9960 FM DEVIATION PERFORMANCE TEST.

TM 11-6625-2975-40

2=8. MODULATION TONE DISTORTION PERFORMANCE TEST. (CONT)

PROCEDURE

1. Enter frequency 108.00 MHz into test set.

2. 30 Hz VAR TONE SELECT key is lit. Extinguish all other TONE SELECT keys.

3. Distortion analyzer should indicate 0.25 percent or less distortion. If not, go to

troubleshooting chart 2-1, sh 7.

4. Enter carrier frequencies and set accompanying modulating (TONE SELECT) frequencies

as listed in the following table. At each setting, check distortion analyzer indication against

distortion limits listed in table next to appropriate frequencies. if distortion analyzer indication is

above limit at any setting, go to troubleshooting chart 2-1, sh 7.

CARRIER

TONE SELECT

MAXIMUM

FREQUENCY (Hz)

Distortion (%)

108.00

1020

0.5

9960

108.00

0.5

108.10

0.25

150

108.10

0.25

75.00

1.0

400

75.00

1300

1.0

3000

75.00

1.0

2-9. 9960 FM DEVIATION PERFORMANCE TEST.

TEST EQUIPMENT REQUIRED: Oscilloscope TEK R5440 with plug-ins 5A48 and 5642

RF Cable RG-58/U

EQUIPMENT SETUP: Connect test set to 115 vac power source.

Connect oscilloscope to test set as indicated in the following diagram.

EL9LY015

Turn on test equipment. Allow at least 30 minutes for warmup.