Programming a Downlink Multi-Tone Audio Measurement

Last updated: December 3, 2008

This measurement is not applicable to GPRS or EGPRS.

This section provides an example of how to use the Multi-tone Audio instrument via the GPIB for performing measurements on a mobile station's speaker.

The following procedure assumes that a mobile station is connected to the test set's RF IN/OUT and that the mobile station's speaker is connected to the AUDIO IN BNC connectors. See Multi-tone Audio Measurement Description .

Set the traffic channel speech type to Multi-tone.
Configure the multi-tone audio measurement for measuring the frequency response and absolute audio level of the mobile station's speaker. The SETup subsystemes used for configuring parameters. Parameters that must be configured include:
- Measurement Mode - must be set to Downlink
- SINAD/Distortion State - must be turned off to capture frequency response results.
- Expected Audio In Peak Voltage - must be set to avoid over or under range errors.
- Generator's Total Audio Level - should be set as high as possible. This setting is dynamic and varies depending on the generator frequencies selected.
Other parameters can also be configured as illustrated in the following programming example. See Measurement Parameters for more information.
Start the multi-tone measurement using the INITiate subsystem.
Use the FETCh? subsystem to obtain multi-tone audio measurement results.
Reconfigure the multi-tone audio measurement for performing a SINAD/Distortion measurement.
- SINAD/Distortion State - turn the state on so SINAD and Distortion measurement results will be available.
- Generator Preset Frequencies - a preset with audio tone one turned on and all other tones turned off must be used for SINAD/Distortion measurements.
Start the multi-tone measurement again using the INITiate subsystem.
Use the FETCh? subsystem to obtain multi-tone audio SINAD/Distortion measurement results.

Programming Example

 
1 DIM UL$[100]   ! String to hold data for MTA downlink upper Limits
2 DIM LL$[100]   ! String to hold data for MTA downlink lower Limits
3 !
4 DIM Mta_levels(20)   ! Arry to hold MTA measurement results
5 ! including integrity indicator
6 !
7 !*** Define Pass Fail Limits for all 20 tones ***
8 !
9 UL$ = "-11,-12,-12,-12,-12,-8,-10,-12,-12,-10,-13,-11,-14,-13,-12,-8,-5,-2,0,-1"
10 LL$ = "-15,-16,-16,-16,-16,-12,-14,-16,-16,-14,-17,-15,-18,-17,-16,-12,-9,-6,-4,-5"
11 !
12 OUTPUT Testset;"SETUP:MTA:LEVEL:ALL:LIMIT:UPPER "&Mta_dnlink_ul$
13 OUTPUT Testset;"SETUP:MTA:LEVEL:ALL:LIMIT:LOWER "&Mta_dnlink_ll$
14 !
15 !*** multi-tone audio measurement setup ***
16 !
17 !  Turn Off Uplink Generator
18 OUTPUT Testset;"SETUP:MTAUDIO:GEN:LEVEL:UPLINK:ALL:TOTAL 0"
19 OUTPUT Testset;"CALL:TCH:DOWNLINK:SPEECH MTA"
20 ! DOWNLINK MEASUREMENT MODE
21 OUTPUT Testset;"SETUP:MTAUDIO:MEAS:MODE DOWNLINK"
22 !  SET SINAD DISTORTION STATE TO OFF 
23 OUTPUT Testset;"SETUP:MTAUDIO:SDIS:STATE 0"   
24 !  PRESET 100 HZ SPACING
25 OUTPUT Testset;"SETUP:MTAUDIO:GEN:FREQ:PRESET MTA100"   
26 OUTPUT Testset;"SETUP:MTAUDIO:COUNT 5"   !averaging of 5
27 !  Set absolute reference level
28 OUTPUT Testset;"SETUP:MTAUDIO:REF:ABS:LEVEL:DOWNLINK .3"  
29 !  EXPECTED VOLTAGE OF 1 VOLT
30 OUTPUT Testset;"SETUP:MTAUDIO:PEAK:VOLT 1"   
31 OUTPUT Testset;"SETUP:MTAUDIO:SETT .1"   !  SETTLING TIME OF .1 SECONDS
32 !  TOTAL GENERATOR LEVEL
33 OUTPUT Testset;"SETUP:MTAUDIO:GEN:LEVEL:DOWNLINK:ALL:TOTAL 25"
34 !
35 !*** Multi-tone audio individual 20 tone level measurements
36 !
37 OUTPUT Testset;"INIT:MTA"
38 !
39 OUTPUT Testset;"FETCH:MTA:LEVEL?"
40 ENTER Testset;Mta_levels(*)
41 !
42 OUTPUT Testset;"FETCH:MTA:INTEGRITY?"
43 ENTER Testset;Integrity
44 !
45 OUTPUT Testset;"FETCH:MTA:VOLTAGE?"
46 ENTER Testset;Dnlink_volts
47 !
48 !
49 OUTPUT Testset;"FETCH:MTA:LEVEL:LIMIT:FAIL?"
50 ENTER Testset;Pass_fail
51 !
52 SELECT Pass_fail
53 !
54   Case 0
55     Pass_fail$ = "Passed"
56   Case 1
57     Pass_fail$ = "Failed"
58   Case Else
59     Pass_fail$ = "Unknown"
60   End Select
61 !
62 !*** DownLink Distortion Test
63 !
64 OUTPUT Testset;"SETUP:MTAUDIO:COUNT 3"   !averaging of 3
65 !  SET SINAD DISTORTION STATE TO ON
66 OUTPUT Testset;"SETUP:MTAUDIO:SDIS:STATE 1"   
67 !  PRESET SINE 1000 HZ SINGLE TONE
68 OUTPUT Testset;"SETUP:MTAUDIO:GEN:FREQ:PRESET SIN1000"   
69 OUTPUT Testset;"SETUP:MTAUDIO:REF:ABS:LEVEL:DOWNLINK .5"
70 !
71 OUTPUT Testset;"INIT:MTA"
72 !
73 OUTPUT Testset;"FETCH:MTA:DISTORTION?;SINAD?;VOLTAGE?"
74 ENTER Testset;Dnlink_dist,Dnlink_sinad,Dist_volts
75 !
76 !*** Print Results ***
77 !
78 Print
79 Print_title ("MultiTone Audio Downlink Test")
80 Print_results("Channel= ",Current_chan,"")
81 Print
82 !
83 Print_results("Integrity indicator = ",Integrity,"")
84 Print
85 Print_results("Downlink Audio Level =",Dnlink_volts," V")
86 Print
87 !
88 For I = 1 To 20
89   Print_results("Tone "&VAL$(I),Mta_levels(I)," dB")
90 Next I
91 !
92 Print_res_str("Test Result: ",Pass_fail$)
93 Print
94 !
95 Print_results("Downlink Distortion 1000 Hz =",Dnlink_dist," %")
96 Print_results("Downlink SINAD 1000 Hz =",Dnlink_sinad," dB")
97 Print_results("Downlink Level 1000 Hz =",Dist_volts," V")

Programming a Downlink Multi-Tone Audio Measurement

Programming Example

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