3-F-049: Audio & Squelch Circuits
3-49F1:
What is the digital signal processing term for noise subtraction circuitry?
Adaptive filtering and autocorrelation.
Noise blanking.
Noise limiting.
Auto squelch noise reduction.
3-49F2:
What is the purpose of de-emphasis in the receiver audio stage?
When coupled with the transmitter pre-emphasis, flat audio and noise reduction is received.
When coupled with the transmitter pre-emphasis, flat audio is achieved.
No purpose is achieved.
To conserve bandwidth by squelching no-audio periods in the transmission.
3-49F3:
What makes a Digital Coded Squelch work?
Digital codes.
Noise.
Tones.
Absence of noise.
3-49F4:
What causes a squelch circuit to function?
Presence of noise.
Absence of noise.
Received tones.
Received digital codes.
3-49F5:
What makes a CTCSS squelch work?
Tones.
Noise.
Absence of noise.
Digital codes.
3-49F6:
What radio circuit samples analog signals, records and processes them as numbers, then converts them back to analog signals?
The digital signal processing circuit.
The pre-emphasis audio stage.
The squelch gate circuit.
The voltage controlled oscillator circuit.
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