matlab-基于matlab的PCM编码解码性能仿真-源码

function [BIN_Quantized, mx, bitslevels]= Quantizer(signal) prompt = 'Enter 0 for midrise unifrom quantizer, and 1 for non uniform quantizer '; x = 0; prompt_1 = 'Quantizer no of bits? '; bitslevels = 10; figure(2) subplot(2,1,1) stem(signal); title('Sampled Signal', 'LineWidth', 7); xlabel('samples'); ylabel('signal'); switch x case 0 levels=[]; nolevels= 2^bitslevels; m_max=max(abs(signal)); delta=(2*m_max)/nolevels ; k_max=nolevels/2; pos_levels=[]; i=1; for k=0:2:2*(k_max-1) pos_levels(i)=(1+k)*(0.5*delta); i=i+1; end neg_levels=[]; j=1; for kk=0:2:2*(k_max-1) neg_levels(j)= -(1+kk)*(0.5*delta); j=j+1; end levels=[fliplr(neg_levels) pos_levels]; Quantized=[]; Quantized_plt=[]; for i=1:length(signal) [~ ,I] =min(abs(pos_levels-abs(signal(i)))); if signal(i)>0 Quantized(i)= I+length(neg_levels)-1; Quantized_plt(i)= pos_levels(I); else Quantized(i)= length(neg_levels)-(I-1)-1; Quantized_plt(i)= neg_levels(I); end end % t1=linspace(0,2, length(Quantized_plt)); subplot(2,1,2) stem(Quantized_plt); title('Quantized Signal', 'LineWidth', 7); xlabel('samples'); ylabel('signal'); case 1 prompt = 'Enter the value of mu '; mu = input(prompt); % signal= [3,9,-28,10,-34,-22,-4,24,18,30,-16]; %Performing mu-law compression of the input signal signal_comp= sign(signal).*log(1+mu*abs(signal))/log(1+mu); % uniform Quantization using n-bit quantizer Quantized_sign=Quantizeer(signal_comp,bitslevels); %Expanding the output of the mu law quantizer Quantized= sign(Quantized_sign)*(1/mu).*((1+mu).^(abs(Quantized_sign))-1); %plotting the Quantized signal stem(Quantized); end mx= m_max; BIN_Quantized= reshape((fliplr(de2bi(Quantized, bitslevels)))', 1,[]); end