中文说明：应用背景本编码是将四状态网格编码8PSK调制误比特率、未编码QPSK调制误比特率、四状态网格编码8PSK调制理论误比特率进行比较，从而可以得出在输入相同的信噪比下，四状态网格编码8PSK调制比未编码QPSK调制能获得更多的编码增益，从而在实际的工程中，可以应用这种思想，获得更多的编码增益。关键技术四状态网格编码8PSK调制相比较于未编码QPSK调制，将2bit四状态的信号进行卷积编码成3bit数据，然后采用8psk调制进行映射，从而在维特比进行译码解调时获得更大的欧式距离，解调采用的基于欧氏距离的维特比译码，根据相加得到的最小值获得最佳的路径，得到译码之后的2bit数据。
English Description：
Application backgroundThis encoding is the bit error rates of four state trellis coded 8PSK modulation, uncoded QPSK modulation bit error rate, four state trellis coded 8PSK modulation theoretical bit error rate were compared, which can be obtained in the same input signal to noise ratio, four state trellis coded 8PSK modulation than uncoded QPSK modulation can obtain more coding gain, thus in practical engineering can using this idea, obtain more coding gain.Key TechnologyFour state trellis coded 8PSK modulation compared to uncoded QPSK modulation, 2bit four state signals were convolutional coding 3bit data, then using 8PSK modulation mapping, resulting in Viterbi decoding and demodulation gain greater Euclidean distance and the demodulation of the Viterbi decoding based on the Euclidean distance, according to the summed to obtain the minimum value for the best path and get the decoding after 2bit data.