RE: [linrad] Mixer design - comments please

[Edson Pereira <edson@xxxxxxxxxxxxxxxxx]

Hi Bob,

I understand the need for square levels for the multiplexer. For some
reason I thought that the AD9852 already had a digital I/Q output. I
reread the datasheet and found that the chip only provides a comparator.

-- Edson

On Tue, 8 Jul 2003, Robert McGwier wrote:

> The IQ outputs are sine and cosine.  You need
> square wave.
> 
> Bob
> N4HY
> 
> 
> -----Original Message-----
> From: owner-linrad@xxxxxxxxxxxxxxxxxxxxxx
> [mailto:owner-linrad@xxxxxxxxxxxxxxxxxxxxxx]On Behalf Of Edson Pereira
> Sent: Tuesday, July 08, 2003 04:41
> To: linrad@xxxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [linrad] Mixer design - comments please
> 
> 
> 
> Hi Alex,
> 
> Since the input range of some soundcards can be in the range of 10 vpp, it 
> may be better to use a 10V supply for the Op-Amps. You may also consider 
> using the NE5532 instead of the NE5534 to lower the component costs.
> 
> What type of LO source are you planning in building? 
> 
> Looking at the DDS schematics presented in the SDR-1000 article, I don't
> understand why Gerald used lowpass filters and than a comparator if the
> DDS already has a square I/Q output.
> 
> 73,
> 
> -- Edson, 7n4ncl
> 
> 
> 
> 



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