE INTERFACE FOR THE ASX 16C D 3 ASX 16C D COMMANDS 4 kapa aa MANUAL OPERATION OF MODEL AFS 12WB 12 REMOTE CONTROL OF MODEL AFS 12WB 12 Cay qawa misi ba a nts AFS 12WB COMMANDS 13 eg za asqa ea anal nate TYPICAL SOFTWARE FOR THE MODEL AFS 12WB 13 tet ea trie ghee ADJUSTING THE OUTPUT LEVELS OF THE 16 13 ayama PERFORMING TESTS WITHOUT USING ALL CARRIERS 14 CALIBRATING THE ASX 16C D BASE LEVELS 15 het ADJUSTING ASX 16C D OSCILLATOR FREQUENCIES 17 aaa sa FREQUENCY ADJUSTMENT PROCEDURE 18 SECTION THEORY OF OPERATION 20 INTRODUCTION 20
6. change value is set to 0 zero the frequency adjustment is returned to its middle step step 2048 Negative change values move the carrier lower in frequency unsigned change values move the carrier higher in frequency See Section 1 4 for details If the module value is set to 0 zero the requested change is performed on all available modules Normally such a command would make no sense however a special case exists when the change value is 0 When both module and change are zero the adjustments of all carrier frequencies are returned to their middle steps step 2048 this is the proper starting point if the frequency adjustments ever become scrambled Because the FRmodule change command performs no error checking it is possible for you to create a wrap around situation This occurs when you move an adjustment above step 4095 or below step zero In wrap around the next step above 4095 is step 0 and the next step below step 0 is 4095 To avoid this problem use the FRVA command before attempting to adjust the frequency of any module The general form of the FRVA command is FRVAmodule where module specifies the module whose step level value is to be read Examples FRVA1 FRVA122 The FRVA command is a handshake command which requests the current setting of the specified module s frequency adjustment The response from the ASX 16C D is the current step from 0 to 4095 The ASX16C always returns a four di
7. If there is a break in any of the coaxial cabling which is daisy chained from module to module all modules following the break will exhibit the same bad characteristics Another cause of no output or intermittent output is a stalled or intermittently stalling oscillator If the malfunction still exists after checking for bad connections and for a stalled oscillator the module will have to be removed from the ASX 16C D After opening the module s case look for any obvious signs of damage such as a charred component or a broken connection Although repairs can sometimes be made by the customer it is advised that any malfunctioning modules be returned to Matrix Test Equipment for repairs You can usually rearrange the cabling to jump over the defective module thus keeping the rest of the system operating until the defective module can be repaired 3 3 Repairs to the AFS 12WB Before assuming that there is a problem with the AFS 12WB first use a spectrum analyzer to be sure that there is a strong carrier present at the suspected filter s frequency A failure in the AFS 12WB could be caused by a bad filter or by a failure in the filter selection circuitry To establish where the problem is located temporarily swap the coaxial connections of the suspected filter with one of the working filters The suspected filter will now be accessed using the working filter s access address and the working filter will be accessed using the suspected filte
8. Polarity Reversing Relay for Unit Under Test s DC Power The AFS 12WB portion of the DTS C handles the AReceiver Filter Selection 2 2 Operation of the Generator Controller On power up or reset the Generator Controller sets parts of the ASX 16C D to known protected states When the unit is first turned on the DC power supply to the Generator modules is turned off This is to protect any external equipment such as a power meter sensor from a sudden surge of RF power which might otherwise occur on power up After the Generator Controller has gone through its start up procedure leaving its peripherals in a safe condition the Generator Controller turns on the DC supply to the modules If the Generator Controller is reset manually without turning its power off the DC power supply is unaffected and remains on On reset the ASX 16C D s RF attenuators are automatically set to their highest level of attenuation If the ASX 16C D is part of a Model DTS the Generator Controller briefly exercises the RF coaxial relays in the switch test fixture resulting in a dstiinctive series of audible clunks from the switch test fixture This can reduce contamination problems caused by relay contacts which never change position Unless a new unprogrammed RAM has just been installed in the Generator Controller neither the Base Levels nor module levels are affected by a reset or power up The ASX 16C D is equipped with a battery backed up RAM allow
9. automatically set to their middle settings on reset or power up Sets the FREQUENCY ADJUST flag in the ASX 16C D s battery backed up RAM When this flag is set commands to adjust the module s frequencies are ignored If this flag is set the module s frequency settings are unaffected by resets Requests the status of the Frequencies Done flag If the flag has been set using the FD command the response from the ASX 16C D is S If the flag is cleared the response is C Adjusts the specified module s carrier frequency The maximum change for each FRmodule command is limited to a range of or 255 steps however the FRmodule command can be sent several times to the ASX 16C D if it is desired to move in steps greater than 255 The total range of adjustment covers 4096 steps To return a carrier to its center frequency send a change value of 0 zero To set all carrier to their center frequencies use the command FRO 0 Negative values move the carrier down in frequency unsigned values move the carrier up in frequency See Section 1 3 for details Resets do not affect the frequency settings This command will be ignored if the FREQUENCY ADJUST flag is set see above Note that the comma must be sent NOTE The FRmodule command is a SLAVE command No checking is performed to see if the FRmodule command will cause the ASX 16C D to exceed the maximum or minimum steps Use the FRVA command below before changing the frequen
10. in dB in 1 dB steps SLAVE 20 over a range of 0 to 81 dB In units with the 0 5 dB option the data can have a value 11 of 0 to 82 5 in 0 5 dB steps In units with more than one bank of RF Attenuators this command sets all available banks to the data value When the unit is reset all RF attenuators are set to the maximum value AAdata Sets only the ASX 16 s A RF Attenuator to the value of the data specified in the SLAVE AA20 optional command see Adata command for details The other RF attenuators are not 11 changed by this command This command is only used in units with more than one bank of RF attenuators ABdata Sets only the ASX 16 s B RF Attenuator to the value of the data specified in the SLAVE AB20 optional command see Adata command for details The other RF attenuators are not AB11 changed by this command This command is only used in units with more than one bank of RF attenuators ACdata Sets only the ASX 16 s C RF Attenuator to the value of the data specified in the SLAVE AC20 optional command see Adata command for details The other RF attenuators are not AC11 changed by this command This command is only used in units with more than one bank of RF attenuators AV In units with one bank of RF attenuators requests the Value of the ASX 16 s RF HANDSHAKE AV Attenuator setting For standard units the response from the ASX 16 is a three digit number with leading zeros as necessary from 000 to
