[time-nuts] An (unknown?) nasty feature of the DDS principle for time nuts applications

Ulrich Bangert df6jb at ulrich-bangert.de
Tue Jan 25 14:35:06 UTC 2011


Gerhard,

see page 8.6ff of the service manual to see that the HP3325 is not DDS based
but uses a "Fractional N Synthesizer scheme" which is something completely
different and is not prone to the described effects. Nevertheless it is true
that the HP3325 contibutes phase noise to the measurement but I had
anticipated that this was clear to everybode in the auditorium.

73s de Ulrich, DF&JB

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von dk4xp at arcor.de
> Gesendet: Dienstag, 25. Januar 2011 15:14
> An: time-nuts at febo.com
> Betreff: Re: [time-nuts] An (unknown?) nasty feature of the 
> DDS principle for time nuts applications
> 
> 
>  
> Don't forget that your HP3325 is DDS-based, too, so it adds 
> its own phase error sawtooth.
> 
> 73, Gerhard dk4xp
> 
> 
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