Do you mean delay-generators for 1PPS? Or a finely-tunable frequency
synthesizer?

For 1PPS, the fine-delay FMC card might be worth a look:
http://www.ohwr.org/projects/fmc-delay-1ns-8cha/wiki

afaik it works by first time-stamping the input pulse, then delaying the
output with an integer number of clock cycles on the FPGA, and for
sub-cycle fine delay it uses programmable hardware delay-lines (these run
quite hot on the board),
If you need only 1PPS that is synchronous to some input 10MHz signal then
the design is much simpler since you don't need to time-stamp an
asynchronous input pulse first.

SRS DG645 and similar might be worth a look too.

Anders

On Wed, Dec 9, 2015 at 12:26 PM, Attila Kinali attila@kinali.ch wrote:

On 12/9/2015 2:26 AM, Attila Kinali wrote:

My extensive experience with digging up old articles (before the
internet, the library was like my second office) is that when
the trail goes cold on some topic for no apparent
reason, it turns out that there is a (non-apparent) good reason
why no one is writing about the topic any more.  I usually
got to the bottom of this by asking experts in the industry.

My general impression about phase microsteppers based on when I
was involved in the time industry is that they didn't have a
very good reputation and were an inferior solution that was
used as an expediency because it it could be "bolted on"
to an existing system that wasn't originally designed to be
tuned.  I think the concensus was that direct digital synthesis
is the better way to go, assuming you can design it into the
architecture in the first place.  DDS is a pretty well developed
technology at this time that is supported by good OTS chips,
so it is not clear what the value proposition would be for
phase microsteppers.

When we were designing the 5071A 25 years ago, it was clear
that the method of tuning by varying the C field was not
acceptable for a state of the art standard.  There are
multiple reasons for this decision.  At the time,
there were a few DDS chips, but we had to roll our own DDS
due to the stringent and specialized requirements.  It took
a whole PC board for this circuit at the time.  The possibility
of using a phase microstepper was never even considered AFAIK.

Are you aware of some redeeming value that phase microsteppers
have that would make us want to investigate them?  Am I
being too harsh on them?  Maybe you can champion them and they
will make a come back :-)

Rick Karlquist N6RK

it is not a hint, for what you asked, but if you add a DC voltage to the
output of the phase detector in an analog PLL the VCO phase could be
adjusted, similarly if you add a constants to the  input data of a phase
accumulator of the NCO you could adjust the phase of the NCO
but be aware, the NCO will have always more jitter than a VCO
get Giora's book -- see my previous e-mail
also QAM demodulators used phase rotators too...
73
KJ6UHN
Alex
On 12/9/2015 2:26 AM, Attila Kinali wrote:

A phase microstepper is useful with many older Rb and Cs standards (e.g., 5061A and 5065A) so that you don't have to touch the C-field. It is also useful with a 5071A to improve the time sync/step/steer resolution.

Note that you can also implement a GPSDO with a phase microstepper and this allows you to avoid Vref, DAC and EFC. Not all LO have EFC, and even if they do, it may be more stable not to use EFC. Plus with a DDS you avoid EFC-out-of-range problems.

See also http://leapsecond.com/pages/fe405/ and the links near the bottom. This (patented) FEI design avoids the spur issues several of you have been talking about: the RF output comes from a low-noise VCXO not the low-drift OCXO+DDS itself.

And finally, another very interesting use of a DDS as a sort of microstepper phase comparator is:
http://www.ptfinc.com/dsheets/App_35_picoPak.pdf

/tvb

Hi Attila:

Once you find a patent you can then  search on the class number for very similar patents.
See the links under "Handy External Links:"
http://www.prc68.com/I/Learning.shtml
Quick allows searching for a class number or other fields (but not the text of the patent).
PS Sunnyvale has a patent library where they file US patents by class number making manual searches fairly easy.
Top Level Class # http://www.uspto.gov/go/classification/selectbynum.htm (left) allows you to see the meaning of the
class to be sure that's what you're interested in.

US 4358741 https://www.google.com/patents/US4358741 Micro time and phase stepper, 331/2
https://www.google.com/url?id=rl0dBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc331/defs331.htm&usg=AFQjCNHhVSrSreshQPR_PYhdLJ0aw9tBCQ#C331S002000,
327/161
https://www.google.com/url?id=rl0dBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc327/defs327.htm&usg=AFQjCNFoZx7H6EhU2a-QMFPGAY1I73oBzw#C327S161000,
333/18
https://www.google.com/url?id=rl0dBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc333/defs333.htm&usg=AFQjCNF4ObmgvfHFQi9OPkPToOvejSWAZg#C333S018000,
331/25
https://www.google.com/url?id=rl0dBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc331/defs331.htm&usg=AFQjCNHhVSrSreshQPR_PYhdLJ0aw9tBCQ#C331S025000

CLASS 331, OSCILLATORS

2 Plural oscillators controlled: javascript:poptastic('../shadowFiles/defs331sf.htm?331_2&D&2&3');

25 Signal or phase comparator: javascript:poptastic('../shadowFiles/defs331sf.htm?331_25&D&2&J&Q');

CLASS 327,MISCELLANEOUS ACTIVE ELECTRICAL NONLINEAR DEVICES, CIRCUITS, AND SYSTEMS
161 With delay means: javascript:poptastic('../shadowFiles/defs327sf.htm?327_161&D&2S&3X&4H');

