Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Fabio Eboli
Michael Tharp ha scritto: On 12/6/2012 4:26 AM, Fabio Eboli wrote: Are you using the pll to obtain 72MHz (x9) for the clock? Yes, the crystal oscillator is multiplied up to 72MHz which then drives the timer. Even though the particular timer peripheral I chose happens to be on the APB1 bu

Re: [time-nuts] EIP545A 18GHz counter query

2012-12-07 Thread Chris Wilson
__ > This is where I am now, I hope the above makes some sense if > viewed with the service manual and the schematics. Thanks. 07/12/2012 10:17 Latest update: Removed Q12 from board A109 and put a 1k resistor across vacant emit

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Bob Camp
Hi To make things play nice, you would like to have the timer counters reset at a specified point. That way the math all works out nicely. Bob On Dec 7, 2012, at 12:18 AM, Hal Murray wrote: > > li...@rtty.us said: >> That would be an input capture rather than an interrupt. > > Thanks. Yes,

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Bob Camp
Hi You are driving an integrator (the OCXO). You want a very stable voltage on the EFC to get the loop to close. A PWM is as simple a model for a 1 bit D/A as any. One bit A/D's are a feedback on a 1 bit D/A. You do some stuff to move the noise around and to get it all to work. Bob On Dec 7

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Bob Camp
Hi In this case it's very much a "you get what you pay for" sort of thing. You are indeed comparing an hourglass to a cesium standard. Bob On Dec 7, 2012, at 2:20 AM, "Don Latham" wrote: > Good thought, Bob. AD9548 $27, eval board a whopping $250, get a > thunderbolt :-). The eval board has a

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Bob Camp
Hi I believe your second counter (the one that starts on one edge and stops on the other) will have trouble. It is unlikely you will get your 14 ns resolution out of it. The analog TDC is a fine idea. Cheap, easy, and requires a few parts that are not built into the micro controller. The simpl

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Bob Camp
Hi That is an impressive hourglass. In the context of the thought experiment "swap offer" - no, mine is not a work of art. It's only value is as a time keeper. Bob On Dec 6, 2012, at 10:37 PM, DaveH wrote: > If you had an Ikepod, I might be interested. > > http://www.ablogtowatch.com/ikepod

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Fabio Eboli
Bob Camp ha scritto: Hi I believe your second counter (the one that starts on one edge and stops on the other) will have trouble. It is unlikely you will get your 14 ns resolution out of it. Are you thinking to sync logic inside the device or other problems? (not considering "defects" li

Re: [time-nuts] PTTI 2012, part 3/3

2012-12-07 Thread W2GPS
Paul, Regarding SSR-Pricing, Synergy said they will make the new SSR-6Tr timing board available at $35 FOB San Diego (about half the $69.85 commercial price) for educational pursuits which include Ham radio, educational institutions, experimenters, etc. (limit one part per customer). For compariso

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Fabio Eboli
Fabio Eboli ha scritto: Bob Camp ha scritto: The analog TDC is a fine idea. Cheap, easy, Easy for many, not for me. This is why I like the idea to play with the TAC, I have very Here I'm using TAC and TDC for the same meaning... little experience with such high speed stuff, it's like

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Jim Lux
On 12/6/12 1:56 PM, Bob Camp wrote: Hi The single best thing about a TBolt is Lady Heather. Consider how many years it's taken to get it to where it is today. Consider how many people have worked extensively on it. It's a wonderful thing to have available. Could you make a homebrew gizmo look

Re: [time-nuts] EIP545A 18GHz counter query

2012-12-07 Thread paul swed
Chris So you also must run the gatesgarth website. I was thinking there might be other good tidbits. The EIP manual was nice. Good job on the control signal. I had a chance to reread the theory of operation yesterday (Well parts) and if band 2 is now working by cheating at least, then it would be i

Re: [time-nuts] Open source

2012-12-07 Thread Scott McGrath
GPL and Open Source are frequently confused technically any code where the source code is available to the customer is open source. As in open for inspection, under terms agreed to in the license. What most people think about when they hear about open source is code released under variants of

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Jim Lux
On 12/6/12 11:12 PM, Hal Murray wrote: Suppose you just implement a simple bang-bang control. Suppose the EFC is 1 volt and the frequency is correct but the GPSDO phase is a bit early relative to the GPS PPS. So the FF says early and the software says go-faster. That keeps happening for a

Re: [time-nuts] GPSDO Alternatives (GLUE)

