Deck 4: Electronics and Telecommunications

Question 1

In a TV receiver antenna the length of reflector rod.

A)is the same as that of dipole
B)is less than that of dipole
C)is more than that of dipole
D)may be equal, more or less than that of dipole

Answer 1

is more than that of dipole

Question 2

The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?

A)gets halved
B)gets doubled
C)gets increased by 50 percent
D)remains unchanged

Answer 2

gets increased by 50 percent

Question 3

For AM receivers the standard IF frequency is

A)106 khz
B)455 khz
C)1.07 mhz
D)10.7 mhz

Answer 3

455 khz

Question 4

For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as

A)2e
B)3e
C)4e
D)6e

Question 5

In TV systems, equalising pulses are sent during

A)horizontal blanking
B)vertical blanking
C)serrations
D)horizontal retrace

Question 6

A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is

A)16
B)15
C)8
D)1

Question 7

The main function of a balanced modulator is to

A)produce balanced modulation of a carrier wave
B)produce 100% modulation
C)suppress carrier signal in order to create a single-sideband or double sideband
D)limit noise picked by a receiver