i am adding gaussian noise signal to an audio signal. but in plotting i am receiving an error " ??? Error using ==> plot Vectors must be the same lengths" how can i make equal vectors?

[y,fs,nbits]=wavread('C:\Users\HP\Desktop\s1.wav');

n=randn(size(y))*sigma+mu*ones(size(y));

ny=length(y);

    nn=length(n);

    N=min([ny nn]);

    Y=y(1:N);

    Z=n(1:N);

signal=Y+Z;
%%%%%%%%%
t = 0:1/fs:1-1/fs;

y = cos(2*pi*1000*t)+1/2*sin(2*pi*2000*t)+randn(size(t));

DF = fs/length(y);

ydft = fftshift(fft(y))

N = length(y);

f=(-1/2:1/N:1/2-1/N)*fs; %%%%%%%%%%%

t = 0:1/fs:1-1/fs;

y = cos(2*pi*1000*t)+1/2*sin(2*pi*2000*t)+randn(size(t));

DF = fs/length(signal);

signaldft = fftshift(fft(signal));

plot(f,abs(signaldft))

[Walter Roberson]

That would be fairly difficult considering that you have not defined "f".

Answer 1

[Walter Roberson]

When you use y(1:N) then you are going to have difficulty if y has multiple channels (e.g., 2 channels for stereo) y(1:N,:) would extract the first N in each channel; y(1:N,1) for the first channel.

At the command line, please command

dbstop if error

and run your program. When it stops, please show

N, size(y), size(signal), size(signaldft), size(f)

Side note: another way of expressing

f=(-1/2:1/N:1/2-1/N)*fs;

would be

f = linspace(-fs/2, fs/2, N+1);
f(end) = [];