2012-12-07 Thread Jim Lux
On 12/6/12 5:01 PM, Bob Camp wrote: Hi The solution to the problem is well known in several forms. Cost is below $5 for pretty much all of them. No need to re-invent the wheel. The gotcha is that you can't do it 100% with internal CPU peripherals. You will need *some* glue. I think that's th

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Jim Lux
On 12/6/12 11:20 PM, Don Latham wrote: Good thought, Bob. AD9548 $27, eval board a whopping $250, get a thunderbolt :-). The eval board has a lot of SMA's on it... This is a general problem with eval boards these days.. They provide a lot of functionality on the board to make it easy to evalu

Re: [time-nuts] PTTI 2012, part 3/3

2012-12-07 Thread paul swed
Thanks I will try this out. Pretty darn interesting indeed and at $35. Great. Thats my kind O price. Regards Paul WB8TSL On Fri, Dec 7, 2012 at 8:39 AM, W2GPS wrote: > Paul, > > Regarding SSR-Pricing, Synergy said they will make the new SSR-6Tr timing > board > available at $35 FOB San Diego (ab

Re: [time-nuts] GPSDO Alternatives (GLUE)

2012-12-07 Thread paul swed
Jim right on target for my 2 cents, Simple is often hard. Regards Paul WB8TSL On Fri, Dec 7, 2012 at 10:12 AM, Jim Lux wrote: > On 12/6/12 5:01 PM, Bob Camp wrote: > >> Hi >> >> The solution to the problem is well known in several forms. Cost is below >> $5 for pretty much all of them. No need t

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Bob Camp
Hi Without some qualifier on "how good", we all will be talking about hourglasses and cesium standards at the same time. That makes sorting things out a bit difficult. It may get you into building a "controlled hourglass" that's less accurate than a free running $10 wrist watch. So far the only

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Tom Miller
And then it becomes popular and guess what happens to the price? Tom - Original Message - From: "Bob Camp" To: "'Discussion of precise time and frequency measurement'" Sent: Friday, December 07, 2012 12:15 PM Subject: Re: [time-nuts] GPSDO Alternatives To "win" the hourglass vs c

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Don Latham
but we could use a less expensive one. a simple light interruptor senses the end of flow, a robust servo turns over the hourglass for the next cycle. our favorite arduino counts seconds from the gps, and adjusts the turnover appropriately. If magnetite sand is used, an external magnetic field can p

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread paul swed
Bob Yes would agree these are the attributes of a solution thats interesting. Numbers of folks have created solutions over the years. But the reference architecture should be as good as or better then the tried and true tool we have like the HP 38XX or Tbolt. Otherwise is just another GPSDO. Regard

[time-nuts] Pictures of inside of a 5061A Cesium tube ?

2012-12-07 Thread Pete Lancashire
Has anyone posted pictures of what a dissembled 5061A tube looks like ? Just curious -pete ___ 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.

Re: [time-nuts] Pictures of inside of a 5061A Cesium tube ?

2012-12-07 Thread Tom Van Baak
Hi Pete, Corby might have some. He's disassembled many Cs tubes. I'll look for my old photos too. Meanwhile here's a collection of several Cs tubes: http://www.leapsecond.com/images/cs-cavity-collection-2.jpg It the main "cavity" through which the Cs atoms fly while getting exposed to the magic

Re: [time-nuts] Pictures of inside of a 5061A Cesium tube ?

2012-12-07 Thread Brooke Clarke
Hi Pete: Try Google Images. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Pete Lancashire wrote: Has anyone posted pictures of what a dissembled 5061A tube looks like ? Just curious -pete ___ time

Re: [time-nuts] Open source

2012-12-07 Thread David Kirkby
On 7 December 2012 15:00, Scott McGrath wrote:> > What most people think about when they hear about open source is code > released under variants of the GPL which require that code released to the > public built with GPL tools be made available for no more than the cost of > distribution ie yo

Re: [time-nuts] Open source

2012-12-07 Thread Scott McGrath
that was my point code is open source means open for inspection by end-user. The tool chain is irrelevant unless it comes from GPL or similar licenses. Back in the mainframe days most code was proprietary but distributed to customer in the form of source code to be compiled by the end user.

