[time-nuts] Secondary phase noise standard & FE405
tshoppa at gmail.com
Sun Nov 13 11:03:31 EST 2016
Some AD DDS app notes give examples of spurs and choosing nearby (but not
exactly on freq) numbers that are much less bad for spurs - or at least
that move the spurs outside the cleanup filters/loops. I don't know of a
general example or even code that does this in a general way.
One paper I like on the subject is this:
P.S. I just like saying "Wheatley Jitter Injector". Not for those who are
embarrassed easily... Almost as good as "Wankel Rotary Engine".
On Sat, Nov 12, 2016 at 8:13 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
> kb8tq at n1k.org said:
> > Yes, the FE-405 uses a DDS and a cleanup. Inside the cleanup loop the DDS
> > spurs come straight through. Since the FE-405 compensates for all sorts
> > things, the DDS moves around a lot. Even a one bit change on a DDS will
> > spurs around. With an ever changing DDS, you have an ever changing
> > of “stuff” on the output.
> Is there a web page or such telling me where the spurs will be on a DDS
> for a
> particular constant?
> These are my opinions. I hate spam.
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