[time-nuts] Sub Pico Second Phase logger

[Tom]

On Friday 19 December 2008 02:46, Joe Gwinn wrote:
> >  >> 10Hz resolution whilst avoiding phase truncation spurs is
> >  >> impractical
> >>>  with a DDS chip by itself.
> >>>  Depending on the DDS and its clock frequency, the frequency
> >>> spacing of phase truncation spur free outputs may be as large
> >>> as several kHz.
> >>
> >>  Is this true of concatenated DDS chips?  I recall a patent to
> >> the
> >  > contrary.
> >
> >Which patent?
>
> Hmm.  It's at work.  I'll look it up in January.  As I recall, the
> second DDS made a small integer conversion, and so had low spurs,
> while the first DDS was set to whatever was needed.
>
I think you are referring to patent 5598440 about a DDS driven DDS.

Tom