Matrix dimensions must agree spread spectrum code

While trying to create a Spread Spectrum program I had a problem

Matrix dimensions must agree.

Error in untitled5 (line 36)

bpsk_sig=spreaded_sig.*carrier;

I tried to fix this problem, but I couldn't

Code

filename = 'mina.m4a.wma';
fid = fopen(filename, 'r+');
Sound_in_bits = fread(fid, [1 inf]);
fclose(fid);


% Generating the pseudo random bit pattern for spreading
d=round(rand(1,length(Sound_in_bits)));   % "round" is used to approximate the values to 1 and -1 
pn_seq=[];
carrier=[];
 t=[0:2*pi/4:2*pi];     % Creating 5 samples for one cosine 
for k=1:length(Sound_in_bits)
    if d(1,k)==0
        sig=-ones(1,1);
    else
        sig=ones(1,1);
    end
    c=cos(t);   
    carrier=[carrier c];
    pn_seq=[pn_seq sig];
   
end
subplot(3,1,1);  plot(pn_seq); grid;
title('Spreading code');


% Spreading of sequence                                                                
spreaded_sig= Sound_in_bits .* pn_seq;
subplot(3,1,2);  plot(spreaded_sig); grid;
title('Spreaded signal');

% BPSK Modulation of the spreaded signal
bpsk_sig=spreaded_sig.*carrier; 
% Modulating the signal
subplot(3,1,3); 
plot(bpsk_sig);
axis([-1 620 -1.5 1.5]);
title('BPSK Modulated Signal');

Answer 1

[KSSV]

The error is simple...you need to check the dimensions of your variables spreaded_sig and carrier. To use element by element multiplication (.*) they should be of same size if not you will get the mentioned error.

A = rand(5) ;
B = rand(5) ;
C = A.*B ;  % no error 

A = rand(3) ;
B = rand(2) ;
C = A.*B ;   % Error

Matrix dimensions must agree.

[haitham abodoh]

I understand this error, but it means that it wants to solve this error, and we do not know. thanks for your reply .

[KSSV]

Get them to the same size to solve the error.