The bandwidth required for QPSK modulated channel is

Question

Question

This question was previously asked in

ISRO VSSC Technical Assistant Electronics 2018 Official Paper

Answer 1

Concept:

BPSK transfers one bit per symbol. It either transmits 0 or 1 at a time.

QPSK is a modulation scheme that allows one symbol to transfer two bits of data. There are four possible two-bit numbers (00, 01, 10, 11).

$B a n d w i d t h = \frac{2 R_{b}}{\log_{2} M}$

Calculation:

For BPSK M = 2 bandwidth = 2Rb

For QPSK M = 4 bandwidth = Rb

The bandwidth required for QPSK modulated channel is half of the bandwidth of BPSK.