An error at modulation process

[sound,fs]=wavread('sesdeneme.wav'); 

fn1 = [10/(7000), 700/(7000)];

[b1,a1] = butter(10, fn1, 'bandpass');

y1=filter(b1, a1, sound);

envelope1 = abs(hilbert(y1));

t=0:0.001:1;

car1=5*cos(2.*pi.*350.*t);

mod1=envelope1.*car1;

plot(t,mod1);grid on

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

i am trying to product envelope1 and car1 but i get this error:

??? Error using ==> times
Matrix dimensions must agree.

Error in ==> implantsonhali at 60
mod1=envelope1.*car1;

Can anyone please help me? :) ty

Answer 1

[Wayne King]

You must not be executing this line

sound = sound(:,1);

sound must be 118784x1, NOT 118784x2

clear everything in your workspace

   >>clear all

Then

    [sound,fs]=wavread('sesdeneme.wav'); 
    sound = sound(:,1);
    fn1 = [10/(7000), 700/(7000)];
    [b1,a1] = butter(10, fn1, 'bandpass');
    y1=filter(b1, a1, sound);
    envelope1 = abs(hilbert(y1));
    t=0:1/fs:(length(y1)*1/fs)-1/fs;
    car1=(5*cos(2.*pi.*350.*t))';
    mod1=envelope1.*car1;
    fn2 = [700/(7000), 1500/(7000)];
    [b2,a2] = butter(10, fn2, 'bandpass');
    y2=filter(b2, a2, sound);
    envelope2 = abs(hilbert(y2));
    mod2=envelope2.*car1;
    plot(t,mod1);grid on,figure;plot(t,mod2);grid on

Just copy and paste what I have given you. After you clear everything.

Answer 2

[Wayne King]

You have a two-channel recording, do this:

 [sound,fs]=wavread('sesdeneme.wav'); 
 sound = sound(:,1);
 fn1 = [10/(7000), 700/(7000)];
 [b1,a1] = butter(10, fn1, 'bandpass');
 y1=filter(b1, a1, sound);
 envelope1 = abs(hilbert(y1));
 t=0:1/fs:(length(y1)*1/fs)-1/fs;
 car1=(5*cos(2.*pi.*350.*t))';
 mod1=envelope1.*car1;
 plot(t,mod1);grid on

Answer 3

[Honglei Chen]

It seems taht your evelope1 is derived from the input sound, while your car1 has the dimension of t, so the two don't match in size.

Answer 4

[emre]

thank you,but how can i solve this problem,any ideas?

Answer 5

[Wayne King]

 [sound,fs]=wavread('sesdeneme.wav'); 
 fn1 = [10/(7000), 700/(7000)];
 [b1,a1] = butter(10, fn1, 'bandpass');
 y1=filter(b1, a1, sound);
 envelope1 = abs(hilbert(y1));
 t=0:1/fs:(length(y1)*1/fs)-1/fs;
 if iscolumn(envelope1)
   t = t(:);
 end
 car1=5*cos(2.*pi.*350.*t);
 mod1=envelope1.*car1;
 plot(t,mod1);grid on

Answer 6

[emre]

thx Wayne but now i get this error:

??? Undefined function or method 'iscolumn' for input arguments of type 'double'.

Answer 7

[Wayne King]

You must not have a version with iscolumn(). That's fine, you don't need that, I just put that in in case the output of filter() is a column vector.

Just make sure that car1 and envelope1 are both row or column vectors

Enter

 >>whos envelope1

if it is column vector, then use

t = t(:);

and you'll be fine.

Answer 8

[emre]

sorry again,when i type it i get this:

Name Size Bytes Class Attributes

envelope1 118784x2 1900544 double

i couldnt understand if it is column or row vector so i tried writing t=t(:); but i get same matrix dimension error.

Tried not to write anything,but still get the dimension error :(

Answer 9

[emre]

thank you Wayne,this is really working but,ş have a last question

when i try to do this more than once,i get the dimension error again.i mean:

[sound,fs]=wavread('sesdeneme.wav'); 
 sound = sound(:,1);

   fn1 = [10/(7000), 700/(7000)];
   [b1,a1] = butter(10, fn1, 'bandpass');
   y1=filter(b1, a1, sound);
   envelope1 = abs(hilbert(y1));
   t=0:1/fs:(length(y1)*1/fs)-1/fs;
   car1=(5*cos(2.*pi.*350.*t))';
   mod1=envelope1.*car1;

fn2 = [700/(7000), 1500/(7000)];
 [b2,a2] = butter(10, fn2, 'bandpass');
 y2=filter(b2, a2, sound);
 envelope2 = abs(hilbert(y2));
 t=0:1/fs:(length(y2)*1/fs)-1/fs;
 car2=(5*cos(2.*pi.*350.*t))';
 mod2=envelope2.*car2;

   plot(t,mod1);grid on,figure;plot(t,mod2);grid on

same error agian when i do this :(

[Wayne King]

tell me what

>>whos y1

>>whos y2

>>whos car1

gives

Answer 10

[emre]

Name Size Bytes Class Attributes

y1 118784x2 1900544 double

Name Size Bytes Class Attributes

y2 118784x2 1900544 double

Name Size Bytes Class Attributes

car1 118784x1 950272 double

I can give my original code if you want.i am writing there summary of it but maybe i am missing smt.

Answer 11

[emre]

thx for all :)