FFT with variable N

[Haggis2013]

I've recently purchased a NI DAQ (NI USB-6356) and would like some help with Labview code please?

I'm collecting about 50,000 sample from my A/D, which I'd like to store in memory or into a file. I'm displaying a power spectrum to find signals at certain frequencies.

Once the signal is present I'd like to do some analysis on the data, namely a sliding FTT on N points at the time. After doing a N-point FFT on the first 256 samples, I'd like to slide along 64 sample and do another 256 point FFT, and so on.

Can you please advice which is the most suitable VI for storing the data? Also is there a VI that allows me do a N-point FFT (where I can set N to any multiple of 2)?

If you can please point me in the right direction on how to proceed I'd be grateful, as I'm fairly new to Labview, although I have plenty of hardware experience.

Thanks a lot!

[Yamaeda]

The FFT.vi has a size-input, just set it to 256. Since you enter an array to the function, and if FFT's the first 256 points, you can simply use array subset with offset to slide the fft window.

/Y