Sailor RE2100, Техническое руководство

Страница: 42 / 186

3 SERVICE RE2100
5.
6. Measurement of the signal to noise SND/N.
With the specified test signal applied to the receiver, the measurement of SND/N is performed as
described below.
SSB MODE
a.
Turn the RF-GAIN control fully clockwise and make sure that the AGC is operative.
b. Notice the output LF level by means of a voltmeter.
c. Turn the AGC OFF and adjust the RF-GAIN control to achieve the output level found in point
6.b.
d. Change the signal generator frequency f
G
to f
RX
+ 30 kHz and notice the reduction of the
LF output level, which expresses the signal to noise ratio.
AM MODE
e.
Turn the RF-GAIN fully clockwise and make sure that the AGC is operative.
f. Notice the output level by means of a voltmeter.
g. Remove modulation from the generator signal and notice the reduction of the output, which
expresses the signal to noise ratio.
3.5.2.2 PERFORMANCE CHECK OF RECEIVER DISTORTION
To carry out the check as described below, it is necessary to have a distortion meter at your disposal. If
this is not possible, the check can be done by an oscilloscope, but please note that it should not be possible
to see a distortion of 10% or less on the oscillocope.
1. Connect a distortion meter to the 0 dBm output on the testbox.
2. Connect a signal generator to the aerial socket through a 50 ohm dummy load.
3. Choose receiver frequency f
RX
generator frequency f
G
and generator output level V
G
according to
point 5.
PAGE 3-12