Hi all, I’m trying to understand the approach you use in the 1 M channel tutorial situated in the old tutorial link ( https://casper.berkeley.edu/wiki/Old_Tutorials) called high resolution spectrometer.
I've take a look at other similar implementations like ''A 6*320-MHz 1024-Channel FFT Cross-Spectrum Analyzer for Radio Astronomy'' ( http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1458140), where they use the corner turner technique. Basically they implement the Cooley-Tukey FFT algorithm to have a large DFT coming from two smaller DFT. They use a first stage of corner turner previous to the first DFT and acumulate time samples column wise, to then enter to the First DFT row wise. There is another corner turner stage at the output of the First DFT and after twiddle factor multiplications the data is input again to another DFT. I understand the mathematics behind the above text, but seems to me that the approach used on your 1 MChannel Spectrometer is a little different from that treatment. I can't find the twiddle factors in your model and also you use just one corner turner stage instead of two. So i'm not able to understand how your tutorial works in a mathematical or theoretical sense. Could you give me an advice? where can i find a document to have more details? Thanks in advance. -- *Edgardo Huaracán Durán* *Observatorio Astronómico Nacional* *Universidad de Chile*
