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GATE EC 2022: Communication System Quiz 1 (App update required to attempt this test)

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Question 1

An information carrying signal g(t) band limited to W Hz is received after passing through a distoring channel H(f)


The magnitude of the received signal when sampled at TS = 3 sec is_______

Question 2

A joint sample space for 2 random variable X and Y has four elements (1, 1), (2, 2), (3, 3), (4, 4) probability of these elements are 0.1, 0.2, 0.3, 0.4 respectively.

The probability of event (x ≤ 2.5, y ≤ 5) will be

Question 3

Consider the Armstrong FM modulator shown in the figure below


The narrow band FM signal has maximum angular deviation of 0.10 radians in order to keep distortion under control. The message signal m(t) has a bandwidth of 15 KHz, the oscillator frequency is 100 KHz and the mixer circuit is used for the up-conversion. If the wideband FM signal s(t) has a carrier frequency of fc = 104 MHz and a maximum frequency deviation of Δfmax = 75 KHz then the multiplication factor n2 will be

Question 4

A carrier wave is frequency modulated using a sinusoidal signal of frequency fm and amplitude Am. In a certain experiment conducted with fm = 1kHz and increasing Am (Starting from 0 volts), it is found that the carrier component of the FM signal is reduced to zero for the first time when Am = 2 volts. What is the frequency sensitivity of the modulator?

Question 5

An analog signal, which is band limited to 10 KHz, is sampled at a rate of fs and the samples are applied to a 32-level PCM system. The resultant bits are separated by using a raised cosine filter with roll-off factor of 0.60 and transmitted through a baseband channel. If the channel bandwidth is 100 kHz, then the maximum allowed sampling rate (fs) for |S| free transmission, will be _______ kHz.

Question 6

If two independent random variables X and Y have variance 20 and 5 respectively. If two new random variables U = X + Y and V = X – Y are defined, then the value of correlation coefficient
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May 7ESE & GATE EC