DPSK-Differential Phase Shift Keying Basics
This page describes DPSK basics and DPSK modulation and demodulation.
DPSK stands for Differential Phase Shift Keying. It is the version of BPSK. In DPSK, there is no absolute carrier phase reference, instead transmitted signal itself used as phase reference.
In DPSK demodulation, phase of the received bit is compared with phase of the previous bit.
Figures show the process of DPSK modulation and DPSK demodulation. In DPSK modulation, serial binary data passes through X-NOR gate and output is fed back via 1 bit delay. and the resulting bit stream is applied to the balanced modulator to produce DPSK signal.
In DPSK demodulator DPSK signal is passed to the balanced modulator and 1 bit delay circuit. The resulting signal is passed to the LPF which produces binary data. This is passed to comparator circuit(or schmitt trigger circuit) to produce clean and high speed binary levels.