11. in the command These two are set to SLAVE 28 37 module CW unmodulated operation The S command is used for setting up the ASX 16C D 2 112 for a Second Order distortion test The Frequency Synthesizer used to generate the frequency offset carrier is set up separately Note that the comma must be sent SMmodule Requests the operating mode of the specified Module Response from the ASX 16C D HANDSHAKE SM1 optional is always a three character string For CW unmodulated operation the response is 5 100 CW including one blank space For modulated operation the response is MOD For power off non operation the response is OFF For power low 35 dB down or more the response is LOW SRC Sets the optional SOURCE GENERATOR coaxial relays to the SOURCE Head end SLAVE SRC optional position The SYSTEM output will contain only the Head end signals Tmodule Turns off all modules except the three modules specified in the command These SLAVE S6 8 9 module three are set to CW unmodulated operation The T command is used for setting up 52 41 42 module the ASX 16C D for a discrete Third Order distortion test The Frequency Synthesizer used to generate the frequency offset carrier is set up separately Note that the comma must be sent 10 SIGNAL V I data Xmodule MEANING In units with one RF attenuator bank Varies the RF Attenuator by the amount in dB specified by the data The
12. module s to the specified level using the low resolution mode The level can be any integer value from 0 to 180 If a module of 0 zero is specified all modules are set to the specified level Although this command alters the module s level stored in RAM it does not affect the output carrier amplitudes until the module is next leveled The Fmodule level command has been replaced by the FHmodule level command but the older command is retained for compatibility with older user written software See the L commands below for more information on adjusting the level of a module Note that the comma must be sent Sets specified module s to the specified level using the high resolution mode The level can be any value from 0 to 720 If a module of 0 zero is specified all modules are set to the specified level This command provide four times the resolution of the older Fmodule level command Although this command alters the module s level stored in RAM it does not affect the output carrier amplitudes until the module is next leveled See the L commands below for more information on adjusting the level of a module Note that the comma must be sent Clears the FREQUENCY ADJUST flag in the ASX 16C D s battery backed up RAM Only when this flag is cleared can the carrier frequencies be adjusted If this flag is still cleared when the unit is reset or the power is turned off the Frequency adjustments of all channels will be
13. move by that number of steps When a module s level is changed its carrier is automatically turned on CW When the specified module number is 0 zero indicating all modules if any module cannot be stepped by the requested amount an N response is generated and no levels are changed Requests the step Level of the specified Module in the low resolution mode Response from the ASX 16C D is a 3 digit number with leading zeros as necessary from 000 to 180 This command has been replaced by the LMHmodule command but has been retained to maintain compatibility with older user written software Requests the step Level of the specified Module in the high resolution mode Response from the ASX 16C D is a 4 digit number always with a leading zero from 0000 to 0720 TYPE SLAVE SLAVE HANDSHAKE HANDSHAKE HANDSHAKE HANDSHAKE HANDSHAKE 112 15 112 15 10 75 10 75 LH12 60 LH12 60 1 0 300 1 300 LM1 LM100 LMH1 LMH100 SIGNAL Mmodule NON optional NOFF optional NORMAL OUTCRLF OUTCR Pmodule QLOW QOFF MEANING Applies power to the specified module and sets the module for 100 Modulated operation If the module number is O zero all modules are set for 100 Modulated operation In a Model DTS applies power to the Noise Source NOTE The NON and NOFF commands affect only the power to the Noise Source The R command see below must be used to switch the Noise S
14. the response is C Sets the Base Level flag in the ASX 16C D s battery optional backed up RAM When this flag is set commands to adjust the Base Levels Bmodule level are ignored When this flag is set the Base Levels are unaffected by resets and power up Requests the low resolution Value of the specified module s Base Level The response from the ASX 16C D is a 3 digit number with leading zeros if necessary from 000 to 075 This command has been replaced by the BVHmodule command but the older command has been retained for compatibility with user written software NOTE See Section 1 9 for information about customer calibration of the ASX 16C D module Base Levels PE HANDSHAKE SLAVE SLAVE SLAVE HANDSHAKE SLAVE HANDSHAKE AVC BH1 212 0 300 BD BF BS BV1 BV122 SIGNAL BVHmodule Cmodule Fmodule level FHmodule level FC FD FF FRmodule change MEANING Requests the high resolution Value of the specified module s Base Level The response from the ASX 16C D is a 4 digit number always with a leading zero from 0000 to 0300 BYPASS causes the RF filter bank to be SLAVE BYPASS bypassed by a set of RF relays Applies power to the specified module and sets the module for CW unmodulated operation If the module number is 0 zero all modules are set for CW operation the normal arrangement of carriers for a Composite Triple Beat Test Sets specified
15. there is still sufficient room for the required adjustment 12 Assuming there is adequate adjustment range remaining move the frequency up or down by the number of steps calculated in step 10 above using the FR command Use an unsigned value to increase the frequency or a negative value to decrease the frequency For example if we wish to move module 1 down in frequency by 254 steps use FR1 254 18 13 14 15 16 If you need to move in steps greater than 255 use multiple instructions For example to move module 1 down by 310 steps send the following two commands each command must be sent separately FR1 255 amp FR1 55 Re check the frequency If additional adjustment is necessary go back to step 10 Repeat Steps 4 through 13 for each module After all channels have been adjusted turn off the carriers of all modules using the command P0 For Model DTS only return the GF relay to its OUT position using the command GFOUT 19 SECTION II Theory of Operation 2 1 Introduction The theory of operation of the Model ASX 16C D and Model AFS 12WB are covered separately The DTS C includes both of these devices In the DTS C the ASX 16C D portion controls the following some of these features may be omitted from your DTS C Generator Modules All 1 dB and 10 dB RF Step Attenuators All RF amplifiers and Coaxial Relays GA GB Coaxial Relay GFIN GFOUT Coaxial Relay DC Power to an optional Noise Source
16. to Step Level 480 The Base Level of the middle module has been reduced by 80 steps reducing its output power by 2 dB the right hand module s Base Level has been reduced by 160 steps reducing its output power by 4 dB Because the modules vary somewhat in their linearity dB per Step there will be some variation in the amount of level change obtained from the L command see Section 1 4 Below is a procedure for updating the ASX16C D s Base Level calibration Normally Base Level calibration is performed only at the Matrix Test Equipment factory prior to shipping If periodic readjustment of the Base Levels is desired or if additional modules are added to the ASX16C by the customer or if the Base Level information is lost to due equipment failure the provided procedure will allow you to re establish proper Base Levels Certain equipment is required to perform this calibration Model ASX 16C D or Model DTS power meter with a minimum of 0 1 dB resolution host computer with IEEE 488 bus interface and software Note that Step 2 calls for a setting of 10 dB of RF attenuation This is to protect the power meter from possible overloading If your power meter does not need this protection delete this step Consult Section 1 3 for information on using the ASX 16C D remote control commands 15 11 12 13 14 15 16 17 Reset the ASX 16C D by using the front panel RESET button Allow the ASX 16C D to warm up for at leas
