archive: Re: SETI Some Questions

Re: SETI Some Questions

David Woolley ( david@djwhome.demon.co.uk )
Wed, 2 Sep 1998 23:50:30 +0100 (BST)

[Re wrapped]
> As far as digital signal processing is concerned, is everybody
> still doing the DSP part at audio frequencies? What is the state
> of the art concerning DSP chips these days? Can we expect to be
> doing DSP at the IF some day soon? With 400MHz PC's generally

It is being done at the IF; it just happens that the final IF is around
1.5kHz (assuming SSB filters). There is nothing intrinsically audio
in the signals, so the distinction between IF and audio is arbitrary
and based on the original intended use of the receiver. If you
custom designed the receiver, you could do the A/D conversion at any
centre frequency you chose.

> available, I've got to believe there are some super fast but
> probably (still) expensive DSP chips available.