Top Communication Systems Questions

A cordless telephone using separate frequencies for transmission in base and portable units is known as

• duplex arrangement

• half duplex arrangement

• either (a) or (b)

• neither (a) nor (b)

For attenuation of high frequencies we should use

• shunt capacitance

• series capacitance

• inductance

• resistance

A modem is classified as low speed if data rate handled is

• upto 100 bps

• upto 250 bps

• upto 400 bps

• upto 600 bps

VSB modulation is preferred in TV because

• it reduces the bandwidth requirement to half

• it avoids phase distortion at low frequencies

• it results in better reception

• none of the above

A woofer should be fed from the input through a

• low pass filter

• high pass filter

• band pass filter

• band stop filter

Which of the following is an indirect way of generating FM?

• Armstrong modulator

• Varactor diode modulator

• Reactance FET modulator

• Reactance bipolar transistor

When the length of antenna is a whole wavelength

• the radiation at right angles is zero

• the radiation at right angles is maximum

• the radiation is zero in all directions

• the radiation is maximum in all directions

Circular polarization

• is useful in reducing depolarization effect on received wave

• involves critical alignment of transmitting and receiving antenna

• is useful in discrimination between reception of adjacent beams

• none of the above

An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.

• 102.3

• 113

• 70.2

• 80.9

For telegraphy the most commonly used modulation system is

• FSK

• two tone modulation

• PCM

• single tone modulation