中文说明：用（7,4）线性分组码为例，采用和积算法进行译码。和BPSK译码进行对比，得出结论。用和积算法进行译码，在信噪比较低的情况下，和积算法译码不如未编码译码。当信噪比超过6dB左右时，译码效果好于未编码译码
English Description：
(7,4) linear block codes, for example, the sum-product algorithm for decoding. And comparing the decoding of BPSK and draw conclusions. Sum-product algorithm for decoding, in circumstances of low Snr, sum-product decoding than not encoding and decoding algorithm. When the signal to noise ratio than 6dB is about decoding is better than no encoding and decoding