Re: [time-nuts] FS700 manual
Hi Mikael, Many thanks for the offer of the photos. I'm in no immediate panic, I'm not expecting to have my hands on the FS700 itself for another week or so, but if I haven't located any scans in the meantime that would be very much appreciated. Regards Nigel GM8PZR In a message dated 20/04/2014 20:08:45 GMT Daylight Time, mi...@neptuni.se writes: Hi all, I have a papermanual for the FS700, but I havn't scanned it yet, I could send some photos of the schematics to you Nigel if you want, to start with. Best Regards, Mikael Alexandersson ___ 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. ___ 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] FS700 Loran-C Frequency Standard Schematics
Now there's an interesting part number for a scanner:-) I've had similar problems in the past trying to stitch schematics, I did find a program some years ago that would half work, usually matching up the ends of the lines ok, but then leaving quite significant distortion in that region. I know others have claimed some success so thought perhaps it was just me, but perhaps not after all. These days I use a Kodak feed through unit that will take up to A3, and with sheets even larger than that it generally manages in two or more A3 parts with a generous overlap which isn't too bad, so would be quite happy to do the scanning here if I had access to a copy. I'd be more than happy to pay the postage charges both ways if anyone could make a copy available for scanning, and happy to share the results, but must admit if it were my copy I'd probably be pretty reluctant to trust it to the post. Regards Nigel GM8PZR In a message dated 20/04/2014 20:09:08 GMT Daylight Time, mag...@rubidium.dyndns.org writes: Nigel, On 04/20/2014 03:43 PM, gandal...@aol.com wrote: Hi Magnus Thanks for the reply. I was aware of that, and the $35 previously mentioned in the time-nuts archives for an original manual from SRS doesn't sound too bad, but they don't seem to list the FS700 these days and for some other kit they now have the manuals priced at $100 each. I was hoping to find a less expensive option:-) Let's see if there is a scanner available to handle the fold-outs. My HP5370C scanner (read that number once more!) doesn't do that size and I have not figured out a good way to have schematics partially scanned and joined together. The one program, hugin, that seems to join photos doesn't work with scanned schematics. Cheers, Magnus ___ 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. ___ 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] optically excite a quartz crystal?
On Mon, 21 Apr 2014 17:12:54 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Optical excitation of quartz resonators: Electronics Letters http://digital-library.theiet.org/content/journals/el, Volume 18, Issue 9 http://digital-library.theiet.org/content/journals/el/18/9, 29 April 1982, p. 381 – 382 Thanks Bruce! For those who dont want to buy the paper, here a short summary: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal Attila Kinali -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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] optically excite a quartz crystal?
On 04/21/2014 11:40 AM, Attila Kinali wrote: On Mon, 21 Apr 2014 17:12:54 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Optical excitation of quartz resonators: Electronics Letters http://digital-library.theiet.org/content/journals/el, Volume 18, Issue 9 http://digital-library.theiet.org/content/journals/el/18/9, 29 April 1982, p. 381 – 382 Thanks Bruce! For those who dont want to buy the paper, here a short summary: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? Cheers, Magnus ___ 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] optically excite a quartz crystal?
I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
In my over 50 years of active ham radio experience as well as in my professional one, I have literally taken apart 10s of thousands of crystals, and, have never seen a single on where there has not been a physical contact with the quartz. That of course includes the most common FT-243. Regards - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Sunday, April 20, 2014 9:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] optically excite a quartz crystal? Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
Hi If you look closely at most of them, the plates are not flat. They are higher on the edges than in the center. There’s a gap in the middle. If you don’t have the gap, the blank is constrained by the big heavy plate. That damps the resonance and lowers the Q. Bob On Apr 21, 2014, at 9:00 AM, Chuck Harris cfhar...@erols.com wrote: I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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] optically excite a quartz crystal?
On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Attila Kinali -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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] optically excite a quartz crystal?
Agree there are some like that, but, only a few. A large spring loaded plate is not going to dampen a piece of quartz vibrating in the MHz range at all. Granted, the sealed, and metalized construction is a better one, but it is mostly done to minimize shock and impurities. - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Monday, April 21, 2014 9:17 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] optically excite a quartz crystal? Hi If you look closely at most of them, the plates are not flat. They are higher on the edges than in the center. There's a gap in the middle. If you don't have the gap, the blank is constrained by the big heavy plate. That damps the resonance and lowers the Q. Bob On Apr 21, 2014, at 9:00 AM, Chuck Harris cfhar...@erols.com wrote: I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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. ___ 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] optically excite a quartz crystal?
