echo off
clear,clc

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% SNR_Max = 12;
Fc = 10000; 
Fs1 = 15000;
Fs = Fs1;
t = (0:1/Fs:5/Fc-1/Fs);   % column vector with all the time samples
y = cos(2*pi*Fc*t)+rand(1,length(t));
Y=abs(fftshift(fft(y)));
N=length(t);
f=(0:N-1)/N*Fs-Fs/2;
subplot(212);plot(f,Y/N)
title('原始信號頻譜')
subplot(211);plot(t,y)
title('原始信號(采樣率Fs<2Fm)')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% SNR_Max = 12;
clear,clc
Fc = 10000; 
Fs2 = 100000;
Fs = Fs2;
t = (0:1/Fs:5/Fc-1/Fs);   % column vector with all the time samples
y = cos(2*pi*Fc*t)+rand(1,length(t));
Y=abs(fftshift(fft(y)));
N=length(t);
f=(0:N-1)/N*Fs-Fs/2;
figure
subplot(212);plot(f,Y/N)
title('原始信號頻譜')
subplot(211);plot(t,y)
title('原始信號(采樣率Fs>2Fm)')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

in = y;
Note=[32 64 128];
for i1=1:length(Note)
%     %%%%%%%%%%%%%%%%%%%%分析信噪比對量化誤差的影響%%%%%
%     if i1==3
%         snr_dB=0:2:12;
%         for i2=1:length(snr_dB);
%             snr = 10^(snr_dB(i1)/10);   %SNR
%             in=in+sqrt(1/snr)*rand(1,N);
%             out1=compand(in, 87.6, 1, 'A/compressor'); %A律壓縮
%             [out_,code]=u_pcm(out1, Note(i1));  %線性編碼
%             out21=compand(out_, 87.6, 1, 'A/expander'); %A律解壓
%             err(i2)=sum(abs(in-out21));
%         end
%         clear snr in out1 out_ code out21;
%         in=y;
%         figure
%         plot(snr_dB,err);
%         xlabel('信噪比（dB）')
%         ylabel('量化誤差和')
%         title('分析信噪比對量化誤差的影響')
%     end
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    out1=compand(in, 87.6, 1, 'A/compressor'); %A律壓縮
    [out_,code]=u_pcm(out1, Note(i1));  %線性編碼
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    %u_pcm 一個序列的均勻PCM編碼
    %[a_quan,code]=u_pcm(a,n)
    %a=輸入序列
    %n=量化級數(shù)的數(shù)目（偶數(shù)）
    %a_quan=編碼前的量化輸出
    %code=編碼后的輸出
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    out2(i1,:)=compand(out_, 87.6, 1, 'A/expander'); %A律解壓
end
figure
plot(t,out2(1,:),'-o',t,out2(2,:),'-d',t,out2(3,:),'-*',t,in,'r')
legend('量化級數(shù)32','量化級數(shù)64','量化級數(shù)128','原始信號')
xlabel('時間')
ylabel('幅度')
title('量化級數(shù)對信號恢復的影響分析');
figure
plot([1:N], in-out2(3,:),'-r+');  %量化誤差,out_為編碼前的量化輸出
title('量化誤差');xlabel('n');ylabel('dV');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
h0 = figure('Units','points', ...
	'Color',[0.8 0.8 0.8], ...
	'Colormap','default', ...
	'FileName','start.m', ...
	'MenuBar','none', ...
	'Name','量化輸出碼組 ', ...
	'NumberTitle','off', ...
	'PaperPosition',[18 180 476 432], ...
	'PaperUnits','points', ...
	'Position',[230 150 275.25 250.5], ...
	'Resize','on', ...
	'Tag','UIFigure', ...
	'ToolBar','none');
h1 = uicontrol('Parent',h0, ...
	'Units','points', ...
	'BackgroundColor',[1 1 1], ...
	'HorizontalAlignment','left', ...
	'ListboxTop',1.0, ...
	'Position',[10.75 17.5 193.75 223.75], ...
	'String','', ...
	'Style','listbox', ...
	'Tag','NumofSim');
h1 = uicontrol('Parent',h0, ...
	'Units','points', ...
	'BackgroundColor',[1 1 1], ...
	'HorizontalAlignment','left', ...
	'ListboxTop',1.0, ...
	'Position',[210.75 17.5 93.75 23.75], ...
	'String','', ...
	'Style','Text', ...
	'Tag','Rank');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
set(findobj('Tag','NumofSim'),'string',num2str(code))
set(findobj('Tag','Rank'),'string','量化級數(shù)為128')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%