TB 9-6625-2296-24
NOTE
Pressing More (F6) will scroll various options on the bottom of
the display. The options will change the functions assigned to
the F1 through F6 function keys. This may be necessary to
obtain the Freq (F2), Mod (F5), and A Freq (F1) options
required in the following tests.
(14) Set measuring receiver to measure AM depth, with low pass filter of 15 kHz,
high pass filter of 50 Hz, and PEAK/2 detector selected.
Table 16. Amplitude Modulation Distortion.
Test instrument
Measuring receiver
RF
Modulation
Low
High
Distortion
frequency
rate
pass
pass
(%)
121.1 MHz
100 Hz
3 kHz
50 Hz
<1.5
121.1 MHz
1 kHz
3 kHz
300 Hz
<0.7
121.1 MHz
6 kHz
15 kHz
300 Hz
<1.5
121.1 MHz
7 kHz
15 kHz
300 Hz
<2.5
121.1 MHz
10 kHz
15 kHz
300 Hz
<2.5
900
kHz
1 kHz
3 kHz
300 Hz
<5.0
900
kHz
100 Hz
3 kHz
50 Hz
<5.0
900
kHz
10 kHz
15 kHz
300 Hz
<5.0
(15) Press Freq (F2) (Frequency Display Mode) and press DATA ENTRY keys to set
frequency to 750 kHz.
(16) Press A Freq (F1) (AF Frequency Mode) and press DATA ENTRY keys to set
AF FREQ to 100 Hz. Press DATA ENTRY ENTER keys.
(17) Press Mod (F5) (% Modulation Mode) and press DATA ENTRY keys to set
MODULATION to 30%. Press DATA ENTRY ENTER keys.
(18) If measurement receiver indication minus residual AM recorded in (5) above is
not within limits specified in table 17 for appropriate TI setting, perform b below.
(19) Repeat steps (15) through (18) for remaining settings listed in table 17.
Table 17. Amplitude Modulation Accuracy.
Measuring receiver1
Test instrument
indications
Modulation
Percent
RF frequency
rate
modulation
Min
Max
750 kHz
100 Hz
30%
27.00
33.00
750 kHz
100 Hz
60%
54.0
66.0
750 kHz
100 Hz
90%
81.0
99.0
750 kHz
1 kHz
90%
81.0
99.0
750 kHz
1 kHz
60%
54.0
66.0
750 kHz
1 kHz
30%
27.00
33.00
750 kHz
10 kHz
30%
27.00
33.00
750 kHz
10 kHz
60%
54.0
66.0
750 kHz
10 kHz
90%
81.0
99.0
54