Hi One of the reasons for going to plated electrodes was to control the damping on the resonator. You control plating thickness fairly tightly for this reason. A great big lump of iron on your vibrating area does indeed damp it. Bob On Apr 21, 2014, at 9:29 AM, Mike Feher mfe...@eozinc.com wrote: Agree there are some like that, but, only a few. A large spring loaded plate is not going to dampen a piece of quartz vibrating in the MHz range at all. Granted, the sealed, and metalized construction is a better one, but it is mostly done to minimize shock and impurities. - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Monday, April 21, 2014 9:17 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] optically excite a quartz crystal? Hi If you look closely at most of them, the plates are not flat. They are higher on the edges than in the center. There's a gap in the middle. If you don't have the gap, the blank is constrained by the big heavy plate. That damps the resonance and lowers the Q. Bob On Apr 21, 2014, at 9:00 AM, Chuck Harris cfhar...@erols.com wrote: I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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. ___ 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. ___ 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] optically excite a quartz crystal?
On 04/21/2014 03:18 PM, Attila Kinali wrote: On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Cool. Today we use semiconductor lasers that we can modulate directly, so no need for the AOM on the NeHe laser. Cheers, Magnus ___ 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] optically excite a quartz crystal?
Hi If you are going to thermally excite the resonator, and measure the resonance optically, there’s no reason at all to use quartz. There are other materials with much higher acoustic Q than quartz. Bob On Apr 21, 2014, at 9:47 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 04/21/2014 03:18 PM, Attila Kinali wrote: On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Cool. Today we use semiconductor lasers that we can modulate directly, so no need for the AOM on the NeHe laser. Cheers, Magnus ___ 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. ___ 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] optically excite a quartz crystal?
No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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] optically excite a quartz crystal?
Hi Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. Ammonium bi-flouride and water was the most common etchant in that era. There are a number of papers about the whole deal in the FCS, and many stories told by those who were part of the changes. Bob On Apr 21, 2014, at 10:10 AM, J. Forster j...@quikus.com wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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. ___ 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] optically excite a quartz crystal?
In message a5032606-d7d7-4231-b1bd-434670274...@rtty.us, Bob Camp writes: Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. The story is slightly more interesting than that: Blileys crystals were almost totally without these problems, but they wouldn't tell why that might be. In the end the government put a lot of pressure on Bliley to squeeze out the manufacturing secret. The secret was etching. To keep it secret, Bliley had called it something along the lines of X-Grind and not applied for a patent. The Government forced Bliley to share the etching secret without giving any compensation, and the Blileys were bitter about that for the rest of their lifes. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] optically excite a quartz crystal?
Who said they were plated? -Chuck Harris J. Forster wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris ___ 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] optically excite a quartz crystal?
The etching referred to was by post-war hams, -John === Hi Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. Ammonium bi-flouride and water was the most common etchant in that era. There are a number of papers about the whole deal in the FCS, and many stories told by those who were part of the changes. Bob On Apr 21, 2014, at 10:10 AM, J. Forster j...@quikus.com wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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. ___ 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. ___ 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] optically excite a quartz crystal?
Hi As with all “good stories” there are many versions told by many people. I’ve heard far to many mutually contradictory versions to have any real idea what’s true. You are correct that etching was a known process in the 1930’s and that it had been used by various people at various times. Since it added time (and complexity) to the process, it got dropped by most people to speed up production … Bob On Apr 21, 2014, at 10:51 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message a5032606-d7d7-4231-b1bd-434670274...@rtty.us, Bob Camp writes: Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. The story is slightly more interesting than that: Blileys crystals were almost totally without these problems, but they wouldn't tell why that might be. In the end the government put a lot of pressure on Bliley to squeeze out the manufacturing secret. The secret was etching. To keep it secret, Bliley had called it something along the lines of X-Grind and not applied for a patent. The Government forced Bliley to share the etching secret without giving any compensation, and the Blileys were bitter about that for the rest of their lifes. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] optically excite a quartz crystal?
