正交相移键控（Quadrature Phase Shift Keyin，QPSK）是一种数字调制方式。它分为绝对相移和相对相移两种。由于绝对相移方式存在相位模糊问题，所以在实际中主要采用相对移相方式DQPSK。目前已经广泛应用于无线通信中，成为现代通信中一种十分重要的调制解调方式。(Quadrature phase shift keying (quadrature phase shift keyin, QPSK) is a digital modulation. It is divided into absolute and relative phase shift of the phase shift of two. Because of the absolute phase shift way of phase ambiguity, so in practice mainly uses the relative phase shift dqpsk. has been widely used in wireless communication, a a very important way of modulation and demodulation in modern communication.)