Re: [Discuss-gnuradio] AR5000 and downconversion

[brian whitaker]

Alan,

I thought that many of the applications for SDR had baseband bandwidths 
on the order of 10MHz... how low of an IF are you looking for?  Check 
out the datasheet for the max2450 (http://www.maxim-ic.com/max2450) -- 
its an I/Q mod/demod, but its set up for a 70MHz IF, so it won't work 
here.

I'm looking into a zero-IF solution, but it seems like a 10.7MHz IF 
solution makes your 20Msps ADC _almost_ good enough -- how much margin 
over Nyquist are you looking for?  It just seems too easy to stick with 
10.7 since LOs, filters, etc are sooooo cheap. I take it you really 
like your ADC?

Brian.

On Wednesday, May 14, 2003, at 06:52 AM, Alan Gray wrote:

> Hi all,
>
> I've recently found that I have access to several standard radio
> receivers,
> including an AOR AR5000 and AR8600. Naturally, these both have a 
> 10.7MHz
>
> output IF and thus aren't much use in combination with my 20MSPS A/D
> card
> but I was wondering if anyone has looked into the possibility of adding
> an
> extra downconversion stage after this to obtain a usable IF.
>
> I haven't much experience in dealing with the radio side of things, but
> a
> quick look at some books on the subject seem to indicate that it might
> not
> be too hard a circuit to put together. If anyone has looked into doing
> this
> or has ideas on if it will/will not work, any information would be most
> welcome
>
> Alan
>
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