Tool/software:
Hello,
I'm writing you regarding a question about the FFT that is implemented on the function MmwDemo_computeVitalSignProcessing() of the vitalsign.c code (vital signs open source lab). My concern is about the input, which must have the same dimension as the function input vsDataAngleFftOutBuf, which is 128 samples from 128 frames. More exactly 128x5x9, but the last two dimensions are the range and angle bins, and as the FFT is applied on each one of them, I won't consider those two dimensions.
Before the FFT, you make arc tangent demodulation, phase unwrapping and phase differences of that variable, and store them into pVitalSignsBreathCircularBuffer, which is the actual input of the FFT. However, you seem to only populate the first 128 elements of that array, while the rest are kept as zero. First, I would like to know if I'm understanding the code correctly. Second, I would like to ask you what the advantage of padding the input of the FFT with zeros is. Simply increasing the resolution of the spectrum? And finally, I would also ask if wouldn't be better to use data from more frames (say 256 instead of 128).
Regards.
