Microwave Devices and Circuits MCQs

Question 1

Show which of the following statement about the amplitude limiter is untrue?

Accepted Answer

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

Answer

when th input increases past the threshold of limiting, the gain decreases to keep the output constant

Answer

the output must be tuned

Answer

leak-type bias must be used

Question 2

In a ratio detector

Accepted Answer

the linearity is worse than in a phase discriminator

Answer

stabilization against signal strength variations is provided

Answer

the output is twice that obtainable from a similar phase discriminstor

Answer

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

Question 3

Indicate the false statement :Fourier analysis shows that a sawtooth wave consists of

Accepted Answer

fundamental and harmonic sine waves whose amplitude decreases with the harmonic number

Answer

fundamental and sub-harmonic sin waves

Answer

a fundamental sine wave and an infinite number of harmonics

Question 4

When electromagnetic waves are reflected at an angle from a wall, their wavelength along the wall is

Accepted Answer

greater than in the actual direction of propagation

Answer

the same as in free space

Answer

the same as the wavelength perpendicular to the wall

Answer

shortended because of the Doppler effect

Question 5

The Hartley law states that

Accepted Answer

the maximum rate of information transmission depends on the channel bandwith

Answer

the maximum rate of information depends on the depth of modulation

Answer

redundancy is essential

Answer

only binary code may be used

Question 6

A duplexer is used

Accepted Answer

to allow the one antenna to be used for reception or transmission without mutual interference

Answer

to couple two different antennas to transmitter without utual interference

Answer

to prevent interference between two antennas when they are connected to a receiver

Answer

to increase the speed of the pulses in pulsed radar

Question 7

Indicate the false statement regarding the advantages of SSB over doubleside-band, full-carrier AM

Accepted Answer

transmitter circuit must be more stable giving better reception

Answer

more channel space is available

Answer

the signal is more noise-resistant

Answer

much less power is required for the same signal strength

Question 8

Which of the following frequency bands fall under microwave frequency?

Accepted Answer

UHF, SHF and EHF

Answer

UHF and SHF

Answer

SHF and EHF

Answer

VLF, LF and MF

Question 9

The wavelength of microwaves at 100 GHz will be

Accepted Answer

0.3 cm

Answer

3 cm

Answer

0.03 cm