A selection of a time window in order to calculate the fft of my filtered signal

Hello, I am looking to make a selection of a time window in order to calculate the fft of my filtered signal from sample 825 to 932, do you have an idea of the code to do? I admit to being a little lost...

After I have to do a truncation of the filtered signal on this time window I established this code

B= fir1(2,fc/(Fech/2),'low')

But this code is not related to the time window (terminals)..

Thanks for help me

Answer 1

[William Rose]

@Justine Jehlen,

Y=fft(y(825:932));

returns the fft of signal y, from sample 825 through 932.

That seems too easy, so perhaps I have misunderstood your question.