TB 9-4931-488-24
16. AM Sensitivity, Accuracy, Distortion, and Demodulated Output (Models
Containing Option 004)
a. Performance Check
(1) Connect equipment as shown in figure 5.
(2) Position controls as listed in (a) through (m) below.
(a) COUNTER MODE INT EXT pushbutton pressed.
(b) COUNTER MODE EXPAND X10 and X100 pushbuttons released.
(c) COUNTER MODE LOCK ON pushbutton released.
(d) AM X10% pushbutton pressed.
(e) AM switch to DC.
(f) AM control fully cw.
(g) FM switch to OFF.
(h) RANGE MHz switch to 512 - 256.
(i) FREQUENCY TUNE control for FREQUENCY MHz display indication of 500 MHz.
(j) OUTPUT LEVEL 10 dB switch to +10 dBm.
(k) OUTPUT LEVEL 1 dB switch to 0 dBm.
(l) OUTPUT LEVEL vernier control fully cw.
(m) RF OFF/ON switch to ON.
(3) Set measuring receiver to acquire the frequency then measure AM depth with
peak + detector. Set high-pass filter to 50 Hz and low-pass filter to 15 kHz.
NOTE
In techniques (5) and (8) below, record measuring receiver %
AM display indication using peak + -/2 detector. Average the
indications and use the average for determining the results.
(5) Adjust pulse generator output controls for the first entry under `Pulse generator
output level' in table 22. If the measuring receiver does not indicate between min and max
limits listed in table 22, perform b below.
(6) Repeat technique of (5) above for remaining pulse generator output levels listed
in table 22.
Table 22. OPT 004 AM Sensitivity.
Measuring receiver % AM indications (%)
Pulse generator
output level (V rms)
Min
Max
0.636
85.5
94.5
0.495
66.5
73.5
0.354
47.5
52.5
0.212
28.5
31.5
0.141
19.0
21.0
0.071
9.5
10.5