Digital Communication System MCQs

inn is sin(0 / 2) q-4.0 0

If R(T) is the autocorrelation function of a real, wide-sense stationary random process, then which of the following is NOT true? x(t) ? 5 (sin 2n 1000t )3 + 7 ( nt sin In 1000t )3 nt would be (a) 2 x 103 (c) 6 x 103 A(t) Same Y2(t)

The 3-dB bandwidth of the low-pass signal e-t u(t), where u(t) is unit step function, is given by

In the following scheme, if the spectrum M(f) of m(t) is as shown, then the spectrum Y(/) of y(t) will be-aL The ratio of the average energy of Constellation 1 to the average energy of Constellation 2 is

If these constellations are used for digital communications over an AWGN channel, then which of the following statements is true?

An input to a 6-level quantizer has the probability density functionf(x) as shown in the figure 11.12. Decision boundaries of the quantizer are chosen so as to maximize the entropy of the quantizer output. If is given that 3 consecutive decision boundaries are '-1', '0' and '1'. L The values of a and b are

Assuming that the reconstruction levels of the quantizer are the midpoints of the decision boundaries, the ratio of signal power to quantization noise power is

The voltage Vo is

If a zero-crossing detector used in this system indicates a time of 510 1.1s, the state received would be 1/0.