实现了PCM编码->基带码型转换（NRZ to HDB3）->QPSK调制->高斯信道->QPSK解调->基带码型反转换（HDB3 to NRZ）->PCM解码。同时给出了误码率曲线。-Achieve a PCM coding-> Baseband code converter (NRZ to HDB3)-> QPSK Modulation-> Gaussian channel-> QPSK demodulator-> anti-baseband conversion pattern (HDB3 to NRZ)-> PCM decoding. Also shows the BER curves.