[ARC5] [Milsurplus] AD9850 DDS Freq. Syth Module

[Mike Feher]

Hi Mike -

It all depends on the application. DDS spurs can be pretty bothersome,
especially in satellite communications. The biggest contributor is the
number of bits in the D/A converter that follows the accumulator. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 

-----Original Message-----
From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of mstangelo at comcast.net
Sent: Saturday, March 23, 2013 10:35 AM
To: Bruce Long; arc5 at mailman.qth.net
Subject: Re: [ARC5] [Milsurplus] AD9850 DDS Freq. Syth Module

The spurs generated by the AD9850 abd AD9851 are not that objectionable.

If you're concerned about spurs and phase noise I would use a DDS which has
more resolution (more bits) in the D to A converter such as the AD9951.
Check out WA1FFL's kit:

<http://www.wa1ffl.com/>

I believe the concern about DDS spurs is overblown. ICOM uses the AD9951 in
their IC-7000 and IC-7200 for their synthesizer and I haven't heard
complaints about spurs.

<http://www.ab4oj.com/icom/trend.html>

Mike N2MS
----- Original Message -----
From: Bruce Long <coolbrucelong at yahoo.com>
To: George at MaierGroup.com, arc5 at mailman.qth.net
Sent: Fri, 22 Mar 2013 23:44:54 -0000 (UTC)
Subject: Re: [ARC5] [Milsurplus] AD9850 DDS Freq. Syth Module

George. I don&#x27;t know anything about the product you refered to but
years ago as part of my day job I freq locked a ocxo quartz osc to a gps
receiver using that general approach   It worked great with no big problems 

As an ex high performance receiver designer at wj I am uncomfortable with
the spurs generated bu Dds sources although I admit the dds spur level is
too low to worry about in most ham applications.  I like the idea of a good
lc vfo stabilized wIth a non PLL approach bruce
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