Filtering noisy data

Hello

I have a mixed frequency signal with a lot of noise. I plotted the spectrum of the signal using fft and also plotted the psd of the signal using the sp tool. I don't quite see the peak of the signal in fft plot althought the psd plot shows a peak and then rolls off. I don't know if i am missing to interpret something in the fft plot? I can attach the plots but don't know how. Thanks.

[bym]

what problem are you having with matlab?

[vsee]

I am not exactly having a problem with matlab but just want to attach the plots here so someboy can give a feedback about that. Do you know how do I attach the plot? Thanks

[vsee]

Here is the link to the plot.

http://www.yorkphoto.com/york/slideshow/AlbumID=3615814002/PictureID=206725940002/a=100160453_100160453/

Thanks

Answer 1

[Walter Roberson]

What was plotted for the fft? Real, Imaginary, Magnitude ?

[vsee]

It was the magnitude(log). Here is my code.

hresignal = csvread('2RH8June.csv');

time = hresignal(:, 1);

amp = hresignal(:, 2);

samp = hresignal(1:1000000, 2);

fsamp = 20*log10(abs(fft(samp)));

ps = psd(spectrum.welch,samp);

subplot(2,1,1),plot(fsamp);

subplot(2,1,2),plot(ps);