Digital Communication - Study Mode
[#46] In which one of the following techniques, RF binary signals are transmitted as given? 0 : $$sqrt 2 $$ p'(t)cos[ω C - (∆ω/2)]t 1 : $$sqrt 2 $$ p'(t)cos[ω C + (∆ω/2)]t
Correct Answer
(B) FSK
[#47] As practical signals are time limited, they have infinite frequency bandwidth. Sampling of such signals lead to aliasing. To avoid aliasing, an anti-aliasing filter is used
Correct Answer
(C) before the signal is sampled
[#48] In a PCM system, if we increase the quantization levels from 2 to 8, how do the relative bandwidth requirements vary?
Correct Answer
(B) Get tripled
[#49] Four signals g 1 (t), g 2 (t), g 3 (t) and g 4 (t) are to be multiplexed and transmitted g 1 (t) and g 4 (t) have a bandwidth of 4 kHz, and the remaining two signals have bandwidth of 8 kHz. Each sample requires 8 bit for encoding. What is the minimum transmission bit rate of the system?
Correct Answer
(D) 384 kbps
[#50] Consider a Binary Symmetric Channel (BBC) with probability of error being p. To transmit a bit, say 1, we transmit a sequence of three 1s. The receiver will interpret the received sequence to represent 1 if at least two bits are 1. The probability that the transmitted bit will be received in error is
Correct Answer
(A) p 3 + 3p 3 (1 - p)