Cross spectral density in a fixed time window and frequency

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Lidia 2014-7-9

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https://ww2.mathworks.cn/matlabcentral/answers/141037-cross-spectral-density-in-a-fixed-time-window-and-frequency

Hi all,

I have two time series x and y, both [1 x 1801 x 53] type double, so each has 53 trials of 1801 time (sample) points. I would like to compute cross spectral density at time window set from 1201 to 1801 time points and at 5 - 100 Hz frequency band. Also I need to obtain cpsd values at every 0.5 Hz. Can I do it this way?

x = mean(x,3); averaging across trials - if I don't do it, cpsd doesn't work y = mean(y,3);

[Cxy,F]=cpsd(x,y,hamming(600),[],1801,200);

hamming window is a segment of length 600 tp selected from both time series - how can I be sure it selected exactly last 600 time points (1201:1801) of both x and y?

[] -this is meant to be noverlap - is it overlap between time series or maybe betwenn extracted time segments if hamming window selects more then one segment.

sampling frequency fs = 200 so range of frequncies for the cross spectrum should be [0,fs/2] for real signals which would give me the frequency band of 0-100 Hz and that's satisfying but is there a way to compute it in a range [5,100] Hz?

Many thanks for any help!!

Lidia