Hi Well I can name at least one post war ham (me at age 14) who did not understand the need for etch after grinding… Bob On Apr 21, 2014, at 11:21 AM, J. Forster j...@quikus.com wrote: The etching referred to was by post-war hams, -John === Hi Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. Ammonium bi-flouride and water was the most common etchant in that era. There are a number of papers about the whole deal in the FCS, and many stories told by those who were part of the changes. Bob On Apr 21, 2014, at 10:10 AM, J. Forster j...@quikus.com wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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. ___ 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. ___ 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. ___ 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] optically excite a quartz crystal?
Bob, We all start somewhere. Today one buys aged equipment with fancy synthesis so that fooling around with crystals, etching or graphiting them won't be necessary. Hell, someone taking the time to calibrate their transceiver is rare these days. Cheers, Magnus ___ 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] optically excite a quartz crystal?
When this question was first posed, AOM's first jumped to my mind. An AOM (sometimes AOD) is an Acousto-Optic Modulator that works by setting up an acoustic wave in a crystal. When a laser is directed through (or reflected by) an AOM, it is deflected. One way to think about this is the crystal lattice deforms with the period of the acoustic wave. The lattice deformations form a grating of regions of varying indices of refraction which produce varying phase delay. This steers the beam just as a grating would. Another way of thinking about it is the 'phonon's' momentum and the photon's momentum add producing a deflection (like two billiard balls colliding). This might seem impossible, but the math works out exactly.. Another nice thing is, if you recall, the EM field produced in the far-field of a coherent EM wave impinging on a grating is the Fourier Transform of the grating itself. In something like a CD, the grating has hard edges, producing lots of harmonic content. AOMs look like sine waves, most of the energy ends up in the deflected beam. AOMs are often constructed using quartz crystals because they are fairly broadband (optically) and piezoelectric. The piezoelectric properties make it easy to set up the acoustic wave in the crystal. The key difference is, AOMs are typically designed to absorb as little power as possible (power absorption is their primary failure mechanism). Depending on your laser, you might want to find an AOM that is less transparent in your excitation regime. That said, you can get a lot of energy out of lasers these days. Megawatt pulses are not impossible with something like a Kerr-lens mode locked laser. This results in extremely high electric fields (MW pulse in 0.1 mm^2). Andy Bardagjy bardagjy.com On Apr 21, 2014, at 6:47 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 04/21/2014 03:18 PM, Attila Kinali wrote: On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Cool. Today we use semiconductor lasers that we can modulate directly, so no need for the AOM on the NeHe laser. Cheers, Magnus ___ 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. ___ 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] time-nuts Digest, Vol 117, Issue 80
The FT-243 holders I revamped in the 1950s and 60s did have the aforementioned spring. However a close look at the electrode plates that contacted the quartz resonator had, in every case, a raised boss at each corner that spaced the center of the electrode a few mills above the center of the quartz. So the center part of the quartz was not restrained from moving. And it was not compressed by the spring. As I recall the stack up was lower electrode, quartz resonator (square in the case of the FT-243) upper electrode, edge seal with hole for the spring, the spring, and then the cover. I reworked quite a few of these at 8 MHz for use on the 2 meter band by multiplying by 18X. 8 x 18 = 144 MHz. Tooth paste moved them up and a small scratch with a bit of solder moved them down. Re: optically excite a quartz crystal? (Bob Camp) As for Bliley - go to the web site and if you look around, you can find a fascinating history of the company. It included details of the invention of the etch process and also of the rubber rock technique to vary the frequency of a crystal. They still make some of the best resonators for custom designed oscillators around. I used them last in a synthesizer design for a FAA customer VHF/UHF receiver only about 6 years ago. -73 john k6iql -Original Message- From: time-nuts-request time-nuts-requ...@febo.com To: time-nuts time-nuts@febo.com Sent: Mon, Apr 21, 2014 11:00 am Subject: time-nuts Digest, Vol 117, Issue 80 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: optically excite a quartz crystal? (Bob Camp) 2. Re: optically excite a quartz crystal? (Bob Camp) -- Message: 1 Date: Mon, 21 Apr 2014 11:24:43 -0400 From: Bob Camp li...@rtty.us To: Poul-Henning Kamp p...