On Tue, 02 Jun 2020 05:52:13 +
"Poul-Henning Kamp" wrote:
> I have played with this one:
>
> http://www.rudius.net/oz2m/ngnb/dds.htm
>
> as a synthesizer replacement in the HP5065, but your "dual" configuration
> and the integrated 1GHz "pre-oscillator" would fit that purpose better,
From: time-nuts on behalf of Anders Wallin
Sent: Tuesday, June 2, 2020 7:38 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Microstepper
There is now a first draft of the 'DDS-board', a 4-layer 100mm x 100mm PCB
In message
, Anders
Wallin writes:
>I will order a few prototype PCBs in a few weeks. In the meantime if anyone
>has comments/suggests on the schematic or PCB from previous experience with
>ADF4351, AD9912, or similar ICs then please let me know.
I have played with this one:
There is now a first draft of the 'DDS-board', a 4-layer 100mm x 100mm PCB
with an ADF4351 PLL+VCO, and two AD9912 DDSs over here:
https://ohwr.org/project/microstepper/wikis/2020-06-02-DDSboard-draft
(kicad sources in the repository at
https://ohwr.org/project/microstepper/tree/master/ddsboard)
Hoi Anders,
On Tue, 14 Jan 2020 08:58:30 +0200
Anders Wallin wrote:
> The obvious way to increase resolution (make the smallest frequency step
> smaller) is to lower the IF.
> I guess the limit is that we don't want the IF to feed-thru the
> phase-detector and PLL all the way to a PN-spur in
Hi
The closer the beat note / spur / crud is to carrier, the bigger its effect on
things
like ADEV and other timing issues. Indeed 97 KHz is pretty far out compared to
most of what people worry about. It is also quite far compared to the PLL
bandwidth
of just about anything you normally would
Anders
I took an initial look at your work.
No technical comments
The presentation of details is excellent. I had not seen this quality in a
wiki. Normally very simple. Look forward to a more detailed read.
Thank you for sharing.
Regards
Paul
WB8TSL
On Tue, Jan 14, 2020 at 1:59 AM Anders Wallin
prototype block-diagram, short list of chips in the implementation, and a
discussion on resolution now on ohwr.org:
https://ohwr.org/project/microstepper/wikis/Block-diagram
The obvious way to increase resolution (make the smallest frequency step
smaller) is to lower the IF.
I guess the limit is
Hi,
Many thanks for those references. Downloaded and stored for future
reference and reading.
Check out US4358741 and US4417352.
Cheers,
Magnus
On 2020-01-02 18:10, Anders Wallin wrote:
> fwiw, looks like the spectradynamics patent expired today:
>
fwiw, looks like the spectradynamics patent expired today:
https://patents.google.com/patent/US6278330B1/en
afaik that design (more or less) is also described in
https://doi.org/10.1109/FREQ.1998.717932
a variation is also https://doi.org/10.1109/EFTF.2012.6502322 (which might
be sold by
Hi Dana,
On 2019-12-25 17:14, Dana Whitlow wrote:
> Thanks, Bob, for clarifying what Magnus means by "microstepper". To me,
> the term has always referred to operation between the discrete steps defined
> by the polepieces and windings. One can do it (albeit poorly) with many
> stepper
>
Thanks, Bob, for clarifying what Magnus means by "microstepper". To me,
the term has always referred to operation between the discrete steps defined
by the polepieces and windings. One can do it (albeit poorly) with many
stepper
motors. There is a class of servo motor in which the designers of
Dana,
What motor? I have no motor involved here.
Alternating between frequencies causes modulation I try to avoid, a DDS
is a good way to avoid that, but I was hoping to keep phase noise low.
Cheers,
Magnus
On 2019-12-25 03:03, Dana Whitlow wrote:
> Magnus,
>
> Why not just clock a good DDS
Hi
Different sort of micro stepper. The 3D printing version runs a stepping motor
to improve the angular resolution. As you mention, the poles in the motor limit
just how well you can do. There are dedicated chips out there these days that
get down below the limits on any motor I’ve ever seen.
Hi,
That was not exactly what I was aiming for, but you got one aspect
potentially better than I proposed, that the offset generator is running
off the input. That is for sure a variant I did not think about as I
wrote it, but that was in my mind in an earlier variant of thoughts.
Now, the
Magnus,
Why not just clock a good DDS (AD9854) with the reference frequency, and
run its
I & Q outputs into the motor via suitable LP filters and some power gain?
You might
need to periodically alternate between two different output frequencies to
get the desired
rotation speed (as with a
Something like this? (see image)
On Wed, Dec 25, 2019 at 1:02 AM Magnus Danielson wrote:
>
> Hi,
>
> I realize that I lack a microstepper. Consider that I have a stable and
> low-noise 5 or 10 MHz but I want to resynthesize to correct frequency
> and do phase-steps, and doing so without too much
Hi,
I realize that I lack a microstepper. Consider that I have a stable and
low-noise 5 or 10 MHz but I want to resynthesize to correct frequency
and do phase-steps, and doing so without too much loss of noise.
This has traditionally been done using a variation of techniques, but if
we would use
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