286 With counter: javascript:poptastic('../shadowFiles/defs327sf.htm?327_286&D&2S&79&7X&7Y');

US 4417352 https://www.google.com/patents/US4417352?dq=US4417352 Microphase stepper employing improved digital timing
incrementer employing a rate multiplier, 377/43
https://www.google.com/url?id=Jt8eBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc377/defs377.htm&usg=AFQjCNES34nVJJvy1BQF6eXy2lUwpG20wg#C377S043000,
377/47
https://www.google.com/url?id=Jt8eBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc377/defs377.htm&usg=AFQjCNES34nVJJvy1BQF6eXy2lUwpG20wg#C377S047000,
327/286
https://www.google.com/url?id=Jt8eBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc327/defs327.htm&usg=AFQjCNFoZx7H6EhU2a-QMFPGAY1I73oBzw#C327S286000,
377/52
https://www.google.com/url?id=Jt8eBAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc377/defs377.htm&usg=AFQjCNES34nVJJvy1BQF6eXy2lUwpG20wg#C377S052000

CLASS 377,ELECTRICAL PULSE COUNTERS, PULSE DIVIDERS, OR SHIFT REGISTERS: CIRCUITS AND SYSTEMS
43 Having phase shift: javascript:poptastic('../shadowFiles/defs377sf.htm?377_43&D&T&19');

47 Pulse multiplication or division: javascript:poptastic('../shadowFiles/defs377sf.htm?377_47&D&T&1D');

52 With programmable counter (i.e., with variable base):
javascript:poptastic('../shadowFiles/defs377sf.htm?377_52&D&T&1I');

US 5440313 https://www.google.com/patents/US5440313 GPS synchronized frequency/time source (Q5200
http://www.prc68.com/I/Q5200.shtml), 342/352
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc342/defs342.htm&usg=AFQjCNHmJcOXqM2sgcclreqTZjYK9v88aQ#C342S352000,
375/362
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc375/defs375.htm&usg=AFQjCNFcuagMfSu6xvEzMh0uBF37Cw37ZA#C375S362000,
368/200
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc368/defs368.htm&usg=AFQjCNH9PXe6MYSffVhm9JQ8TwfbzXRIrA#C368S200000,
342/357.29
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc342/defs342.htm&usg=AFQjCNHmJcOXqM2sgcclreqTZjYK9v88aQ#C342S357290,
342/357.42
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc342/defs342.htm&usg=AFQjCNHmJcOXqM2sgcclreqTZjYK9v88aQ#C342S357420,
342/357.59
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc342/defs342.htm&usg=AFQjCNHmJcOXqM2sgcclreqTZjYK9v88aQ#C342S357590,
342/357.68
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc342/defs342.htm&usg=AFQjCNHmJcOXqM2sgcclreqTZjYK9v88aQ#C342S357680,
342/357.48
https://www.google.com/url?id=vp08BAABERAJ&q=http://www.uspto.gov/web/patents/classification/uspc342/defs342.htm&usg=AFQjCNHmJcOXqM2sgcclreqTZjYK9v88aQ#C342S357480

CLASS 342,COMMUNICATIONS: DIRECTIVE RADIO WAVE SYSTEMS AND DEVICES (E.G., RADAR, RADIO NAVIGATION)
352 Including a satellite: javascript:poptastic('../shadowFiles/defs342sf.htm?342_352&D&60&62');

CLASS 368,HOROLOGY: TIME MEASURING SYSTEMS OR DEVICES
200 For adjusting the frequency or beat: javascript:poptastic('../shadowFiles/defs368sf.htm?368_200&D&54&5K');

CLASS 375, PULSE OR DIGITAL COMMUNICATIONS

62 Frequency or phase control using synchronizing signal:
javascript:poptastic('../shadowFiles/defs375sf.htm?375_362&D&5F&5N');

I haven't shown all of the class number detail, but there's a lot of class numbers to look at.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html

Attila Kinali wrote:

Hi Tom:

While I was working at TRW Microwave we were purchased by FEI.  It's my understanding the their key capability was in
the crystal material in that it produced the cleanest oscillators on the market.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html

Tom Van Baak wrote:

Attila,

Try these search terms:
phase microstepper
microphase stepper
time frequency phase "offset generator"
auxiliary offset generator
phase frequency AOG
programmable clean-up oscillator

The two commercial products I'm familiar with get down to 1e-19 resolution:

http://www.microsemi.com/products/timing-synchronization-systems/time-frequency-references/active-hydrogen-maser/aog-110

http://www.spectradynamics.com/products/hrog-5-high-resolution-phase-and-frequency-offset-generator

Somewhere I have the block diagram for these. Very complex. Depending on the resolution and stability specs you need a DDS solution might be simpler today.

The write-up about Bert's DDS board is here:
http://leapsecond.com/pages/ad9913/
http://www.analog.com/media/en/technical-documentation/data-sheets/AD9913.pdf

You'll want to use a DDS with a "programmable modulus" feature:
http://www.analog.com/media/en/technical-documentation/application-notes/AN-953.pdf

/tvb

Hi,

Vremya also have such boxes. The current one, VCH-317, goes under the
name "Real-Time Atomic Clock Combiner" which may not give you the
initial association of it being a micro-stepper. I have read the manual
for an older box, or at least an older description, which included a
nice description and overview, but I could not locate it.

"offset generator" is a re-occuring theme common to AOG and HROG.

The SpectraDynamics HROG is in patent US6278330.

As always, it can be interesting to look up cited patents and check what
else that company or inventor may have come up with.

Cheers,
Magnus

On 12/09/2015 10:51 PM, Tom Van Baak wrote:

Hi

It avoids the far removed spurs. If you have a close in spur, it passes right through the PLL loop and messes up your ADEV.
Yes, this really does happen on real gear in the real world …..

Bob