本文介绍了利用点对点(PTP)数字通信系统模型,推导卷积编码和Viterbi译码的非线性传输函数的方法以及对Viterbi译码软判决和硬判决的性能分析。通过Matlab中的Simulink仿真模块,对系统模型进行了建模,其仿真结果表明,增大卷积编码和Viterbi译码的约束长度可以提高误码性能。最后,得到了Viterbi译码在软判决和硬判决条件下的误码曲线。 This paper introduces the method of using the point-to-point (PTP) digital communication system model to derive the nonlinear transfer function of convolutional coding and Viterbi decoding, as well as the performance analysis of soft-decision and hard-decision of Viterbi decoding. The system model is modeled by the Simulink simulation module in Matlab. The simulation results show that increasing the constraint length of convolutional coding and Viterbi decoding can improve the error performance. Finally, the BER curves of Viterbi decoding under soft decision and hard decision are obtained.