Sailor RE2100, Technical Manual

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3 SERVICE RE2100
3.6.1.7 CHECK OF AF FILTERS
The audio frequency selectivity is controlled by measuring the overall selectivity of the receiver.
If the measured data cannot fulfil the specified requirements, it is necessary to control the 2nd IF
selectivity before any conclusion can be made.
SSB MODE
1. Connect the generator to the aerial socket at the front end unit (module 2).
2. Connect the voltmeter and the counter to testpoint TP2-1 (earpiece output).
3. Turn the RE2100 on and turn the RF gain control fully clockwise.
4. Choose generator frequency f
G
, generator output level V
G
, and receiver frequency f
RX
according to
point 11.
5. Make sure that J3E mode (SSB) is selected, that AGC in on, and that the AF signal frequency is
approx. 1 kHz.
6. Finetune the receiver frequency by means of the arrow keys until maximum meter deflection when
measuring at testpoint TP2-1.
7. Notice the AC voltage at testpoint TP2-1.
8. Turn the AGC off and adjust the RF gain control to achieve the output level found in point 7.
9. To check the 6 dB bandwidth, choose the generator frequencies 1990.35 kHz and 1992,70 kHz and
control in each case the AC voltage at testpoint TP2-1 not to decrease more than 6 dB relative to
the value measured in point 7.
10. To check the stopband attenuation, choose the generator frequency 1993,1 kHz and control the AC
voltage at testpoint TP2-1 to decrease more than 20 dB relative to the value measured in point 7.
11.
AM MODE
12. Repeat point 1-4.
13. Make sure that H3E mode (AM) is selected, that AGC is on, and that the AF signal frequency is
approx. 1 kHz.
14. Finetune the receiver frequency by means of the arrow keys until maximum meter deflection at
testpoint TP2-1.
15. Notice the AC voltage at testpoint TP2-1.
16. To check the 6 dB bandwidth, change the modulation frequency of the generator to 100 Hz and
3000 Hz, and control in each case the AC voltage at testpoint TP2-1 not to decrease more than
6 dB relative to the value measured in point 15.
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