A-006-02: Oscillators, mixers, tuning
A-006-02-01:
The mixer stage of a superheterodyne receiver is used to:
change the frequency of the incoming signal to that of the IF
allow a number of IF frequencies to be used
remove image signals from the receiver
produce an audio frequency for the speaker
A-006-02-02:
A superheterodyne receiver designed for SSB reception must have a beat-frequency oscillator (BFO) because:
the suppressed carrier must be replaced for detection
it phases out the unwanted sideband signal
it reduces the pass-band of the IF stages
it beats with the receiver carrier to produce the missing sideband
A-006-02-03:
The first mixer in the receiver mixes the incoming signal with the local oscillator to produce:
an intermediate frequency
an audio frequency
a radio frequency
a high frequency oscillator (HFO) frequency
A-006-02-04:
If the incoming signal to the mixer is 3 600 kHz and the first IF is 9 MHz, at which one of the following frequencies would the high frequency oscillator (HFO) operate?
5 400 kHz
3 400 kHz
10 600 kHz
21 600 kHz
A-006-02-05:
The BFO is off-set slightly (500 - 1 500 Hz) from the incoming signal to the detector. This is required:
to beat with the incoming signal
to pass the signal without interruption
to provide additional amplification
to protect the incoming signal from interference
A-006-02-06:
It is very important that the oscillators contained in a superheterodyne receiver are:
stable and spectrally pure
sensitive and selective
stable and sensitive
selective and spectrally pure
A-006-02-07:
In a superhetrodyne receiver, a stage before the IF amplifier has a variable capacitor in parallel with a trimmer capacitor and an inductance. The variable capacitor is for:
tuning of the high-frequency oscillator (HFO)
tuning both the antenna and the BFO
tuning of the beat-frequency oscillator (BFO)
tuning both the antenna and the HFO
A-006-02-08:
In a superhetrodyne receiver without an RF amplifier, the input to the mixer stage has a variable capacitor in parallel with an inductance. The variable capacitor is for:
tuning of the antenna
tuning both the antenna and the BFO
tuning the beat-frequency oscillator (BFO)
tuning both the antenna and the HFO
A-006-02-09:
What receiver stage combines a 14.25-MHz input signal with a 13.795-MHz oscillator signal to produce a 455-kHz intermediate frequency (IF) signal?
Mixer
BFO
VFO
Multiplier
A-006-02-10:
Which two stages in a superheterodyne receiver have input tuned circuits tuned to the same frequency?
RF and first mixer
IF and local oscillator
RF and IF
RF and local oscillator
A-006-02-11:
The mixer stage of a superheterodyne receiver:
produces an intermediate frequency
produces spurious signals
acts as a buffer stage
demodulates SSB signals
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