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The modulation system which is commonly used in telegraphic communication is
(A) pulse-code modulation (B) two-tone modulation
(C) frequency-shift keying (D) single-tone modulation

The code which is used for parity checks is

(A) Gray (B) ASCII

(C) EBCDIC (D) Baudot

The transmission rate of data in a modem is measured in

(A) bytes per second (B) Gigahertz

(C) bits per second (D) word per minute

The On-Off keying method of data transmission is otherwise known as

(A) ASK (B) FSK

(C) PSK (D) BPSK

The type of microphone used in telephone is

(A) Condenser microphone (B) Ribbon microphone
(C) Peizo electric (D) Carbon microphone

The type of noise which is having greater impact at high frequencies is
(A) random noise (B) Johnson noise
(C) transit-time noise (D) shot noise

Which of the following modulation system is the most noise resistant one?

(A) PWM (B) Delta

(C) PCM (D) Differential PCM

The reason for Rayleigh scattering loss in optical fibre is

(A) bending of fibre (B) structural fault in glass
(C) impurities present (D) due to dispersion

Quantizing noise occurs in
(A) amplitude modulation (B) frequency modulation
(C) pulse-code modulation (D) pulse-width modulation

The main disadvantage of CW Doppler radar is
(A) does not give target range

(B) does not give target position

(C) does not give target velocity

(D) does not give angular position of target

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