[time-nuts] fast switching quiet synthesizer
alan.melia at btinternet.com
Tue Oct 7 13:47:37 EDT 2014
Jim I am not sure if this will meet your requirement for "hygene" but google
Trinity Power Inc (Bob Yarbrough) he has a unit that was featured in EDN
some time around a year ago. I doesnt switch fast enough at present but that
could be altered..... the problem might be that I think it is a PLL Rather
than a DDS..... But might be worth a look ....I know the PTS I have a couple
of earlier Wavetek- Rockland units ...one TTL and one GPIB also an Adret 201
which uses the same technique.
----- Original Message -----
From: "Jim Lux" <jimlux at earthlink.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Tuesday, October 07, 2014 6:02 PM
Subject: [time-nuts] fast switching quiet synthesizer
> At work, I'm putting together a multichannel stepped frequency CW radar
> breadboard, and I'm looking for something to serve as a source that I can
> step quickly.
> I'm looking at stepping every millisecond or so. Right now, I use a
> Ardunino type microcontroller driving a serial DAC driving a VCO, but
> that's a bit wonky and noisy, although it's easy to get the step timing
> right on. The spectral purity is, shall we say, downright ugly.
> Since I'm going to be doing precision ranging with this, the spectral
> purity has to be reasonably good (not 1E-15 at 1000 seconds good,
> I was thinking about a PTS synthesizers (beloved of time-nuts for all
> kinds of reason), and they're nice because they are quiet, and switch
> really fast (microseconds). However, they all seem to have BCD or GPIB
> interfaces (only). Sure, I can code up something on an Arduino or other
> microcontroller to drive the BCD on the PTS, but maybe there's something
> else out there that might work as well? And is already off the shelf.
> I could hook a Prologix on the back of a PTS with GPIB, and hit it over
> the ethernet, but I'm not sure I'd be able to get the steps to occur when
> I want them (ethernet and determinism do not go well together).
> Maybe some DDS in a box product? That will take my nice clean 10 MHz
> Ultimately, I'm looking at output frequencies in single digit GHz, but
> something that can be mixed/multiplied up will work just fine.
> I'm looking for something that is off the shelf-ey as much as possible.
> Using surplus gear is ok, because I really only need 3 or 4 channels and
> that might be scroungeable, but spending hours wiring up weird adapters or
> locating connectors that haven't been made since 1943 is something I'd
> like to avoid.
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