a. 64 watts.
c. 128 watts.
b. 122 watts.
d. 186 watts.
2. The modulator stage of a transmitter is usually operated as
a. an RF power amplifier.
b. an AF power amplifier.
c. an RF voltage amplifier.
d. an AF voltage amplifier.
3. The method of modulation in which the output varies with the input power
while the efficiency of the modulated stage remains constant is called
a. plate modulation.
b. cathode modulation.
c. grid bias modulation.
d. screen grid modulation.
4. Modulation is produced by changing either the dc input or the stage
efficiency.
The four methods that operate with the changing efficiency are
identified as
a. grid bias, screen grid, cathode, and suppressor grid modulation.
b. suppressor grid, plate, grid bias, and screen grid modulation.
c. cathode, screen grid, plate, and suppressor grid modulation.
d. grid bias, cathode, suppressor grid, and plate modulation.
5. Assume that the modulator stage in a transmitter uses constant efficiency
plate modulation.
100-percent modulation is achieved when the instantaneous
a. zero and three times the dc operating plate voltage.
b. zero and one-half the dc operating plate voltage.
c. zero and twice the dc operating plate voltage.
d. zero and the dc operating plate voltage.
6. When grid bias modulation is used in a transmitter, the excitation voltage is
kept at a low level to
a. provide constant efficiency and output.
b. prevent the tube from being driven to cutoff.
321 L2
8
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