Re: [time-nuts] Open source

2012-12-07 Thread Mike S
On 12/7/2012 4:08 PM, Scott McGrath wrote: that was my point code is open source means open for inspection by end-user. The tool chain is irrelevant unless it comes from GPL or similar licenses. Back in the mainframe days most code was proprietary but distributed to customer in the form of so

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Bob Camp
Hi At least one should compare similar to better than approaches. This is a multi year design. Pick a goal first, then try to fit a specific approach to the goal. If the approach makes sense, move on with the design. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-n

Re: [time-nuts] Open source

2012-12-07 Thread gary
Not by the most commonly accepted definition: http://opensource.org/docs/osd The no discrimination clause is interesting. That explains the bizarre "white power" linux distribution. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go

Re: [time-nuts] Open source

2012-12-07 Thread Scott McGrath
Well the GPL crowd has kind of conflated open source with code licensed under the GPL. And yes I have met Richard Stallman on many occasions. And I'm sure he would also disagree on my definition of open source Heck under those terms code released under the BSD license does not qualify as 'open

Re: [time-nuts] Termination talk

2012-12-07 Thread Magnus Danielson
On 11/28/2012 11:52 PM, M. Simon wrote: I was going to post an anecdote about termination to the list and then thought that the piece would make a great column. It did. My magazine featured it in one of its daily mailings. If you want to check it out: http://www.ecnmag.com/blogs/2012/11/long-l

Re: [time-nuts] Open source

2012-12-07 Thread Mike S
On 12/7/2012 5:26 PM, Scott McGrath wrote: Well the GPL crowd has kind of conflated open source with code licensed under the GPL. And yes I have met Richard Stallman on many occasions. And I'm sure he would also disagree on my definition of open source You're confusing the two. Stallman promot

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread Charles P. Steinmetz
John wrote: What's *really* interesting, though, is the idea that collectively we might develop some standard measurement protocols that would be reproducible in a number of (amateur) labs. I agree, but I didn't dare to dream so large when I wrote: From my perspective, the most interesting

Re: [time-nuts] PTTI 2012, part 3/3

2012-12-07 Thread paul swed
They did respond back and I am limited to 1. Wanted 2 but such is life. :-) Will order most likely Monday. Regards Paul WB8TSL On Fri, Dec 7, 2012 at 11:45 AM, paul swed wrote: > Thanks I will try this out. Pretty darn interesting indeed and at $35. > Great. Thats my kind O price. > Regards > Pa

Re: [time-nuts] Open source

2012-12-07 Thread Chris Albertson
Yes, GPL is just one of many Open Source license types. Others include 1) GPL (may only be used for other GPL'd projects) 2) "BSD" style (allows use for any purpose, buy you can't sue the author) 3) Public Domain (totally unrestricted use) 4) Various Creative Commons versions some allow comercial

Re: [time-nuts] EIP545A 18GHz counter query

2012-12-07 Thread paul swed
Did do some more reading and I think what I suggest is the right approach. Band 2 and 3 use the same VCO. So if band 2 is generally working then its possibly the rf multiplier yig filter mixer diodes etc. But if the RF detectors show RF then its going to be a much more interesting issue. I do not k

Re: [time-nuts] GPSDO Alternatives - Bert's boards

2012-12-07 Thread WB6BNQ
Hello Bert, The boards look nice but tell me nothing of the circuitry. How about sending the schematics ?? That way I can appreciate what it is that you have. BillWB6BNQ p.s. By the way, what ever happen with that DMTD you were going to produce about three years ago ? ewkeh...@aol.com

Re: [time-nuts] PPS offset between GPS receivers

2012-12-07 Thread Chris Albertson
One more test to try. Connect one PPS signal to both GPIO ports and see how close to zero offset you get. It would likely be random which gets read first. On Wed, Dec 5, 2012 at 5:37 AM, Gabs Ricalde wrote: > Hi everyone, > > As Tom suggested, I redid the test with less than 1 ft. of wire fr

Re: [time-nuts] GPSDO Alternatives

2012-12-07 Thread David
On Fri, 07 Dec 2012 17:50:55 -0500, "Charles P. Steinmetz" wrote: >John wrote: > >>What's *really* interesting, though, is the idea that collectively >>we might develop some standard measurement protocols that would be >>reproducible in a number of (amateur) labs. > >I agree, but I didn't dare

Re: [time-nuts] PPS offset between GPS receivers

2012-12-07 Thread Bob Camp
Hi A lot depends on exactly what the interrupt structure is. It may also depend on the phase of the cpu clock relative to the pps signal. What's reasonably sure is that there is indeed some offset between the two where the answer is indeed "ft's" random. Another thing to check - how wide is the