On 10/14/09 12:25 PM, "Luis Cupido" <cup...@mail.ua.pt> wrote:
> Hi,
>
> I'm looking for the schemes used on the
> frequency synthesizers that change frequency
> in few microseconds time (or less)
> at microwaves lets say circa 12-18Ghz)
> Obviously with some resolution (let's say 100Khz step
> or in that order)(otherwise it would
> be a trivial exercise in the BW of the PLL loop filter)
>
> Does anyone know of some paper or tech notes from
> some instrument or modules that show block diagrams
> of such?
Look at how the PTS synthesizers work.. A series of decade modules, lots of
adding, mixing, filtering. Off the shelf they do sub microseconds.
A DDS feeding a multiplier (not a PLL mult, but a step recovery diode or
similar) also will have very fast switch time, and might even be phase
continuous. Your challenge with this approach is going to be spurs.
>
> I have many info on mw synthesizers but all fall into
> microwave radio style of things with much higher
> resolution (khz and less) and much longer
> switching times (millisencods or more).
> Info on fast stuff I can't really find.
That's partly because fast frequency hoppers and frequency agile radars are
export controlled, and that's one of the applications of a fast switching
synthesizer.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