17. 081 For units with the 0 5 dB option the response from the ASX 16 is a three digit number followed by either 0 or 5 with leading zeros as necessary from 000 0 to 082 5 the extra digit allows for future use of attenuators whose maximum value may exceed 99 dB In units with multiple attenuator banks use the AVA AVB or AVC commands instead of the AV command SIGNAL AVa optional BHmodule level BC BD BF BS BVmodule MEANING In units with more than one RF Attenuator bank requests the Value of the ASX 16 s RF Attenuator specified by a For standard units the response from the ASX 16 is a three digit number with leading zeros as necessary from 000 to 081 For units with the 0 5 dB option the response from the the ASX 16 is a three digit number followed by either 0 or 5 with leading zeros as necessary from 000 0 to 082 5 the extra digit allows for future use of attenuators those maximum value may exceed 99 dB This command is only used in units with more than one bank of RF attenuators Sets the specified module s Base Level using the high resolution mode whose range is 0 to 300 Do not use this command until you have received proper training from Matrix Test Equipment This command replaces offers the older Bmodule level command It offers four times the resolution of the Bmodule level See the Lmodule commands below for information on adjusting the level of a module When a m
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20. ASX 16 responds with an N if the attenuator cannot bevaried by the requested amount or with a G if the attenuator can be varied by the requested amount In units with multiple RF attenuator banks use the VA data VB data or VC data command In units with more than one RF Attenuator bank Varies optional the RF Attenuator specified by a by the amount in dB specified by the data The ASX 16C D responds with an N if the A attenuator cannot be varied by the requested amount or with a G if the attenuator can be varied by the requested amount The B and C Attenuators are unaffected by this command This command is only used in units with more than one bank of RF attenuators Turns on all modules in the 100 modulated mode except for the specified module which is instead set for CW unmodulated operation The X command is used for making X mod Cross modulation tests 11 PE HANDSHAKE HANDSHAKE SLAVE V12 V 12 VA12 VA 12 VB12 VB 12 VC12 VC 12 X1 X13 X101 1 5 Manual Operation of Model AFS 12WB Manual operation of the AFS 12WB is quite simple The narrow band and wide band models function identically Each filter can be selected by entering its three digit identification number on the front panel keyboard The three digit display will indicate the entry as each key is pressed Even if your unit has fewer than one hundred filters a three digit entry must still be used For example to select filter num
21. NT EXAMPLE CHANNEL 76 P76 SET HP S A ATTENUATOR TO 0 dB SET AMPLITUDE REFERENCE 60 dBm THIS IS A CHANGE IN LEVEL OF 50 dB RL 60 DBM SET S R S S A INPUT RANGE 20 dBV IRNG 20 IF THIS CREATES AN OVERLOAD ADJUST INPUT RANGE WAIT 1 SECOND FOR SETTLING USE A SUBROUTINE READ Y VALUE OF S R S S A MARKER SAVE THE dBV VALUE CALCULATE THE DISTORTION CTB IN dB 50 Y2 Y1 2 CSB CONTINUED RE TUNE S R S S A TO 1 KHz CTRF 1000 TURN OFF ASX 16C D CARRIER WHOSE CHANNEL IS USED FOR CSB MEASUREMENT EXAMPLE CHANNEL 76 499 25 MHZ P76 SET SYNTHESIZER TO CARRIER FREQUENCY JUST TURNED OFF EXAMPLE 499 25 MHZ FR 499 25 MZ SELECT INTERNAL AM MODULATION 1 KHz AND 99 26 AMS3 AM 99 PC ADJUST SYNTHESIZER AMPLITUDE UNTIL READING ON S R S S A IS WITHIN 5 db OF Y1 USE A SUBROUTINE ALLOW 1 SECOND BEFORE EACH READING RECORD THE DIFFERENCE BETWEEN Y1 AND THE CURRENT Y VALUE AS DY1 SET SYNTHESIZER TO CSB MEASUREMENT FREQUENCY EXAMPLE 500 50 MHZ 500 50 1 2 SET HP S A CENTER FREQUENCY TO CSB MEASUREMENT FREQUENCY CF 500 50 MHZ RE TUNE S R S S A TO 1 12 KHz 1120 READ Y VALUE OF S R S S A MARKER SAVE dBV READING TURN OFF SYNTHESIZER OUTPUT AP 127 DB CSB CONCLUDED SET HP S A ATTENUATOR TO 0 dB
22. UT LEVEL FROM DUT USE ALEVELLING SUBROUTINE SET ASX 16C D TO QOFF MODE QOFF SET UP ASX 16C D DTS RELAYS TO ROUTE SIGNAL AS FOLLOWS FROM OUTPUT OF DUT TO AFS 12WB TO HP S A RUDDUUDDUUX SET UP HP S A REF ATTENUATOR MANUAL 10 dB AT MAN AT 10 DB AMPLITUDE REFERENCE 10 dBm RL 10 SET CENTER FREQUENCY TO MEASUREMENT FREQUENCY EXAMPLE 499 25 MHZ CF 499 25 MHZ SET SPAN 0 Hz 5 2 RESOLUTION BANDWIDTH MANUAL 30 KHz RB MAN RB 30 KHZ VIDEO BANDWIDTH MANUAL 30 KHz VB MAN VB 30 KHZ SET ASX 16C D TO 1 12 KHz MODULATION MODE MOD1KHZ MODULATE ALL ASX 16C D CARRIERS 140 TURN OFF ANY UNUSED ASX 16C D CARRIERS USE A SUBROUTINE SET UP S R S S A TURN OFF AUTOMATIC LIMIT TESTING 8750 SELECT INPUT SOURCE A ISRC 0 SET GROUND FLOAT COUPLING AC IGND 0 ICPL0 SET INPUT RANGE AT 0 dBV IRNG 0 THIS CREATES AN OVERLOAD ADJUST INPUT RANGE SET TOP REFERENCE 10 dBV TREF 0 10 SET SPAN 390 Hz SPAN 11 25 TURN MARKER ON CENTERED MRKR 0 1 MRCN SET CENTER FREQUENCY TO 1 12 KHz CTRF 1120 BEGIN DISTORTION MEASUREMENT WAIT 1 SECOND FOR SETTLING USE A SUBROUTINE READ Y VALUE OF S R S S A MARKER SAVE THE dBV VALUE 1 CONTINUED ORGOTO CSB CONTINUED CTB CONTINUED TURN OFF ASX 16C D CARRIER WHOSE CHANNEL IS USED FOR CTB MEASUREME
23. VA command For example for module 1 use FRVA1 This is a handshake command Make sure you read the response If you need to move up in value but the response was 4095 or if you need to move down in value but the response was 0000 you have reached the adjustment limit In this case either the module needs a new crystal or something is wrong with your measuring procedure or with your frequency counter 9 Assuming there is adequate adjustment range remaining move the frequency up or down 100 steps using the FR command Move the step level up to increase the frequency move the step level down to decrease the frequency For example to move module 1 up 100 steps use the command FR1 100 Use the frequency counter to read and record the module s new frequency F2 If it is now within acceptable limits move on to the next module starting with step 4 above If additional adjustment is needed calculate the steps Hertz ratio for this module using the following formula steps Hertz 100 F1 F2 10 Now multiply the remaining frequency error by the steps Hertz ratio to determine approximately how many additional steps of adjustment are required For example if FO is the desired frequency the approximate amount of change required is change F2 X steps Hertz 11 If the previous value returned by the FRVA command indicated the module was close to the end of its adjustment use the FRVA command again to make sure
