c. the frequency range of one coil and tuning capacitor is limited.
d. interference caused by crowding too many stations on a small portion of
the dial is reduced.
3. One result of adding the screen and suppressor grids to the electron tube has
been to
a. eliminate the necessity for an AVC circuit.
b. increase the ability of a tube to self-oscillate.
c. make it possible to inject two signals into the same tube.
d. reduce the interelectrode capacitance and increase the gain.
4. What is the one characteristic that is common to all frequency converters?
a. All frequency converter circuits require the use of two tubes.
b. The oscillator voltage and the RF signal must be injected at different
electrodes.
c. All frequency converters
use
the
nonlinear
portion
of
the
tube
characteristic for mixing.
d. Since the gain of a frequency converter is slight, signal-to-noise ratio
is not an important consideration.
5. High conversion gain is desirable in a converter stage because the signal
voltage applied to this stage is normally low.
A high conversion gain can be
obtained in the converter stage by
a. maintaining a low value of load impedance.
b. maintaining a high value of conversion transconductance (Gc).
c. isolating the local oscillator from the RF signal circuits.
d. using a converter tube with remote cutoff characteristics.
6. In the frequency conversion circuit shown in figure 174 of TM 11-665, the
oscillator signal is coupled to the mixer stage by the grid injection method. When
this method of coupling is used, maximum conversion gain is obtained by
a. keeping the oscillator voltage to a value less than the signal voltage.
b. adjusting the bias to a value approximately equal to the signal voltage.
322 L2
12
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