A common encoding technique in which each of the two modulated streams is a BPSK signal at half the data rate of the original bit stream is ________.The combined signals have a symbol rate that is half the input bit rate.
A)MPSK
B)MFSK
C)QPSK
D)QAM

Question

Quizplus · Accepted Answer

The technique described in the question is called Quadrature Phase Shift Keying (QPSK). QPSK is a form of phase modulation that can be thought of as two separate BPSK signals sent at the same time, but with their carrier waves out of phase with each other by 90 degrees (i.e., they are in quadrature). Each of the two modulated streams carries half of the bits of the original bit stream, and the combined signals have a symbol rate that is half the input bit rate. Therefore, the correct answer is C) QPSK.

A Common Encoding Technique in Which Each of the Two