From 05c2027520ad34a650b8e6b288b088036b90a877 Mon Sep 17 00:00:00 2001
From: iridiumR <i@iridium.cyou>
Date: Sat, 26 Nov 2022 17:24:08 +0800
Subject: [PATCH] feat(matlab): comm lab 5

---
 Matlab/comm/lab5_0.m | 60 ++++++++++++++++----------------------------
 1 file changed, 22 insertions(+), 38 deletions(-)

diff --git a/Matlab/comm/lab5_0.m b/Matlab/comm/lab5_0.m
index f71a8e1..324e20a 100644
--- a/Matlab/comm/lab5_0.m
+++ b/Matlab/comm/lab5_0.m
@@ -1,23 +1,23 @@
 clc
+clear
 %================================================
 %已知抽样值以△为单位
 %================================================
-x = 2047                        %抽样值/量化单位△
-pcmcode = pcmEnCode(x)                %调用pcmCode()函数实现PCM编码
-amp = pcmDeCode(pcmcode)            %调用pcmDecode()函数实现PCM译码
-amp = pcmDecode(pcmcode)
-%qerror = x-amp                      %求量化误差
+x = 500
+pcmcode = pcmEnCode(x)
+amp = pcmDeCode(pcmcode)
+qerror = x-amp
 %================================================
 %已知抽样值为实际电压值，则需先转换为以△为单位
 %================================================
-% M = 5;                              %设置量化范围 -5~+5
-% delta = M/2^11;                     %求量化单位△
-% y = +2.5                              %设置抽样值/V
-% y0 = round(y/delta)                 %将抽样值转换为以△为单位
-% pcmcode = pcmCode(y0)                %PCM编码
-% amp=pcmDecode(pcmcode);             %PCM译码
-% amp = amp*delta                     %转换为实际电压值
-% qerror=y-amp                       %求量化误差
+M = 5
+d = M/2^11;
+x = 2.5
+x0 = round(x/d)
+pcmcode = pcmEnCode(x0);
+amp0=pcmDeCode(pcmcode);
+amp0 = amp0*d
+qerror=x-amp0
 
 
 function pcmcode = pcmEnCode(s)
@@ -27,7 +27,7 @@ function pcmcode = pcmEnCode(s)
     if s>0 
         pcm=pcm+bitshift(1,7);
     else
-        s=abs(s)
+        s=abs(s);
     end
     for i = 0:7
         if s < start_t(i+2)
@@ -43,30 +43,14 @@ function amp = pcmDeCode(pcmcode)
     start_t=[0,2.^(4:11)];
     width_t=[1,1,2,4,8,16,32,64];
     code=bin2dec(pcmcode);
-    isNeg=0;
-    if code < 128
-        isNeg=1;
-    k=bitshift(bitand(code,0b01111111),-4);
-    amp=start_t(k+1) ...
-       + double(mod(bitand(code,0b01111111),16)) ...
-       * width_t(k+1);
-    if isNeg=1 amp=-amp;end
-end
-
-%PCM译码函数
-function amp = pcmDecode(pcmcode)
-    code_table=[0,2.^(4:11)];           %段落起始电平表
-    delta=[1,1,2,4,8,16,32,64];         %段内量化间隔表
-    codeDec=bin2dec(pcmcode);           %二进制编码字符串转换为十进制数值
-    ucode=bitand(codeDec,0b01111111);   %屏蔽极性位
-    k=bitshift(ucode,-4);               %右移4位，提取段落码
-    x0=code_table(k+1);                 %查表求段落起始电平
-    m=bitand(ucode,0b00001111);         %提取段内码
-    x1=double(m)*delta(k+1);            %求段内量化电平
-    dV=x0+x1+delta(k+1)/2;              %译码输出电平 
-    if codeDec<=128                     %处理极性
-        amp=-dV;
+    ucode=bitand(code,0b01111111);
+    k=bitshift(ucode,-4);
+    m=bitand(ucode,0b00001111);
+    amp=start_t(k+1)+double(m)*width_t(k+1)+width_t(k+1)/2;
+    if code<=128 
+        amp=-amp;
     else 
-        amp=dV;
+        amp=amp;
     end
 end
+