[hpsdr] Call for Comments and Discussion - OzyII

[Alberto I2PHD]

jeff millar wrote:
> 
> Linrad uses a series of FFT's to break down a 96 KHz sample stream into 
> SSB or CW bandwidths. The size of the FFTs depends the bandwidth of the 
> incoming sample stream. For a wide band SDR, the size of the FFT will 
> grow and the processing power also grows by what's called "N log(N)".

You don't need a series of FFTs to reduce the bandwidth....
You can just do a downconversion (lowpass filtering + decimation)
on the time domain signal. Using FFTs to do that is not much
computationally efficient.

This is how it is done in Winrad, and it works. In Winrad the FFTs
are used only for the visual aspects of the program (apart from the
final bandpass filtering, done with the overlap-and-save technique).

73  Alberto  I2PHD

 1248466902.0