d. changes its power relationships with time.
6. How is a continuous-wave radiotelegraph signal made audible in a radio receiver?
a. The RF amplifier converts the received signal to AF energy.
b. The AF amplifier feeds back parts of its output energy to the RF amplifier.
c. The signal from a beat-frequency oscillator beats with the incoming RF signal to produce an AF
7. The primary reason that CW signals can be heard over greater distances than signals produced by other
radio communication systems is that CW transmission uses
a. low-speed keying.
b. the international Morse code.
d. more power in its signal peaks than any other radio transmission system.
8. Assume that a radio receiver is tuned to receive a tone-modulated signal. One stage in the communication
receiver that is NOT used is the
c. radio-frequency amplifier.
d. audio-frequency amplifier.
9. The function of a modulator in an AM radio transmitter is to
a. heterodyne the AF signal with the RP carrier.
b. rectify the combined AF and RF signals.
c. amplify the AF microphone signals.
d. generate the RF carrier frequency.
10. Assume that a radio transmitter is sending out a mark signal on 1,725.425 kHz and the space signal will
be lower in frequency. The space signal will go out at a frequency of