24. X 16C D This feature is used when making Composite Second Order Beat and Discrete Second and Third Order tests The DTS C is typically equipped with a set of RF coaxial relays which are used to reconfigure the RF path of the signals allowing the routing to or the bypassing of most of the included equipment 1 3 Software Interface for the ASX 16C D There are two types of commands which can be sent to the ASX 16C D SLAVE commands and HANDSHAKE commands All valid SLAVE commands are executed as soon as they are received The HANDSHAKE commands utilize and require two way communications In practice the host computer IEEE 488 system controller sends a HANDSHAKE command to the ASX 16C D then the host computer reads the ASX 16C D s response This software handshake must be completed by reading the ASX 16C D s response If the ASX 16C D s response is not read the ASX 16C D s interface to the IEEE488 bus will be locked up until it is completed Any spaces in received commands are ignored Commands to the ASX 16C D AFS 12WB can contain either UPPER CASE or lower case letters Commands to the ASX 16C D AFS 12WB can be terminated with either a carriagereturn line feed ASCII code 13 followed by ASCII code 10 or with just a line feed character Responses from the ASX 16C D will be terminated with a carriage return only power up or after a reset If the host computer customer s equipment requires a carriagereturn linefeed termin
25. ation the output character sequence from the ASX 16C D can be changed by using the OUTCRLF command The OUTCRLF and OUTCR commands are described in this Section for the ASX 16C D Whenever appears in the chart below it indicates that an unsigned number will be assumed to be positive and a number preceded by a sign will be taken as negative Do not include a in front of numerical data which is supposed to be positive For example negative 12 is sent as 12 positive 12 is sent as 12 When a module number is indicated in the following command chart the module number should be an integer from 1 to N where N is the highest module number in your system N has a maximum value of 255 If a module number of 0 zero is used on commands where such a value is permitted the command is applied simultaneously to all modules in the ASX 16C D The Channel Designation Sheet provided with the unit indicates the relationship between module number and the generated received frequency of the module The chart starting on the next page lists the commands available in the ASX 16C D portion of the DTS C Some commands may be unavailable in your equipment Commands which are optional or which require additional equipment are marked optional Command literals are indicated in UPPER CASE variables are indicated in lower case 1 4 ASX 16C D COMMANDS SIGNAL MEANING TYPE EX Adata Sets the ASX 16C D s RF Attenuator to the value of the data
26. ber 1 press 001 on the keypad The keyboard can also be used to scan to the next or previous filter by using the Scan Up or Scan Down key respectively Note that scanning may extend beyond the actual number of filters in your unit This feature allows additional filters to be added by you at a later time If you need to RESET the AFS 12WB due to a malfunction manual reset can be accomplished by simultaneously pressing the Scan Up and Scan Down keys The Model AFS 12WB can be in either the Local or Remote mode In the Model AFS 12WB the front panel s LOCAL and REMOTE lights will indicate that the most recent filter selection was received from either the keypad or from the IEEE488 bus respectively Configuration Mode 3 3 For models with Attenuators and or the PA 2020 Pre Post Amplifier installed a special Configuration Mode can be activated to manually control these options Entering O00 on the keypad will activate the configuration mode Once in this mode you can Scan Up or Scan Down to cycle through the Attenuator settings in 5dB increments 0 80dB The list below shows the commands for the PA 2020 200 Sets PA 2020 to PA1IN Preamp 1 Only 300 Sets PA 2020 to Preamp 1 Only 400 Sets PA 2020 to PA2IN Preamp 2 Only 500 Sets 2020 to PAZOUT Preamp 2 Only 600 Sets PA 2020 to PAIN Preamps 1 amp 2 Only 700 Sets PA 2020 to PAOUT Preamps 1 amp 2 If you enter configurat
27. cy of a module PE HANDSHAKE SLAVE SLAVE SLAVE SLAVE SLAVE HANDSHAKE SLAVE BVH1 BVH122 C1 C100 1 63 F67 70 F0 75 F0 180 FH1 252 FH67 280 FH0 300 FH0 720 FC FD FF FR2 250 FR4 12 FR45 0 FR0 0 SIGNAL FRVAmodule FRVmodule FS GEN optional GFIN optional GFOUT optional HH HL MEANING Requests the current Value of the specified module s frequency adjustment setting The value sent by the ASX 16C D is a four digit number with leading zeros if necessary from 0 to 4095 This command replaces the older FRV command see below NOTE To determine if there is adjustment room left in a given module use the FRVA command to obtain its step value To avoid frequency setting errors make sure the commands sent to the ASX 16C D never cause a frequency adjustment to move above 4095 or to drop below 0 Requests the current Value of the specified module s frequency adjustment setting This command has been replaced by the FRVA command but has been retained to insure compatibility with previously written software The step value sent by the ASX 16C D is the actual step from 0 to 4095 divided By 16 This reduces the data to a number between 0 and 255 The response from the ASX 16C D is a 3 digit number with leading zeros if necessary from 000 to 255 NOTE To use the FRV command to determine if there is sufficient adjustment room left in a giv
28. dBV TREF 0 10 SET SPAN 390 Hz SPAN 11 TURN MARKER ON CENTERED 0 1 MRCN SET CENTER FREQUENCY TO 15 75 KHz CTRF 15750 BEGIN DISTORTION MEASUREMENT WAIT 1 SECOND FOR SETTLING USE A SUBROUTINE READ Y VALUE OF S R S S A MARKER 28 SAVE THE dBV VALUE Y1 J TURN OFF ASX 16C D CARRIER WHOSE CHANNEL IS USED FOR CTB MEASUREMENT EXAMPLE CHANNEL 76 P76 WAIT 1 SECOND FOR SETTLING USE A SUBROUTINE READ Y VALUE OF S R S S A MARKER SAVE THE dBV VALUE X MOD IN dB Y2 Y1 29 SECTION V DIAGRAMS 30 wo x AG 0210232514 ON 1205 O h 000 1 000 1 21 60 10 31 98 Ag 0190 3 d q O g9 XSV 97880 XISTIAAIN SAV 002 15 1 5 887 9149 dL ONA 981 61 09 1241100 seg sued OT 340 1 29 ZUM SL ST pog ALVI TA 5099 aP 020 sdayg APOT 02020 Ta 06
29. ed power meter reading 510 E R D Convert E to steps 025 dB per step by multiplying the error by 40 520 E 40 E Note due to errors in linearity some modules may produce steps greater than 025 dB If you run into this problem multiply by 20 instead of 40 in line 520 5 Correct the level of module M and read the ASX 16C D s response by using the following commands 600 OUTPUT 724 LH 610 ENTER 724 USING A R 620 IF R N THEN GOTO 2000 Lines 2000 through 2020 handle modules which have run out of adjustment range 2000 PRINT ERROR 2010 PRINT MODULE NUMBER 15 AT ITS LIMIT 2020 STOP 6 When the amplitude of this module is correct repeat Steps 2 through 5 for each of the remaining modules If the carrier levels are to be sloped the value of D in Step 4 will change for each module If the desired level cannot be obtained because the measured level alternated between being too great or too small as the level is moved up or down by a single step follow the directions in the Note in Step 4 1 10 Performing Tests Without Using All Carriers It is often desirable to make distortion measurements using a limited number of carriers For example the ASX 16C D might be outfitted with seventy six channels but the desired X mod test is to be performed using only channels 2 through W The carriers below channel 2 module number 8 in this example and those above W module 42 must be turned off In this
