[hpsdr] High Performance DDS Oscillator source?

[Tayloe Dan-P26412]

I have seen your measurements before and found the results disturbing
(depressing?).  I can only hope the results that you have seen have
improved as the DDS chips themselves have improved.  It would be
interesting to see how the SDR-5000 performs in comparison.

- Dan, N7VE

-----Original Message-----
From: John Ackermann N8UR [mailto:jra at febo.com] 
Sent: Monday, August 13, 2007 1:53 PM
To: Tayloe Dan-P26412
Cc: hpsdr at lists.hpsdr.org
Subject: Re: [hpsdr] High Performance DDS Oscillator source?

Tayloe Dan-P26412 wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> 
> 
> ----------------------------------------------------------------------
> --
> 
> I have an idea that I want to try out that requires a DDS with a very 
> low phase noise.  I was looking at AD9954, which performs best with a 
> 1x frequency source.  I am sure that I have seen this come up before, 
> but did not pay much attention to it.
>  
> Does anyone have a recommendation for a very low phase noise 
> oscillator for this chip and a place that I can get it from?

Dan, this might not be right on point, but I did some phase noise
measurements of an SDR-1000 when driven with different reference sources
including the standard 200 MHz oscillator.  Results weren't quite what
might be expected in that relatively low noise 10 MHz oscillators didn't
perform much worse than the 200 MHz source, despite the multiplication,
and at close offsets could be much better.  Don't know whether that
holds with other DDS parts, though.

Anyway, here's a link to the results: 
http://www.febo.com/pages/hf_phase_noise/index.html

73,
John

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