Re: [Discuss-gnuradio] Welcome and brief update

[Daniel Rogers]

Mark Smith wrote:

> Oy.  40MSps?  Is that a bit overkill for a starting point?  Since the
> chip is easy to interact with (I'm taking your word for it; I've not
> looked at the spec sheet), maybe we should go ahead with that chip, but
> not expect to push a full 480Mbps for the first rev, if it'll make
> things easier.
>
> I agree that it would be nice to be able to finally get to that, but if
> it means getting something out quicker and cheaper, I'd be all for limiting
> to only (say) 400kHz sample rate for FM broadcast, or 12MHz for NTSC.
actually, it seems that I choose 40Msps from a lack of understanding of 
the amount of samples/Hz of radio frequency needed for correct digitization.

That said, how is it that a 400 kHz sample rate is sufficient for a 
107.5 MHz FM modulated signal?  How is it that you can extract useful 
information when you have much muhc less that one sample per cycle.

And given all this information, what is the max frequency you could 
demodulate at 40Msps?

--
Dan

P.S.  It occurs to me that lessons in how radio works not be the 
intention of this list.  If so, I think it may be benificial to all us 
software/non-radio people out there to have something like this.