13.
The noise generator method of obtaining the noise figure has the advantage over other methods because
a.
the ac input reading of the generator can be converted to give the true noise figure.
b.
it is not necessary to know the gain or response characteristics of the receiver.
c.
noise generators are usually available when other generators are not.
d.
no equipment is necessary with this method.
14.
Each microwave terminal contains an assembly that compresses the dynamic range of the voice-
frequency signals to be transmitted and expands the received voice-frequency signals to their original
condition. This assembly is known as a
a.
compandor assembly.
c.
compressor assembly.
b.
deemphasis assembly.
d.
mode selector assembly.
15.
The performance computation that provides an indication of a receiver's relative noisiness on a day-to-day
basis is called the
a.
Y factor.
c.
improvement factor.
b.
noise power.
d.
threshold temperature.
16.
Which receiver parameter has the greatest effect on the output S/N?
a.
Gain
c.
b.
d.
Frequency
17.
To what receiver function is the improvement factor Fm related?
a.
AGC
c.
Selectivity
b.
Gain
d.
Demodulation
18.
The maximum improvement factor obtainable from an AM receiver that is using automatic gain control is
a.
0.5.
c.
6.0.
b.
1.0.
d.
150.
19.
If a frequency-modulated signal has a modulation index of 4, the value of the improvement factor Fm is
approximately
a.
8 db.
c.
22 db.
b.
13 db.
d.
150 db.
344 L4
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