@phk.freebsd.dk Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] optically excite a quartz crystal? Message-ID: 402dec2b-2405-493a-9866-31cc2ca88...@rtty.us Content-Type: text/plain; charset=windows-1252 Hi As with all ?good stories? there are many versions told by many people. I?ve heard far to many mutually contradictory versions to have any real idea what?s true. You are correct that etching was a known process in the 1930?s and that it had been used by various people at various times. Since it added time (and complexity) to the process, it got dropped by most people to speed up production ? Bob On Apr 21, 2014, at 10:51 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message a5032606-d7d7-4231-b1bd-434670274...@rtty.us, Bob Camp writes: Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. The story is slightly more interesting than that: Blileys crystals were almost totally without these problems, but they wouldn't tell why that might be. In the end the government put a lot of pressure on Bliley to squeeze out the manufacturing secret. The secret was etching. To keep it secret, Bliley had called it something along the lines of X-Grind and not applied for a patent. The Government forced Bliley to share the etching secret without giving any compensation, and the Blileys were bitter about that for the rest of their lifes. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. -- Message: 2 Date: Mon, 21 Apr 2014 11:26:16 -0400 From: Bob Camp li...@rtty.us To: j...@quikus.com, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] optically excite a quartz crystal? Message-ID: 6b374045-7b1f-4706-8b38-609b4366b...@rtty.us Content-Type: text/plain; charset=windows-1252 Hi Well I can name at least one post war ham (me at age 14) who did not understand the need for etch after grinding? Bob On Apr 21, 2014, at 11:21 AM, J. Forster
Re: [time-nuts] time-nuts Digest, Vol 117, Issue 80
Hi Yup, little high spots on the corners of the metal plates. Put the plates in “upside down” and the crystal stopped working …. — If you want to dig into the WWII stuff Virgil Bottom was always happy to talk about his role in saving the world by fixing the crystal process. There are a variety of stories told, some similar to his, some quite different. Yes beer was often involved during the story telling. Who knows what really happened ….. Bob On Apr 21, 2014, at 1:30 PM, johncr...@aol.com wrote: The FT-243 holders I revamped in the 1950s and 60s did have the aforementioned spring. However a close look at the electrode plates that contacted the quartz resonator had, in every case, a raised boss at each corner that spaced the center of the electrode a few mills above the center of the quartz. So the center part of the quartz was not restrained from moving. And it was not compressed by the spring. As I recall the stack up was lower electrode, quartz resonator (square in the case of the FT-243) upper electrode, edge seal with hole for the spring, the spring, and then the cover. I reworked quite a few of these at 8 MHz for use on the 2 meter band by multiplying by 18X. 8 x 18 = 144 MHz. Tooth paste moved them up and a small scratch with a bit of solder moved them down. Re: optically excite a quartz crystal? (Bob Camp) As for Bliley - go to the web site and if you look around, you can find a fascinating history of the company. It included details of the invention of the etch process and also of the rubber rock technique to vary the frequency of a crystal. They still make some of the best resonators for custom designed oscillators around. I used them last in a synthesizer design for a FAA customer VHF/UHF receiver only about 6 years ago. -73 john k6iql -Original Message- From: time-nuts-request time-nuts-requ...@febo.com To: time-nuts time-nuts@febo.com Sent: Mon, Apr 21, 2014 11:00 am Subject: time-nuts Digest, Vol 117, Issue 80 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: optically excite a quartz crystal? (Bob Camp) 2. Re: optically excite a quartz crystal? (Bob Camp) -- Message: 1 Date: Mon, 21 Apr 2014 11:24:43 -0400 From: Bob Camp li...@rtty.us To: Poul-Henning Kamp p...@phk.freebsd.dk Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] optically excite a quartz crystal? Message-ID: 402dec2b-2405-493a-9866-31cc2ca88...@rtty.us Content-Type: text/plain; charset=windows-1252 Hi As with all ?good stories? there are many versions told by many people. I?ve heard far to many mutually contradictory versions to have any real idea what?s true. You are correct that etching was a known process in the 1930?s and that it had been used by various people at various times. Since it added time (and complexity) to the process, it got dropped by most people to speed up production ? Bob On Apr 21, 2014, at 10:51 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message a5032606-d7d7-4231-b1bd-434670274...@rtty.us, Bob Camp writes: Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. The story is slightly more interesting than that: Blileys crystals were almost totally without these problems, but they wouldn't tell why that might be. In the end the government put a lot of pressure on Bliley to squeeze out the manufacturing secret. The secret was etching. To keep it secret, Bliley had called it something along the lines of X-Grind and not applied for a patent. The Government forced Bliley to share the etching secret without giving any compensation, and the Blileys were bitter about that for the rest of their lifes. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can
