ENGINEERING MECHANICS QUIZ

The local oscillator of a broadcast receiver is tuned to a frequency higher than the incoming frequency

To help the image frequency rejection

Because otherwise an intermediate frequency could not be produced

To allow adequate frequency coverage without switching

To permit easier tracking

TRUE ANSWER : ?
YOUR ANSWER : ?

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

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

The output must be tuned

Leak-type bias must be used

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

TRUE ANSWER : ?
YOUR ANSWER : ?

When a receiver has good blocking performance, this means that

It is unaffected by AGC derived from nearby transmissions

It does not suffer from double-spotting

Its detector suffers from burnout

Its image frequency rejection is poor

TRUE ANSWER : ?
YOUR ANSWER : ?

A superheterodyne receiver with an IF of 450 kHz is tuned to a signal at 1200 kHz. The image frequency is

2100 kHz

1650 kHz

750 kHz

900 kHz

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

Provide improved tracking

Permit better adjacent-channel rejection

Increase the tuning range of the receiver

TRUE ANSWER : ?
YOUR ANSWER : ?

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

It is relatively free of spurious frequency

Its frequency stability is better

It does not require crystal oscillator

It is a simpler piece of equipment

TRUE ANSWER : ?
YOUR ANSWER : ?

Indicate which of the following statements about the advantages of the phase discriminator over the slope detector is false:

Fewer tuned circuits

Better linearity

Much easier alignment

Greater limiting

TRUE ANSWER : ?
YOUR ANSWER : ?

A receiver has poor IF selectivity. It will therefore also have poor

Diversion reception

Double-spotting

Sensitivity

Blocking

TRUE ANSWER : ?
YOUR ANSWER : ?

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

Diagonal clipping

Poor AGC operation

Negative-peak clipping

Poor AF response

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YOUR ANSWER : ?

One of the following cannot be used to demodulate SSB:

Product detector

Bipolar transistor balanced modulator

Diode Balance modulator

Complete phase-shift generator

TRUE ANSWER : ?
YOUR ANSWER : ?