30. en module multiply the step value obtained by 16 This gives the approximate step setting which is a number in the range of 0 to 4095 Note that a range of 16 steps will return the same response For example steps 1600 through 1615 will return a value of 100 For this reason using the new FRVA command is preferred Sets the FREQUENCY ADJUST flag in the ASX 16C D s optional battery backed up RAM When this is set commands to adjust the modules frequencies are ignored If this flag is set the module s frequency settings are unaffected by resets Sets the optional SOURCE GENERATOR coaxial relays to the GENERATOR ASX 16 position The SYSTEM output will contain only the ASX 16 signals Switches frequency counter into RF path NOTE Due to strong signals generated by the frequency counter which can interfere with other equipment the frequency counter must be switched OUT except when frequency measurements are made Switches the frequency counter out of the RF path Halts the Modulation Generator in its High state This causes all modules which are set for 100 modulation to drop their carrier levels by a minimum of 35 dB and to enter a CW unmodulated mode All modules which are set for CW operation will function normally Under certain circumstances this feature can save programming steps when it is necessary to frequently switch the modules operating modes Halts the Modulation Generator in its Low state This ca
31. example the undesired carriers are generated by modules 1 through 7 and modules 43 through 76 160 OUTPUT 724 A35 170 OUTPUT 724 X8 171 FORI 1TO7 172 OUTPUT 724 173 NEXTI 174 lt 43 76 175 OUTPUT 724 176 180 OUTPUT 723 X8 190 ENTER 723 USING R D ETC 14 Line 170 turns on all modules 100 modulated except for module 8 which is turned on CW Lines 171 through 173 and lines 174 through 176 turn off the two groups of undesired carriers 1 11 Calibrating the ASX 16C D Base Levels Each ASX 16C D generator module is individually adjustable over an approximately 25 5 dB range This 25 5 dB range is associated with 255 Step Levels of about 1 10 dB for each Step Level in the low resolution mode and 1020 steps of 025 dB in the high resolution mode The linearity error over any 5 dB range of adjustment is approximately plus or minus 0 24 dB Due to differences in operating frequencies and therefore in output stages and output filters the modules maximum output levels vary over a wide range As explained below and in Figure 2 the Base Level setting is used to compensate for these differences allowing all modules to have nearly identical output levels and ranges of adjustment To insure that all modules can be set to the same output power levels the maximum output power is lowered for the strongest highest output power modules This is accomplished by reduci
32. f you ordered the multiple relay bank option for your unit you can address up to four banks of eight relays a total of 32 relays To address a bank 1 through 4 place that bank s number immediately after the R in the command For example to control Bank 2 use a command similar to R2UVUUUDDDD If you leave out the Bank number the command will be applied to Bank 1 Example shown uses eight relays If your unit has more than eight relays ion one bank the additional data should be placed after the eight character of the data Example for ten relays RUDDUXDDUUU The following example probably does not agree with the equipment in your unit but demonstrates the kind of cautions to look into to avoid equipment damage Example RDUXDUUDU connects the combined ASX 16 and or Frequency Synthesizer outputs to the input of the device under test The output of the device under test is connected to the input of the AFS 12WB filter bank The output of the filter bank is routed to the input of the Network Analyzer To protect the RF Power Meter from accidental overload or static electricity one of the relays is used to connect its RF input to its own Reference Output connector RESET Sets the ASX 16C D to the same power on state created by pressing the Front Panel SLAVE RESET RESET button see Section 1 2 2 This feature is only available on Model ASX 16C D Serial Number 14 and later Smodule Turns off all modules except the two specified
33. git number inserting leading zeros if necessary 17 1 13 Frequency Adjustment Procedure Certain equipment is required to perform this adjustment Model ASX 16C D or Model DTS frequency counter with a resolution and stability appropriate for your adjustments host computer with IEEE 488 bus interface and software Consult Section 1 3 for information on using the ASX 16C D remote control commands 1 Resetthe ASX 16C D by using the front panel RESET button Allow the ASX 16C D to warm up for at least thirty minutes 2 Set the ASX 16C D s RF attenuator to 0 dB using the command 0 3 For Model DTS only make sure the frequency synthesizer is off then switch the GF relay to its IN position using the command GFIN Also make sure the Model DTS s relay is in its GB position using the command 4 off the carriers of all modules using the command 5 single module in this example assume module 1 C1 6 Use the frequency counter to read and record the module s frequency F1 If frequency counter is controllable through the IEEE 488 bus this entire procedure can be automated otherwise it will be necessary to have the measured frequency entered through the computer s keyboard 7 Compute the frequency error If the frequency is within acceptable limits move on to the next module starting with step 4 above 8 Read the current frequency adjustment step for this channel using the FR
34. h the IEEE 488 interface bus Both models are available with either narrow band or wide band filters the designation WB in AAFS 12WB indicates the normal wide band feature The wide band filters are capable of passing a much wider bandwidth than the optional narrow band filters and are used in instances where you need to make multiple distortion measurements using the same filter For example you may need to measure CTB Composite Triple Beat CSO Composite Second Order Carrier to noise and X Mod Cross Modulation distortions all on the same filter Except for the filter bandwidths and the hardware which performs the actual filter selection the narrow band and wide band models function identically 2 6 Operation of AFS 12WB Microcontroller Depending on the configuration of your AFS 12WB on power up or reset the Microcontroller either disables all filters or selects the first filter in the filter bank The normal default especially on units with a Channel display is to select the first filter Depending on the actual configuration the Microcontroller Board receives its commands through the keyboard and or through the IEEE488 bus The keyboard permits selection of a filter using a two button sequence or a three button sequence on units with a 3 digit Channel The previous or next filter can be selected by using the keyboard s Scan Down and Scan Up keys respectively 21 SECTION III Repairs to the Eq
35. ing all module level data to be retained This eliminates the need to re level the ASX 16C D carriers each time the unit is reset The Generator Controller receives its commands through the IEEE488 bus If a command is received which requires a response from the ASX 16C D the Generator Controller responds through the IEEE 488 bus Section of this manual covers the IEEE488 operations of the ASX 16C D 2 3 RF Generator Modules Each module can be independently turned on and off modulated or operated in a CW unmodulated mode When a carrier is modulated the modulating signal is provided by the ASX 16C D s Modulation Generator A Mode control line which runs from the Modulation Generator to all the Generator modules in a daisy chain fashion determines how the Modulation Generator s output should be used When the Mode line is at a low logic level the normal 15 75 Kilohertz square wave is output by the Modulation Generator When the Mode line is at a high level the Modulation Generator reproduces a data stream which contains the control information for one or more of the ASX 16C D s Generator modules This data stream has a serial format consisting of bursts of twenty four pulses and is sent at a bit rate of approximately 15750 bits per second No data clock is required by this data because the bits are self clocking with narrow pulses representing a logic 0 and wide pulses representing a logic 1 20 2 4 Modulation Generator The Mod
