多相制信号常用的产生方法有:直接调相法及相位选择法。在M进制数字相位调制中，四进制绝对移相键控(4PSK，又称QPSK)用的最为广泛，下面以 四进制绝对移相键控(4PSK，又称QPSK)为例-Multi phase signal methods commonly used are: direct modulation method and phase selection method. In M band digital phase modulation, the four absolute phase shift keying (4PSK, also known as QPSK) is the most widely used, the following four absolute phase shift keying (4PSK, also known as QPSK) as an example