The bandwidth required for QPSK modulated channel is

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ISRO VSSC Technical Assistant Electronics 2018 Official Paper
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  1. half of the bandwidth of BPSK
  2. twice of the bandwidth of BPSK
  3. equal to BPSK
  4. equal to FSK

Answer (Detailed Solution Below)

Option 1 : half of the bandwidth of BPSK
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Detailed Solution

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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).

\(Bandwidth = \frac{{2{R_b}}}{{{{\log }_2}M}}\)

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.

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