36. ion mode by mistake simply enter 000 again to exit 1 6 Remote Control of Model AFS 12WB The Model AFS 12WB can be controlled remotely through the IEEE488 bus Most remotely controlled equipment made by Matrix Test Equipment uses two types of IEEE 488 commands SLAVE commands and HANDSHAKE commands SLAVE commands are one way commands which are executed if possible as soon as they are received HANDSHAKE commands utilize two way communications and are more complicated in their operation The Model AFS 12WB uses both kinds of commands Any space characters embedded in commands received through the IEEE488 bus are ignored by the Model AFS 12WB Commands can contain either UPPER CASE or lower case letters Commands sent to the Model AFS 12WB be terminated with either carriagereturn line feed ASCII code 13 followed by ASCII code 10 or with just a line feed character When a filter number is specified in the following chart the filter number should be an integer from 1 to N where N is the highest filter number in your system The Filter Designation Sheet included with your unit indicates the relationship between the filter number and its frequency The following commands are available on the Model AFS 12WB Command literals are indicated in UPPER CASE variables are indicated in lower case 12 1 7 AFS 12WB COMMANDS SIGNAL MEANING TYPE EX Ffilter Causes the specified filter to be selected SLAVE F1 F16 FAmaxpo
37. lowing commands OUTPUT 723 FA8 or OUTPUT 723 1 9 Adjusting the Output Levels of the ASX 16C D The first step in leveling the ASX 16C D s output is to measure the amplitude of a typical carrier usually one near the middle of the ASX 16C D s frequency spectrum The RF attenuators are then adjusted using the ASX 16C D s A or V commands to bring the carrier level of this typical carrier to within one dB of the desired level The final fine tuning of carrier amplitudes is performed using the ASX 16C D s L command This allows the individual modules to be leveled or sloped exactly as required by a particular application 13 To perform the leveling an external power meter or spectrum analyzer or similar device must be used In order to cover all possible power measuring devices a procedure rather than a complete program is provided 1 Set up the ASX 16C D s RF attenuators as described in the first paragraph of Section 2 5 7 2 Turn off all ASX 16C D carriers using the command 400 OUTPUT 724 3 Set the variable M to the module number of the module which is to be turned on then turn on this module using the command 500 OUTPUT 724 C M 4 Measure the output level of the module to see if it is close enough If the Level is acceptable skip to Step 6 If the level is not acceptable generate an error value E by using the following formula E is the error R is the power meter reading D is the desir
38. maintain compatibility with older user written programs Note that the comma must be sent The response from the ASX 16C D is either an N for no go cannot move by that number of steps or a G for go can move by that number of steps When a module s level is changed its carrier is automatically turned on CW When the specified module number is 0 Zero indicating all modules if any module cannot be stepped by the requested amount an N response is generated and no levels are changed NOTE In the low resolution mode each module has a range of approximately 15 dB which is covered by a 150 steps range of adjustment from 0 to 150 In the high resolution mode each module has a range of approximately 15 dB which is covered by a 600 steps range of adjustment from 0 to 600 The change in dB per step has a linearity error of approximately 0 25 dB over each 5 dB portion of the15 dB adjustment range Sets the indicated module s carrier level up unsigned or down minus sign by the requested number of steps in the high resolution mode There are 721 steps from 0 to 720 Each step is approximately 0 025 dB This command has four times the resolution of the older Lmodule steps command which has been retained to maintain compatibility with older user written programs Note that the comma must be sent The response from the ASX 16C D is either N for no go cannot move by that number of steps or a G for go can
39. ng the maximum 25 5 dB range of adjustability for all modules to approximately 15 dB 6dB 9dB This 15 dB range is associated with 600 Step Levels in high resolution instead of the maximum of 1020 The most recent Step Level data for each module is stored in the ASX 16C D s battery backed up RAM retaining the information even when the ASX 16C D is reset or turned off In addition to the Step Level each generator module has its own Base Level stored in the same protected RAM This Base Level establishes the base lowest level of a module s 15 dB range of adjustability This relationship is illustrated in Figure 2 By raising or lowering the Base Level setting a module s maximum output power can be raised or lowered respectively Because the maximum Step Level for a module is 720 maximum Base Level is step 300 Figure 3 illustrates the outputs of three modules before Base Level calibration Even though all modules are set for their default level of Step 480 and are set to their maximum Base Level of 300 their output levels vary over a 4 dB range due to the difference in their output stages and output filters For the sake of this discussion let us assume that the weakest module in the ASX 16C D is the one with an output of 9 dBm the module on the left Figure 4 illustrates the outputs of the same modules after Base Level calibration Note that when properly calibrated all modules produce a flat output level when all are set
40. ock diagram of Figure 1 illustrates the ASX 16C D s major interconnections The Model AFS 12WB contains a bank of remotely selectable RF filters as detailed in Figure 5 and Section 2 5 For the Model DTS information on controlling any additional equipment can be found in the manuals provided by the additional equipment s manufacturers and DTC C ATI 100 Software User Manual 1 2 Features of the ASX 16C D The basic Model ASX 16C D contains a bank of crystal controlled modules which can be individually turned on turned off 100 percent modulated with a 15 75 KHz typical square wave set for CW no modulation and output level adjusted over approximately a 15 dB range This 15 dB range allows the outputs of individual carriers to be individually adjusted tilted to match specific application requirements The linearity of output level adjustment is approximately plus or minus 0 25 dB deviation over each 5 dB of this 15 dB range The output of this module bank is passed through an RF attenuator which can be varied over a typical range of 0 to 81 dB in 1 dB steps An optional 0 5 dB step attenuator is also available In some units the modulation frequency can be changed to 1 KHz thereby allowing special distortion measurements to made with an improved noise floor If your DTS C is equipped with a Frequency Synthesizer special ASX 16C D commands may allow its signals to be used separately or to be combined with the carrier signals from the AS
