B-003-13: Frequency and phase modulation fundamentals
B-003-13-01:
What may happen if an FM transmitter is operated with the microphone gain or deviation control set too high?
It may cause interference to other stations operating near its frequency
It may cause digital interference to computer equipment
It may cause atmospheric interference in the air around the antenna
It may cause interference to other stations operating on a higher frequency band
B-003-13-02:
What may your FM hand-held or mobile transceiver do if you shout into its microphone?
It may cause interference to other stations operating near its frequency
It may cause digital interference to computer equipment
It may cause atmospheric interference in the air around the antenna
It may cause interference to other stations operating on a higher frequency band
B-003-13-03:
What can you do if you are told your FM hand-held or mobile transceiver is overdeviating?
Talk farther away from the microphone
Talk louder into the microphone
Let the transceiver cool off
Change to a higher power level
B-003-13-04:
What kind of emission would your FM transmitter produce if its microphone failed to work?
An unmodulated carrier
A frequency-modulated carrier
An amplitude-modulated carrier
A phase-modulated carrier
B-003-13-05:
Why is FM voice best for local VHF/UHF radio communications?
It has high-fidelity audio which can be understood even when the signal is somewhat weak
The carrier is not detectable
It is more resistant to distortion caused by reflected signals
Its RF carrier stays on frequency better than the AM modes
B-003-13-06:
What is the usual bandwidth of a frequency-modulated amateur signal?
Between 10 and 20 kHz
Less than 5 kHz
Between 5 and 10 kHz
Greater than 20 kHz
B-003-13-07:
What is the result of overdeviation in an FM transmitter?
Out-of-channel emissions
Increased transmitter power
Increased transmitter range
Poor carrier suppression
B-003-13-08:
What emission is produced by a reactance modulator connected to an RF power amplifier?
Phase modulation
Multiplex modulation
Amplitude modulation
Pulse modulation
B-003-13-09:
Why isn't frequency modulated (FM) phone used below 29.5 MHz?
The bandwidth would exceed limits in the Regulations
The transmitter efficiency for this mode is low
Harmonics could not be attenuated to practical levels
The frequency stability would not be adequate
B-003-13-10:
You are transmitting FM on the 2 metre band. Several stations advise you that your transmission is distorted. A quick check with a frequency counter tells you that the transmitter is on the proper frequency. Which of the following is the most probable cause of the distortion?
The frequency deviation of your transmitter is set too high
The power supply output voltage is low
The repeater is reversing your sidebands
The frequency counter is giving an incorrect reading and you are indeed off frequency
B-003-13-11:
FM receivers perform in an unusual manner when two or more stations are present. The loudest signal, even though it is only two or three times as loud as the other signals, will be the only transmission demodulated. This is called:
capture effect
attach effect
interference effect
surrender effect
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● = Review
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● = Incorrect answer
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