Canadian Advanced Qualification Question Pool
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What are the advantages of the frequency-conversion process in a superheterodyne receiver?
Automatic soft-limiting and automatic squelching
Increased selectivity and optimal tuned circuit design
Automatic squelching and increased sensitivity
A-006-01-02
What factors should be considered when selecting an intermediate frequency?
Noise figure and distortion
Interference to other services
Cross-modulation distortion and interference
A-006-01-03
One of the greatest advantages of the double-conversion over the singleconversion receiver is that it:
is much more sensitive
suffers less from image interference
produces a louder signal at the output
A-006-01-04
In a communications receiver, a crystal filter would be located in the:
local oscillator
audio output stage
detector
A-006-01-05
A multiconversion superheterodyne receiver is more susceptible to spurious responses than a single-conversion receiver because of the:
poorer selectivity in the IF caused by the multitude of frequency changes
greater sensitivity introducing higher levels of RF to the receiver
AGC being forced to work harder
causing the stages concerned to overload
A-006-01-06
Most superheterodyne receivers operating on the HF amateur bands through to 30 MHz use a standard intermediate frequency (IF) of:
455 kHz
500 kHz
355 kHz
A-006-01-07
Which stage of a receiver has its input and output circuits tuned to the received frequency?
The audio frequency amplifier
The detector
The RF amplifier
A-006-01-08
Which stage of a superheterodyne receiver lies between a tuneable stage and a fixed tuned stage?
Intermediate frequency amplifier
Local oscillator
Mixer
A-006-01-09
A single conversion receiver with a 9 MHz IF has a local oscillator operating at 16 MHz. The frequency it is tuned to is:
21 MHz
9 MHz
7 MHz
A-006-01-10
A double conversion receiver designed for SSB reception has a beat frequency oscillator and:
two IF stages and two local oscillators
two IF stages and three local oscillators
two IF stages and one local oscillator
A-006-01-11
The advantage of a double conversion receiver over a single conversion receiver is that it:
suffers less from image interference
is a more sensitive receiver
produces a louder audio signal
A-006-02-01
The mixer stage of a superheterodyne receiver is used to:
remove image signals from the receiver
produce an audio frequency for the speaker
change the frequency of the incoming signal to that of the IF
A-006-02-02
A superheterodyne receiver designed for SSB reception must have a beatfrequency oscillator (BFO) because:
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:
a radio frequency
a high frequency oscillator (HFO) frequency
an intermediate 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?
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 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:
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 beat-frequency oscillator (BFO)
tuning both the antenna and the HFO
tuning of the high-frequency oscillator (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 the beat-frequency oscillator (BFO)
tuning both the antenna and the HFO
tuning of the antenna
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?
VFO
Multiplier
Mixer
A-006-02-10
Which two stages in a superheterodyne receiver have input tuned circuits tuned to the same frequency?
RF and IF
RF and local oscillator
RF and first mixer
A-006-02-11
The mixer stage of a superheterodyne receiver:
produces spurious signals
acts as a buffer stage
demodulates SSB signals
A-006-03-01
What is meant by the noise floor of a receiver?
The minimum level of noise that will overload the receiver RF amplifier stage
The amount of noise generated by the receiver local oscillator
The weakest signal that can be detected above the receiver internal noise
A-006-03-02
Which of the following is a purpose of the first IF amplifier stage in a receiver?
To improve selectivity
To increase dynamic response
To improve noise figure performance
A-006-03-03
How much gain should be used in the RF amplifier stage of a receiver?
Sufficient gain to allow weak signals to overcome noise generated in the first mixer stage
It depends on the amplification factor of the first IF stage
Sufficient gain to keep weak signals below the noise of the first mixer stage
A-006-03-04
What is the primary purpose of an RF amplifier in a receiver?
To develop the AGC voltage
To provide most of the receiver gain
To improve the receiver noise figure
A-006-03-05
What is the primary source of noise that can be heard in a VHF/UHF band receiver with its antenna connected?