41. odule s Base Level is set its carrier is automatically turned on CW A module value of 0 zero will cause the command to be carried out on all the modules The Bmodule level command is ignored if the Base Level flag is set Resets of the ASX 16C D will not affect the Base Levels if the BD command has been used to set the Base Level flag Note that the comma must be sent Note Base Level commands are normally for factory use only used when the Base Levels are first set Periodic adjustments to the Base Level are usually not necessary except when the ASX 16C D battery backed up memory has become corrupted or has been replaced Clears the Base Level flag in the ASX 16C D s battery backed up RAM Only when this flag is cleared can the Base Levels be adjusted using the Bmodule level command Do not use this command until you have received proper training from Matrix Test Equipment If this flag is not set before the unit is reset or the power is turned off the Base Levels of all channels will be automatically set to 75 on the next reset or power up Sets the Base Level flag in the ASX 16C D s battery backed up RAM When this flag is set commands to adjust the Base Levels Bmodule level are ignored When this flag is set the Base Levels are unaffected by resets and power up Requests the status of the Base Level Done flag If the flag has been set using the BD command the response from the ASX 16C D is S If the flag is not cleared
42. ource into and out of the RF circuit In a Model DTS removes power from the Noise Source Removes the RF bypass which is caused by the BYPASS command Changes the output termination characters for data transmitted from the ASX 16C D to be carriage return line feed NOTE The OUT commands do not affect the requirements for data to the ASX 16C D Commands to ASX 16C D can be terminated with either carriage return followed by a line feed or with just a line feed Changes the output termination character for data transmitted from the ASX 16C D to carriage return only See the NOTE above This 15 the reset power up default mode Shuts off the carrier of the specified module in accordance with the mode set by the Q command see below If the module number is 0 zero the carriers of all modules are shut off Sets the Quality factor of the off discussed in the P S commands the QLOW mode all off carriers are unmodulated with their amplitudes at least 35 dB lower than normal Activating the QLOW mode does not affect the pre existing conditions of the modules The QLOW command affects only those modules which are subsequently turned off using the P S or T command The ASX 16C D powers up in the QLOW mode Sets the Quality factor of the off discussed in the P S T commands the QOFF mode all off modules have their power removed In this mode the oscillators will cool off
43. r s access address If the problem stays with the access address the problem is in the filter selection circuitry If the problem stays with the filter the filter has failed or has become mis tuned 22 On the wide band AFS 12WB units an array of light emitting diodes LEDs on the boards indicate which relays have been selected This may aid you in hunting down a bad coaxial connection or a bad relay 3 4 Miscellaneous Repairs The only ICs which cannot be substituted for using commercially available components are the PROMs on the ASX 16C D and AFS 12WB Controller boards Replacement PROMs for your equipment are available from Matrix Test Equipment 23 SECTION IV SPECIAL DTS DISTORTION MEASUREMENTS 4 1 Introduction The Model DTS can be outfitted with equipment which allows distortion measurements to be made with a much better noise floor than a conventional spectrum analyzer a Model AR 12 a Model R 12 a Model R 75 or a Model R 76 Typical equipment needed to use these special measurement techniques are one from each category is required Matrix Test Equipment ASX 16C D or DTSB Signal Generator Matrix Test Equipment AFS 12WB or DTS Filter Bank Agilent HP 8591E RF Spectrum Analyzer Agilent HP 8657A Frequency Synthesizer Standard Research Systems Audio Spectrum Analyzer The examples given in Section 4 2 are based on this list of equipment The Generator ASX 16C D and Filter Bank AFS 12WB are assumed
44. s Causes the Model AFS 12WB to begin an automatic scanning of its filters from the SLAVE FA7 first position to the maximum position number which was specified by the data FA12 maxpos Note that this is the position number and not the usual filter designation Example Assume your Model AFS 12WB has twelve 12 filters with designations 2 4 5 6 8 9 10 12 14 15 17 and 20 If you want a rapid scan of filter 2 in the first position through filter 20 in the twelfth position use the command FA12 Scanning will continue endlessly until either the AFS 12WB is turned off or until the AFS 12WB is reset by simultaneously pressing the and keys This command is primarily intended for factory testing purposes FV Requests the current filter number Response from the AFSW is a three digit number HANDSHAKE FV with leading zeros as necessary indicating the 3 digit identification of theFilter currently selected 1 8 Typical Software for the Model AFS 12WB The examples in this section are written in Hewlett Packard Basic compatible with many HP computers Some modifications may be necessary to adapt these examples for use with other computers As shipped from the factory the Model AFS 12WB is set for IEEE 488 bus address 23 To select filter number 5 use either of the following commands OUTPUT 723 F5 OUTPUT 723 5 To enable automatic filter scanning from filter position 1 through filter position 8 use either of the fol
45. t fifteen minutes Set the ASX 16C D s RF attenuator to 10 dB using the command A10 Put all modules on level step 480 using the command 0 480 Set the Base Level of all modules to step 300 using 0 300 Turn off the carriers of all modules using the command PO Turn on a single module in this example assume module 1 C1 Use the power meter to read and record the module s output power Repeat Steps 5 through 7 recording each module s output power level Using the output power data locate the module whose output was lowest weakest The power output of the weakest module is called the Reference Level 10 Turn off the carriers of all modules using the command Turn on a single module in this example assume module 1 C1 Use the power meter to read the module s output power If the power level is within 0 25 dB of the Reference Level skip to Step 17 If the power level is more than 0 25 dB higher than the Reference Level the module s Base Level is set too high Read the module s Base Level setting using the following HANDSHAKE command again we will assume module 1 BVH1 Don t forget to complete the HANDSHAKE Each high resolution Base Level step changes the output power by approximately 0 025 dB Increase or decrease the Base Level value as appropriate then send the new calculated Base Level to the ASX 16C D using the following command assume the new Base Level should be 264 and assume we are s
46. that is if a module is left off while the QOFF mode is active It will not be at its warmed up frequency when power is reapplied Activating the QOFF mode does not affect the pre existing condition of the modules The QOFF command affects only those modules which are subsequently turned off using the P S or T command TYPE SLAVE SLAVE SLAVE SLAVE SLAVE SLAVE SLAVE SLAVE SLAVE NON NOFF NORMAL OUTCRL F OUTCR 1 121 P0 QLOW QOFF SIGNAL MEANING TYPE EX Rdata In a Model DTS configures the R internal relays and or optional the relays located SLAVE see below in the white box the test switch fixture The data portion of the command specifies the new positions for all these In the standard Model DTS There are eight 8 R relays or sets of relays Additional relays can be added In the data portion of the command positions are specified in order relay 1 first relay 8 last All eight of the relays must be specified even if their switching positions do not matter in that particular test configuration and even if your configuration does not contain the full set of eight relays U puts a relay in its Up position D puts a relay in its Down position X indicates that the relay s position is unimportant WARNING the X does not mean that the former relay position will be retained You should only use X if you really don t care which position that relay is in I
