In DPSK system, input signal is differentially encoded and then

in-dpsk-system-input-signal-is-differentially-encoded-and-then

In DPSK system, input signal is differentially encoded and then modulated using a ________ modulator.

A. Amplitude

B. Frequency

C. BPSK

D. QPSK

The question was posed to me in an internship interview.

My question comes from Linear Modulation Techniques in division Modulation Techniques for Mobile Radio of Wireless/Mobile

Correct answer is C. BPSK

The best explanation: In DPSK system, input binary sequence is first differentially encoded and then modulated using a BPSK modulator. The differentially encoded sequence is generated from input binary sequence by complimenting their modulo-2 sum.