Digital Communication - Study Mode

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[#71] In a binary PCM system, the maximum tolerable error is sample amplitudes is 0.5% of the peak input signal amplitude. The input signal bandwidth is 5 MHz. The minimum rate of transmission of the PCM coded bits is:

(A) 70 Mbits/sec

(B) 80 Mbits/sec

(C) 90 Mbits/sec

(D) 100 Mbits/sec

Correct Answer

(B) 80 Mbits/sec

[#72] The bit rate of a digital communication system is 34 Mbit/s. The modulation scheme is QPSK. The baud rate of the system is

(A) 68 Mbit/s

(B) 34 Mbit/s

(C) 17 Mbit/s

(D) 8.5 Mbit/s

Correct Answer

(C) 17 Mbit/s

[#73] What is the process of utilizing one data link for transmission of a group of variable known as?

(A) Encoding

(B) Decoding

(C) Demultiplexing

(D) Multiplexing

Correct Answer

(D) Multiplexing

[#74] In a single error correcting Hamming code, the number of message bits in a block is 26. The number of check bits in the block would be

(A) 3

(B) 4

(C) 5

(D) 7

Correct Answer

(C) 5

[#75] A satellite system employs QPSK modulation with 40% excess bandwidth per carrier including guard band. The voice channels use 64 kbps PCM coding. The number of channels supported by 36 MHz bandwidth of the transponder in bandwidth limited case will be

(A) 1000

(B) 800

(C) 900

(D) 600

Correct Answer

(B) 800