Atmospheric noise
Receiver front-end noise
Man-made noise
A-006-03-06
What is the term used for the decibel difference (or ratio) between the largest tolerable receiver input signal (without causing audible distortion products) and the minimum discernible signal (sensitivity)?
dynamic range
stability
noise figure
A-006-03-07
The lower the receiver noise figure becomes, the greater will be the receiver's _________ :
selectivity
sensitivity
stability
A-006-03-08
The noise generated in a receiver of good design originates in the:
BFO and detector
RF amplifier and mixer
IF amplifier and detector
A-006-03-09
Why are very low noise figures relatively unimportant for a ionospheric distortion of high frequency receiver? the received signal creates high noise levels
the use of SSB and CW on the HF bands overcomes the noise
regardless of the front end, the succeeding stages when used on HF are very noisy
A-006-03-10
The term which relates specifically to the amplitude levels of multiple signals that can be accommodated during reception is called:
AGC
cross-modulation index
noise figure
A-006-03-11
Normally, front-end selectivity is provided by the resonant networks both before and after the RF stage in a superheterodyne receiver. This whole section of the receiver is often referred to as the:
preamplifier
pass-selector
preselector
A-006-04-01
What audio shaping network is added at an FM receiver to restore proportionally attenuated lower audio frequencies?
A de-emphasis network
An audio prescaler
A heterodyne suppressor
A-006-04-02
What does a product detector do?
It amplifies and narrows band-pass frequencies
It detects cross-modulation products
It mixes an incoming signal with a locally generated carrier
A-006-04-03
Distortion in a receiver that only affects strong signals usually indicates a defect in the:
AGC
AF amplifier
RF amplifier
A-006-04-04
In a superheterodyne receiver with AGC, as the strength of the signal increases, the AGC:
increases the receiver gain
distorts the signal
introduces limiting
A-006-04-05
The amplified IF signal is applied to the ____________ stage in a superheterodyne receiver:
detector
audio output
HFO
A-006-04-06
The low-level output of a detector is:
grounded via the chassis
fed directly to the speaker
applied to the RF amplifier
A-006-04-07
The overall output of an AM/CW/SSB receiver can be adjusted by means of manual controls on the receiver or by use of a circuit known as:
inverse gain control
automatic gain control
automatic load control
A-006-04-08
AGC voltage is applied to the:
RF and AF amplifiers
detector and AF amplifiers
RF and IF amplifiers
A-006-04-09
AGC is derived in a receiver from one of two circuits. Depending on the method used, it is called:
IF derived or audio derived
IF derived or RF derived
detector derived or audio derived
A-006-04-10
In a superhetrodyne receiver, the output of an oscillator is connected to a transformer. What is the function of the transformer?
It provides tuning for the output of the intermediate frequency amplifier
It provides tuning for the input of the intermediate frequency amplifier
It provides coupling between the beatfrequency oscillator and the detector
A-006-04-11
What circuit combines signals from an IF amplifier stage and a beat-frequency oscillator (BFO), to produce an audio signal?
A power supply circuit
A VFO circuit
A detector circuit
A-006-05-01
What part of a superheterodyne receiver determines the image rejection ratio of the receiver?
AGC loop
IF filter
RF amplifier
A-006-05-02
What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?
Desensitization
Squelch gain rollback
Quieting
A-006-05-03
What causes receiver desensitization?
Squelch gain adjusted too low
Strong adjacent channel signals
Audio gain adjusted too low
A-006-05-04
What is one way receiver desensitization can be reduced?
Shield the receiver from the transmitter causing the problem
Increase the receiver bandwidth
Increase the transmitter audio gain
A-006-05-05
What causes intermodulation in an electronic circuit?
Too little gain
Positive feedback
Lack of neutralization
A-006-05-06
Which of the following is an important reason for using a VHF intermediate frequency in an HF receiver?
To provide a greater tuning range
To tune out cross-modulation distortion
To prevent the generation of spurious mixer products
A-006-05-07
Intermodulation distortion is produced by:
the mixing of more than one signal in the mixer of a superheterodyne receiver
the high-voltage stages in the final amplifier of an amplitude or frequencymodulated transmitter
the mixing of more than one signal in the first or second intermediate frequency amplifiers of a receiver
A-006-05-08
Three of the following answers are direct causes of instability in a receiver. Choose the answer which is NOT a direct cause:
feedback components
temperature
dial tracking
A-006-05-09
Poor stability in a receiver usually originates in the:
local oscillator and power supply
RF amplifier
mixer
A-006-05-10
Poor dynamic range of a receiver can cause many problems when a strong signal appears within the front-end bandpass or even outside it. Which of the following is NOT caused as a direct result?
Intermodulation
Cross-modulation
Feedback
A-006-05-11
If a receiver mixes a 13.800-MHz VFO with a 14.255-MHz received signal to produce a 455-kHz intermediate frequency (IF) signal, what type of interference will a 13.345-MHz signal produce in the receiver?
Mixer interference
Image response
Local oscillator