fft - Documentation Question - What is "L"?

Referring to this documentation http://www.mathworks.com/help/matlab/ref/fft.html

What is L?

L = 1000;                     % Length of signal

Is that how many data points you collected? Is that the time interval data points were collected over? Where does the 1000 come from?

Thanks!

Answer 1

[David Young]

It's the number of data points in the synthesised signal vector. It didn't come from anywhere - the person writing the documentation set it because she or he had to decide on some length for the signal.

[Andrew Reibold]

Ok, so if you had a sampling frequency of 1000pts/s, and you took data for 3 seconds, L = 1000 * 3 = 3000?

[David Young]

Yes, exactly.