无线通信qpsk调制键控移相调制（QPSK）：调制效率高，要求传送途径的信噪比低，适合卫星广播。 -The wireless communication phase shift keying modulation qpsk modulation (QPSK): high modulation efficiency of the transmission path low SNR required for satellite broadcasting.

Complex modulation coherent pulse train signal, There are reference Oh, SNR largest independent component analysis algorithm.