Digital Communication - Study Mode
[#181] Increased pulse width in the flat top sampling, leads to
Correct Answer
(A) Attenuation of high frequencies in reproduction
[#182] A video transmission system transmits 625 picture frames per second. Each frame consists of a 400 × 400 pixel grid with 64 intensity levels per pixel. The data rate of the system is
Correct Answer
(D) 6.4 Gbps
[#183] The raised cosine pulse p(t) is used for zero ISI in digital communications. The expression for p(t) with unity roll-off factor is given by $$pleft( t
ight) = frac{{sin 4pi omega t}}{{4pi omega tleft( {1 - 16{omega ^2}{t^2}}
ight)}}.$$ xa0 xa0 The value of p(t) at $$t = frac{1}{{4omega }}$$xa0 is
Correct Answer
(C) 0.5
[#184] A sinusoidal signal of 2 kHz frequency is applied to a delta modulator. The sampling rate and step-size Δ of the delta modulator are 20,000 samples per second and 0.1 V, respectively. To prevent slope overload, the maximum amplitude of the sinusoidal signal (in Volts) is
Correct Answer
(A) $$frac{1}{{2pi }}$$
[#185] Coherent orthogonal binary FSK modulation is used to transmit two equiprobable symbol waveforms s 1 (t) = αcos2πf 1 t & s 2 (t) = αcos2πf 2 t 1 where α = 4 mV. Assume an AWGN channel with two-sided noise power spectral density $$frac{{{N_0}}}{2} = 0.5 imes {10^{ - 12}}W/Hz.$$ xa0 xa0 Using an optimal receiver and the relation $$Qleft( v
ight) = frac{1}{{sqrt {2pi } }}intlimits_v^infty {{ heta ^{frac{{{u^2}}}{2}}}du,} $$ xa0 xa0 the bit error probability for a data rate of 500 kbps is
Correct Answer
(C) Q(4)