By increasing the length of the FFT you lower the apparent noise floor in the FFT magnitude plot and are able to detect smaller signals. That's called "FFT processing gain". The formula is:
FFT gain = 10*log(M/2)
where M is the number of points processed in the FFT. Doubling the number of points, lowers the apparent noise floor by 3 dB.
(I don't know if that's what the researchers actually did. I'm just explaining what the comment presumably meant.)
FFT gain = 10*log(M/2)
where M is the number of points processed in the FFT. Doubling the number of points, lowers the apparent noise floor by 3 dB.
(I don't know if that's what the researchers actually did. I'm just explaining what the comment presumably meant.)