3. Assume that the unloaded Q of the power amplifier (V9) tank circuit is 180,
and the loaded Q is 9.
The transfer efficiency of the tank circuit is
approximately
a. 75 percent.
c.
95 percent.
b. 85 percent.
d.
100 percent.
4. After changing V5 to a quadrupler to eliminate the first doubler, it is found
that parasitic oscillations occur. These parasitics can be suppressed by inserting
a
a. parallel-tuned trap in the screen grid lead.
b. series-tuned circuit in the control grid lead.
c. small high-frequency capacitor between pins 3 and 5 of V5.
d. small resistor in the lead between pin 5 of V5 and pin 1 of transformer
T1.
5. Analysis of the transmitter circuit shows that the coupling circuit between
a. inductive with link coupling.
b. capacitive with a split-stator tuned circuit.
c. capacitive with the control grid at RF ground.
d. inductive with tuned primary and untuned secondary.
6. Assume that a given portable, direct FM transmitter contains a 20.850-MHz
oscillator, a frequency doubler, and a power amplifier.
If the frequency of the
oscillator swings between the limits of 20.848 MHz and 20.852 MHz while being
modulated, the frequency deviation of the transmitter is
a. 2 kHz.
c.
8 kHz.
b. 4 kHz.
d.
10 kHz.
7. Analysis of the ib - ec curve for a given electron tube shows that the grid
cutoff voltage --8 volts, grid voltage at plate saturation = +2 volts.
If this
tube is to be used as a doubler in an FM transmitter, its operating bias must be
adjusted to approximately
a. -20 volts.
c.
-4 volts.
b. -8 volts.
d.
+2 volts.
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