Thread Subject: moving windows for welch power spectrum

Can any one tell me how to perform welch power spectrum on the EEG data using moving
windows in matlab?

"rams dhiga" wrote in message <j9n5ue$d9s$1@newscl01ah.mathworks.com>...
> Can any one tell me how to perform welch power spectrum on the EEG data using moving
> windows in matlab?

http://www.mathworks.com/matlabcentral/fileexchange/11690-specwelch

"rams dhiga" wrote in message <j9n5ue$d9s$1@newscl01ah.mathworks.com>...
> Can any one tell me how to perform welch power spectrum on the EEG data using moving
> windows in matlab?

In the Signal Processing Toolbox, see

pwelch

or
spectrum.welch

"Wayne King" wrote in message <j9oe6j$8ff$1@newscl01ah.mathworks.com>...
> "rams dhiga" wrote in message <j9n5ue$d9s$1@newscl01ah.mathworks.com>...
> > Can any one tell me how to perform welch power spectrum on the EEG data using moving
> > windows in matlab?
>
> In the Signal Processing Toolbox, see
>
> pwelch
>
> or
> spectrum.welch

But I need to implement this with moving windows.Can you tell me how?

On Nov 14, 8:47 am, "rams dhiga" <ramya_kool...@yahoo.com> wrote:
> "Wayne King" wrote in message <j9oe6j$8f...@newscl01ah.mathworks.com>...
> > "rams dhiga" wrote in message <j9n5ue$d9...@newscl01ah.mathworks.com>...
> > > Can any one tell me how to perform welch power spectrum on the EEG data using moving
> > > windows in matlab?
>
> > In the Signal Processing Toolbox, see
>
> > pwelch
>
> > or
> > spectrum.welch
>
> But I need to implement this with moving windows.Can you tell me how?

But that's what Welch is.
The power spectrum of a moving window that you define using the
parameters window and noverlap.
Did you read the documentation for pwelch?

TideMan <mulgor@gmail.com> wrote in message <d8d3aa1f-619b-4176-9dad-ecd7cf43ef48@y7g2000vbe.googlegroups.com>...
> On Nov 14, 8:47 am, "rams dhiga" <ramya_kool...@yahoo.com> wrote:
> > "Wayne King" wrote in message <j9oe6j$8f...@newscl01ah.mathworks.com>...
> > > "rams dhiga" wrote in message <j9n5ue$d9...@newscl01ah.mathworks.com>...
> > > > Can any one tell me how to perform welch power spectrum on the EEG data using moving
> > > > windows in matlab?
> >
> > > In the Signal Processing Toolbox, see
> >
> > > pwelch
> >
> > > or
> > > spectrum.welch
> >
> > But I need to implement this with moving windows.Can you tell me how?
>
> But that's what Welch is.
> The power spectrum of a moving window that you define using the
> parameters window and noverlap.
> Did you read the documentation for pwelch?

Yes,pwelch is itself has moving window concept.Could you also tell me how to implement moving windows for the fft/dft of the eeg data I have?

"rams dhiga" wrote in message <j9p6rs$iau$1@newscl01ah.mathworks.com>...
> "Wayne King" wrote in message <j9oe6j$8ff$1@newscl01ah.mathworks.com>...
> > "rams dhiga" wrote in message <j9n5ue$d9s$1@newscl01ah.mathworks.com>...
> > > Can any one tell me how to perform welch power spectrum on the EEG data using moving
> > > windows in matlab?
> >
> > In the Signal Processing Toolbox, see
> >
> > pwelch
> >
> > or
> > spectrum.welch
>
> But I need to implement this with moving windows.Can you tell me how?
this is an example without specifying window


%Define a cosine of 200 Hz, add noise and view its spectral content using the Welch %algorithm.
Fs=1000;
t=0:1/Fs:.3;
x=cos(2*pi*t*200)+randn(size(t));
Hs=spectrum.welch;
psd(Hs,x,'Fs',Fs)
%%%%%%%%%%%%%%%%ù
this is another exemple by specifying length and kind window (hann window ) you can change the kind or the lengh or the noverlapping (noverlap must be < lengh of window)
Fs = 1000;
t = 0:1/Fs:.3;
x=cos(2*pi*t*200)+randn(size(t));
window=33;
noverlap=32;
nfft=4097;
h = spectrum.welch('Hann',window,100*noverlap/window);
hpsd = psd(h,x,'NFFT',nfft,'Fs',Fs);
Pw = hpsd.Data;
Fw = hpsd.Frequencies;
 psd(h,x,'NFFT',nfft,'Fs',Fs)