47. till using module 1 B1 264 Go back to Step 14 If the reading is still not correct continue to adjust the Base Level If the Base Level value goes below 0 or above 300 something is wrong with either the module power meter or with the RF connections When the module s power output is correct repeat Steps 10 through 16 for the next module When all modules have been completed use the BD command to set the Base Level Done flag in the ASX 16C D by sending to the ASX 16C D the command BD 16 1 12 Adjusting ASX 16C D Oscillator Frequencies The operating frequency of each ASX 16C D generator module can be adjusted over a 4096 step range to compensate for age related frequency drift in the oscillator crystals The FR and FRVA commands are used to make the adjustments The FR command is used to adjust the frequency of each module The general form of this command is FRmodule change where module specifies the module whose level is to be adjusted and change specifies the amount of adjustment to be made Examples FR2 250 FR4 12 FR45 0 The command is slave command error checking is performed therefore it is important that you read this section completely before attempting any frequency adjustments The change vaue is limited to a range of or 255 steps however the FR command can be sent several times to the ASX 16C D if you need to move the adjustment by more than 255 steps If the
48. to be part of a Model DTS 4 2 Flow Charts The following flow charts provided are based on the configuration outlined in Section 3 1 The same processes can be used with other equipment providing they perform the same function The flow charts show how to perform Composite Triple Beat CTB Composite Second Order Beat CSB and Cross modulation X mod measurements Certain conventions are used in the flow charts A plain language description is listed first This may be followed by a comment enclosed in square brackets Brackets will contain subsidiary information and assumptions used in example instructions Below these lines is a line enclosed in parentheses The parentheses provide a sample instruction line for the specified device This is supplied as a guide for anyone writing a program to control all the equipment These commands are provided only as a guide Additional commands may be required If the phrase USE A SUBROUTINE appears a step it indicates that a multi line subroutine will be required to perform the step Some steps may be common to the three types of distortion measurements DUT is the abbreviation for Device Under Test S A is the abbreviation for Spectrum Analyzer When making measurement on HP S A allow at least one half second for settling When making measurements 5 5 S A allow at least one second for settling 24 CTB CSB SETUP SET ASX 16C D TO OBTAIN THE DESIRED OUTP
49. uipment 3 1 Introduction Repairs to the Model ASX 16C D and AFS 12WB are discussed in the next two sections Because the Model DTS typically contains both an ASX 16C D and an AFS 12WB these sections also apply to the DTS Repairs to a DTS system fall into five general categories 1 Generator Modules 2 AFS 12WB filter selection 3 Main Frame Harnessing 4 Support Equipment Controllers driver boards et cetera 5 Equipment Not Manufactured By Matrix Test Equipment The first four groups are covered in the chapters below For repairs to equipment not manufactured by Matrix consult the manuals supplied by the equipment s manufacturer 3 2 Repairs to the Generator Modules There are four ways in which a Generator module can fail 1 Unstable Intermittent Operation or No Output Power 2 Always CW no modulation 3 Always Modulated 4 Response to L Leveling commands Any of these problems can be caused by bad continuity between the module and the control wiring power wiring or coaxial cables First check all coaxial connectors and wiring connections All modules receive their control signals from the Modulation Generator If only one module is malfunctioning the problem is in that module If the problem affects an entire section of modules the problem is most likely in the cabling If all modules are affected the problem may be in the modulation generator or in the cables leading to or from the Modulation Generator
50. ulation Generator s circuit is a crystal oscillator followed by a frequency divider In most units the oscillator operates at 15 75 Megahertz its output frequency is divided by one thousand to 15 75 Kilohertz KHz In some units an alternate modulation frequency of 1 KHz is also included This optional feature can be used to improve the noise floor for some distortion tests The modulations generator s signal is passed through a series of gates selectors which allow the Modulation Generator s output to be set to any one the following four conditions 1 Normal Modulation continuous square wave 2 High Level DC modulation disabled high 3 Low Level DC modulation disabled low 4 Data From Generator Controller serial data for modules The selected output signal one of the above four is passed to a buffer circuit whose output is capable of driving the inputs of all the ASX 16C D modules On units equipped with the 1 KHz option one of the disabled states is replaced by the 1 KHz output state The Modulation Generator also produces a buffered copy of the Generator Controller s Modulation Data Mode signal This Mode signal is passed to all the ASX 16C D modules 2 5 AFS 12WB Filter Selectors The Model AFS 12WB is a remotely controllable unit which is also available with optional manual controls Both units contain a bank of filters which can typically be selected one at a time Remote control operations are performed throug
51. uses all modules which are set for 100 modulation to operate as if they were set for CW operation All modules which are set for CW operation will function normally Under certain circumstances this feature can save programming steps or time such as when switching from an X mod test to a CTB test PE HANDSHAKE HANDSHAKE SLAVE SLAVE SLAVE SLAVE SLAVE SLAVE EX FRVA1 FRVA122 FRV1 FRV122 FS GEN GFIN GFOUT HH HL SIGNAL HU K optional Lmodule steps LHmodule steps LMmodule LMHmodule MEANING Restores the Modulation Generator s normal operation Requests the ASX 16C D s customer programmed identification number This ID number is programmed by setting the CUSTOMER DEVICE IDENTIFIER switches on the ASX 16C D s Microcontroller board The response from the ASX 16C D is a three digit number from 000 to 099 Requests the status of the test module switch located on the test switch fixture Response from the ASX 16C D is either N switch is open or G switch is closed Sets the indicated module s carrier Level up unsigned bor down minus sign by the requested number of steps in the low resolution mode There are 181 steps from 0 to 180 Each step is approximately 0 1 dB This command has been replaced by the LHmodule steps command which has four times the resolution approximately 0 025 dB per step The Lmodule steps command has been retained to
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