a. linear detector.
c. square-law detector.
b. full-wave detector.
d. weak-signal detector.
2. The infinite-impedance detector and the plate detector are used in circuits
where strong signals are to be expected.
Compared with the plate detector,
however, the infinite-impedance detector has the advantage of
a. providing an AVC voltage.
b. providing high selectivity.
c. high signal sensitivity.
d. linear operation with both very weak and very strong input signals.
3. A bandwidth of 10 kHz is considered sufficient for IF bandpass requirements
in typical AM receivers, but much narrower bandwidths are permissible in some
receivers.
The purpose of using bandwidths that are narrower than 10 kHz in
military communications is to
a. prevent distortion.
b. furnish optimum gain.
c. provide faithful reproduction of speech and music.
d. provide a compromise between intelligibility and interference rejection.
4. A typical IF amplifier circuit is shown in figure 187 of TM 11-665.
The
purpose of R3 and C6 is to
a. isolate the amplifier from the power supply.
b. provide feedback to sustain oscillations.
c. filter RF frequencies from the carrier.
d. flatten IF response.
5. When three IF amplifier stages are used together in a superheterodyne
receiver, stray coupling tends to cause the amplifiers to oscillate.
Instability
due to such oscillations can be reduced by
a. using bypass capacitors, shielding the circuits, or designing the circuits
carefully.
b. shielding the circuits, designing the circuits carefully, or using remote
cutoff tubes.
c. designing the circuit carefully.
using remote cutoff tubes, or using
bypass capacitors.
d. using remote cutoff tubes, using bypass capacitors, or shielding the
circuits.
322 L3
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