RADIO RECEIVERS QUIZ

Show which of the following statements about the amplitude limiter is untrue:

When the input increases past the threshold of the limiting, the gain decreases to keep the output constant.

The output must be tuned

Leak-type bias must be used

The circuit is always biased in class C, by virtue of the leak-type bias.

TRUE ANSWER : ?
YOUR ANSWER : ?

In a ratio detector

the circuit is the same as in a discriminator, except that the diodes are reversed

the output is twice that obtainable from a similar phase discriminator

stabilization against signal strength variations is provided

the linearity is worse than in phase discriminator

TRUE ANSWER : ?
YOUR ANSWER : ?

The frequency generated by each decade in a direct frequency synthesizer is much higher than the frequency shown; this is done to

Reduce the spurious frequency problem

Reduce the number of decades

Increase the frequency stability of the synthesizer

Reduce the number of crystals required

TRUE ANSWER : ?
YOUR ANSWER : ?

A low ratio of the ac to the dc load impedance of a diode detector results in

Diagonal clipping

Poor AF response

Poor AGC operation

Negative-peak clipping

TRUE ANSWER : ?
YOUR ANSWER : ?

One of the following cannot be used to demodulate SSB:

Product detector

Complete phase-shift generator

Diode Balance modulator

Bipolar transistor balanced modulator

TRUE ANSWER : ?
YOUR ANSWER : ?

If a FET is used as the first AF amplifier in a transistor receiver, this will have the effect of

Reducing the effect of negative-peak clipping

Reducing the effect of noise at low modulation depths

Improving the selectivity of the receiver

Improving the effectiveness of the AGC

TRUE ANSWER : ?
YOUR ANSWER : ?

An AM receiver uses a diode detector for demodulation. This enables it satisfactorily to receive

Single-sideband, suppressed-carrier

Single-sideband, reduced-carrier

ISB

Single-sideband, full-carrier

TRUE ANSWER : ?
YOUR ANSWER : ?

The controlled oscillator synthesizer is sometimes preferred over the direct one because

It is a simpler piece of equipment

Its frequency stability is better

It is relatively free of spurious frequency

It does not require crystal oscillator

TRUE ANSWER : ?
YOUR ANSWER : ?

In a broadcast superheterodyne receiver, the

Mixer input must be tuned to the signal frequency

Local oscillator operates below the signal frequency

Local oscillator frequency is normally double the IF

RF amplifier normally works at 455 kHz above the carrier frequency

TRUE ANSWER : ?
YOUR ANSWER : ?

One of the main functions of the RF amplifier in a superheterodyne receiver is to

Improve the rejection of the image frequency

Increase the tuning range of the receiver

Permit better adjacent-channel rejection

Provide improved tracking

TRUE ANSWER : ?
YOUR ANSWER : ?

↑