PCM编码

编码过程：符号位，段落码，段内码。符号位简单，段内码转为bin就可以
段内码下图就自己看看就好

![段内码对照表](https://img-blog.csdnimg.cn/20200813143627759.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzU1Nzk0Nw==,size_16,color_FFFFFF,t_70#pic_center)

import numpy as np

def PCM_encode(x):
#输入全部得是int项的list，没有做错误处理
    x = list(x)
    n = len(x)

    for i in range(n):
        try:
            x[i]=int(x[i])
        except:
            print("请输入数字")
            print(type(x[i]),"格式错误")
            return 0

    out = np.zeros((n, 8))
#建立输出

    for i in range(n):
        # 符号位
        if x[i] > 0:
            out[i, 0] = 1
        else:
            out[i, 0] = 0
        #段落位
        if abs(x[i]) < 16:
            out[i, 1], out[i, 2], out[i, 3], step, home = 0, 0, 0, 1, 0
        elif abs(x[i]) < 32:
            out[i, 1], out[i, 2], out[i, 3], step, home = 0, 0, 1, 1, 16
        elif abs(x[i]) < 64:
            out[i, 1], out[i, 2], out[i, 3], step, home = 0, 1, 0, 2, 32
        elif abs(x[i]) < 128:
            out[i, 1], out[i, 2], out[i, 3], step, home = 0, 1, 1, 4, 64
        elif abs(x[i]) < 256:
            out[i, 1], out[i, 2], out[i, 3], step, home = 1, 0, 0, 8, 128
        elif abs(x[i]) < 512:
            out[i, 1], out[i, 2], out[i, 3], step, home = 1, 0, 1, 16, 256
        elif abs(x[i]) < 1024:
            out[i, 1], out[i, 2], out[i, 3], step, home = 1, 1, 0, 32, 512
        else:
            out[i, 1], out[i, 2], out[i, 3], step, home = 1, 1, 1, 64, 1024

        #段内码
        sub = int(abs(x[i]) - home)
        bin_str = bin( int( sub / step) )[2:]


        res = [0,0,0,0]
        #格外重要，防止在编码过程中由于长度不够导致的-1错误
        for now in bin_str:
            res.append(now)
        mylen=len(res)
        out[i, 4], out[i, 5], out[i, 6],out[i, 7]=int(res[mylen-4]),int(res[mylen-3]),int(res[mylen-2]),int(res[mylen-1])

        #print(step, '****', sub,"***",res,'****',out[i, 4], out[i, 5], out[i, 6],out[i, 7])
        #检验是否数据位出错

    print(type(x),type(out))
    print(out)
    return out

PCM译码

import numpy as np
#解码过程
def PCM_decode(ins):
    n=len(ins)
    out = np.zeros((n, 1))

    for i in range(n):

        #符号位判断
        if ins[i][0] == 1:
            sign=1
        else:
            sign=-1
        #段落位判断
        if ins[i][1] == 0:
            if ins[i][2]==0:
                if ins[i][3]==0:
                    step,home=1,0
                else:
                    step,home=1,16
            elif ins[i][3]==0:
                step,home=2,32
            else:
                step,home=4,64
        elif ins[i][2]==0:
            if ins[i][ 3] == 0:
                step, home = 8, 128
            else:
                step, home = 16,256
        else:
            if ins[i][3] == 0:
                step, home = 32, 512
            else:
                step, home = 64,1024


        #段内码
        newcode=(ins[i][4]*8+ins[i][5]*4+ins[i][6]*2+ins[i][7])*step+home
        print(newcode)
        out[i]=newcode

    return out

注意格式，没什么难的。
以下是结果：

code=PCM_encode(["1522",25])
<class 'list'> <class 'numpy.ndarray'>
[[1. 1. 1. 1. 0. 1. 1. 1.]
 [1. 0. 0. 1. 1. 0. 0. 1.]]
 
myDecode=PCM_decode([[1,1,1,1,0,1,1,1],[0,0,0,1,1,1,1,1]])
1472
31