I am simulating a DPCM transmitter and receiver with a 5th order predictor and a 4-bit mid-riser quantizer using a recorded sound file, and the code is as follow:

clc;

clear all;

close all;

y=audioread('MySpeech.wav'); %audioread used to read our speech signal

sound(y); %plays the recorded sound

subplot(3,1,1),

plot(y);

title('recorded voice signal');

grid;

n=length(y);

rxx=xcorr(y); %auto-correlation vector of y

o=5; % order of the predictor

rx=rxx(n+1:n+o); %autocorrelation for the audio signal

R=rxx(n:n+o-1); %autocorrelation vector

Rxx=toeplitz®; %symmetric Toeplitz matrix for real R. Hermitian matrix.

alpha=-inv(Rxx)*rx; %predictor parameter

Vpp=max(y);

delta=2*Vpp/16; %to calculate stepsize

x_t=zeros(1,o); %1*P matrix of zeros

c=zeros(1,n+o);

x_c=zeros(1,n+o);

%transmitter of DPCM

for p=o+1:n+o

for j=16:o % to calculate output of predictor

x_c(p)=x_c(p)-x_t(p-j)*alpha(j);

end;

d(p)=y(p-o)-x_c(p); %to calculate differential input

fori=1:(16/2) % loop to calculate output of quantizer

if((i-1)*delta<=d(p) && d(p)<(i)*delta &&i<(16/2))

d_c(p)=(i-0.5)*delta;

elseif (d(p)>=(i-1)*delta)

d_c(p)=(i-0.5)*delta;

elseif (d(p)< -(i-1)*delta)

d_c(p)= -(i-0.5)*delta;

elseif (-(i+1)*delta<=d(p) && d(p)<-(i)*delta &&i<(l/2))

d_c(p)=-(i-0.5)*delta;

end;

end;

x_t(p)=d_c(p)+x_c(p); %to calculate input of predictor

if(d_c(p)>=0) % to calculate output of encoder

c(p)=((d_c(p)/delta)-0.5);

else

c(p)=(abs((-d_c(p)/delta))-0.5)+(16/2);

end;

subplot(3,1,2)

plot(d);

sound(d)

title('transmitted signal');

grid;

cTx=dec2bin(c,4); %decimal to binary conversion

%receiver of DPCM

cRx=bin2dec(cTx); %binary to decimal conversion

ydr=zeros(1,o); %1*P matrix of zeros

y_cr=zeros(1,n+o);

for p=o+1:n+o

for j=1:o

y_cr(p)=y_cr(p)-ydr(p-j)*alpha(j);%to calculate output of prediction

end;

fori=0:16-1 % to calculate output of decoder

if (cRx(p)==i)

j=i;

if (cRx(p)<(16/2))

d_cr(p)=(j+0.5)*delta;

elseif (cRx(p)>=(16/2))

d_cr(p)=-((j-(16/2))+0.5)*delta;

end;

break;

end;

end;

ydr(p)=d_cr(p)+y_cr(p); %to calculate input of predictor

subplot(3,1,3)

plot(ydr);

title('reconstructed voice signal');

grid;

sound(ydr);

#################

and i am getting this message:

would anyone please help me solving this problem pleeeeease

[Chi Shing Poon]

Did you ever find a solution?