TB 9-4931-488-35
Table 20. AM Accuracy
Measuring receiver
Test
Indications
Instrument
(% AM)
Meter
Min
Max
Indications
90
83.6
96.5
70
64.7
75.4
50
45.8
54.3
30
26.9
33.2
20
17.4
22.6
10
7.95
12.1
(10) Press LEVEL VOLTS pushbutton and adjust OUTPUT LEVEL vernier
control(s) for a +3 dB indication on TI meter.
(11) Adjust AM control for a 50% AM indication on measuring receiver. The
distortion, as indicated on the audio analyzer will be within limits listed in table 21.
(12) Repeat technique of (10) and (11) above for TI meter dB indications and
measuring receiver % AM indications listed in table 21. The audio analyzer distortion
indications will be as specified.
Table 21. AM Distortion
Test instrument
Measuring receiver
Audio
meter indications
indications
analyzer
(dB)
(% AM)
indications
(<%)
+3
50
1
+3
90
3
-7
90
3
-7
50
1
-71
30
10
-71
90
20
1
Perform for option 002 only. Set RANGE MHz switch to 1024-512 and adjust FREQUENCY TUNE control for a
FREQUENCY MHz display indication of 1024 MHz.
b. Adjustments
(1) Position controls as listed in (a) through (f) below.
(a)
AM switch to AC.
(b)
AM control fully cw.
(c)
OUTPUT LEVEL vernier control(s) fully cw.
(d)
RANGE MHz switch to 64-32.
(e)
50 MHz.
(f) RF OFF/ON switch to ON.
(2) Set Audio analyzer for a 1 kHz .7072 V 600 Ω output signal.
30
