Deck 6: Receivers

Question 1

Which of the following is responsible for the image frequency rejection characteristics of the receiver?
A.Auxiliary AGC diode
B.Automatic frequency control (AFC)
C.Preselector
D.Discriminator

Answer 1

Preselector

Question 2

What is the purpose of the detector?
A.To recover the low-frequency intelligence or baseband signal from the much higher intermediate- or radio-frequency carrier.
B.To remove any residual amplitude modulation and the amplitude variations resulting from noise.
C.To make an economical LC oscillator at 100 MHz with sufficient frequency stability.
D.To recreate the carrier.

Answer 2

To recover the low-frequency intelligence or baseband signal from the much higher intermediate- or radio-frequency carrier.

Question 3

A __________ function in an FM receiver is to remove any residual amplitude modulation and the amplitude variations resulting from noise.
A.limiter
B.discrete analog component
C.local oscillator
D.discriminator

Answer 3

l imiter

Question 4

What does it mean if two signals are said to be in quadrature?
A.At a 90° angle
B.Output is zero with no modulation
C.One-half that for the Foster-Seeley circuit
D.Phase-shift detection arises quite often

Question 5

What is one of the great advantages of the diode (envelope)detector?
A.75% efficiency obtainable
B.Distortion increases as amplitude decreases
C.Can handle low power signals
D.Simplicity

Question 6

What is the name for the additional signal used to transmit music programming that is usually commercial-free but paid for by subscription?
A.PLL FM demodulator
B.Subsidiary communication authorization
C.Quadrature detector
D.Foster-Seeley discriminator

Question 7

Demodulation of the SSB signal requires a beat-frequency oscillator and a(n)_____________.
A.intelligence signal
B.mixer stage
C.diode detector
D.sideband receiver

Question 8

What is created in a receiver with reception of electromagnetic interference (EMI)?
A.Undesired amplitude modulation
B.Variable sensitivity
C.Diode resistance
D.Distorted, unintelligible output

Question 9

A receiver's ________ is the minimum input signal,expressed as a voltage,required to produce a specified output.
A.selectivity
B.intelligence
C.sensitivity
D.amplification

Question 10

Which of the following quantifies how the received signal is impaired by both noise voltages and distortion components?
A.SINAD
B.Noise floor
C.Dynamic range
D.Squelch

Question 11

The ___________ of an amplifier or receiver is the input power range over which it provides a useful output.
A.simple automatic gain control (AGC)
B.quadrature detector
C.Foster-Seeley discriminator circuit
D.dynamic range

Question 12

What is the key to the superior selectivity of the superheterodyne receiver?
A.Constant bandwidth
B.Low frequencies
C.Image frequency
D.Intelligence detection

Question 13

What is the factor most directly limiting sensitivity?
A.Bandwidth
B.Carrier frequency
C.Sufficient amplification
D.Noise

Question 14

What type of detector is a circuit designed to respond only to frequency changes of the input signal?
A.Slope
B.Ratio
C.Quadrature
D.Synchronous

Question 15

What is one advantage of the direct-conversion architecture?
A.Superior intermodulation performance
B.Simplicity
C.Superior cross-modulation
D.Fully implemented with discrete components

Question 16

_______________ is the process of stepping down the RF signal to a first,relatively high IF frequency and then mixing down again to a second,lower,final IF frequency.
A.Deemphasising
B.Double conversion
C.Up-conversion
D.Suppression

Question 17

___________ are used in the vast majority of AM detection schemes where the carrier and sidebands are present.
A.Foster-Seeley discriminators
B.Ratio detectors
C.Diode detectors
D.FM discriminators

Question 18

Why is amplification with an antenna?
A.Low noise
B.Small signal
C.Small bandwidth
D.Variable-selectivity problems

Question 19

A receiver's _________ is the extent to which a receiver is capable of differentiating between the desired signal and unwanted radio signals and noise.
A.sensitivity
B.bandwidth
C.tuning range
D.selectivity

Question 20

What principle does the synchronous detector rely on?
A.Phase-locked loop
B.Square law
C.Inverse relationship
D.Superheterodyne

Question 21

An essential function within any receiver is some form of ____________.
A.system noise ratio
B.sensitivity
C.dynamic range
D.automatic gain control

Question 22

What technique is used to obtain variable selectivity?
A.Auxiliary AGC
B.Variable bandwidth tuning (VBT)
C.Delayed AGC
D.Electromagnetic interference (EMI)

Question 23

Poor __________ causes problems,such as undesired interference and distortion,when a strong signal is received.
A.RF generator output
B.dynamic range
C.ambient temperature
D.carrier frequency

Question 24

Which of the following silences the audio amplifier stages until a carrier is detected?
A.TRF
B.S meter
C.Conversion oscillator
D.Squelch circuits

Question 25

Many communications receivers are equipped with a(n)____________ that provides a visual indication of received signal strength.
A.S meter
B.squelch circuit
C.noise limiter
D.bandpass filter