[time-nuts] DDS'ery narrow scoped.

Luis Cupido cupido at mail.ua.pt
Tue Jun 21 10:43:53 UTC 2011


Hi Ulrich,

Loop bandwidth could be in the KHz region
or even less.
I could choose more or less freely from Hz to many KHz
but there are obvious tradeoffs and it is hard to decide.
The phase noise of the VCO when I go too narrow versus
the ammount of spurs when I go too wide.
Application is the first LO for an experiment in SDR radio
at VHF-SHF region,(not HF).

Luis Cupido.
ct1dmk.



On 6/21/2011 10:03 AM, Ulrich Bangert wrote:
> Luis,
>
> the information that you are concerned about close carrier spurs that will
> pass through the PLL's low pass filter is not precise enough: are you
> talking about a few Hz, a few ten Hz, a few 100 Hz away from the carrier or
> are you going to build a device for precise timing applications where also
> spurs far below (perhaps orders of magnitude below) 1 Hz may be of concern?
>
> Best regards
> Ulrich Bangert, DF6JB
>
>> -----Ursprungliche Nachricht-----




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