Re: [time-nuts] First success with very simple, very low cost GPSDO, under $8
Good afternoon very interested in the work you are doing with the STM board. As I mentioned far earlier in this thread I am attempting to use it to correct the BPSK WWVB signal here. Initial thoughts were using FORTH to program the STM board. Very curious what you are using as examples. My experience in FORTH is from many years ago and have done very poorly at C. But this may be the case to have something of interest to actually do. In either language. Regards Paul WB8TSL On Mon, Apr 14, 2014 at 12:27 PM, d0ct0r t...@patoka.org wrote: I was experimenting with the same setup for STM32 MCU. This microprocessor has accept the sine wave from external OCXO or GPSDO. No problem with this. The only thing: I was need to start MCU from slow watch crystal first. And then switch it to work to external one. In another case I got incorrect timing settings for MCU. Later, I decide to implement LTC6957-3 chip to share REFCLOCK source, since that chip has two equal CMOS-level outputs. Unfortunately I have no tool to measure the phase noise and jitters on each setup. It turns out all of this is built into the AVR chip. There is a counter and logic to copy the current counter value to a register on a PPS pulse raising edge.The counter keeps running and every second its value is trapped. I can connect the OCXO and the PPS directly to the AVR pin. The AVR has hardware (a fast comparator) to square a low amplitude sine wave and trap the counter on a zero crossing. So it looks like I can get rid of ALL of the external chips. The built in DAC is working well also but it needs some external resisters and caps. No need for '74 FFs or '373' or counter chips.I do get precision timing with no time critical software, no 74xxx chips. -- WBW, V.P. ___ 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. ___ 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] First success with very simple, very low cost GPSDO, under $8
Perhaps this thread should go off line not to distract from the originators thread. Regards Paul. On Mon, Apr 21, 2014 at 4:29 PM, paul swed paulsw...@gmail.com wrote: Good afternoon very interested in the work you are doing with the STM board. As I mentioned far earlier in this thread I am attempting to use it to correct the BPSK WWVB signal here. Initial thoughts were using FORTH to program the STM board. Very curious what you are using as examples. My experience in FORTH is from many years ago and have done very poorly at C. But this may be the case to have something of interest to actually do. In either language. Regards Paul WB8TSL On Mon, Apr 14, 2014 at 12:27 PM, d0ct0r t...@patoka.org wrote: I was experimenting with the same setup for STM32 MCU. This microprocessor has accept the sine wave from external OCXO or GPSDO. No problem with this. The only thing: I was need to start MCU from slow watch crystal first. And then switch it to work to external one. In another case I got incorrect timing settings for MCU. Later, I decide to implement LTC6957-3 chip to share REFCLOCK source, since that chip has two equal CMOS-level outputs. Unfortunately I have no tool to measure the phase noise and jitters on each setup. It turns out all of this is built into the AVR chip. There is a counter and logic to copy the current counter value to a register on a PPS pulse raising edge.The counter keeps running and every second its value is trapped. I can connect the OCXO and the PPS directly to the AVR pin. The AVR has hardware (a fast comparator) to square a low amplitude sine wave and trap the counter on a zero crossing. So it looks like I can get rid of ALL of the external chips. The built in DAC is working well also but it needs some external resisters and caps. No need for '74 FFs or '373' or counter chips.I do get precision timing with no time critical software, no 74xxx chips. -- WBW, V.P. ___ 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. ___ 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.
[time-nuts] BPSK Processing (was First success with very simple, very low cost GPSDO, under $8)
I just changed the thread title to BPSK Processing If you are having problems with the software what you need to do is start working on it in an easier environment. That would be some IDE like Eclipse on a standard desktop or notebook computer.You can feed your software made-up test data from a text file and send output to the screen. Get this working first them move to the target hardware.If you write in C there is better chance of (1) getting help and (2) finding a library to do most of what you want. But start here by listing (post to this thread) exactly what you expect to see as input and what output you'd like to generate. Seeing real numbers rather then some daulitative description is the first step. Post code examples and ask for advice. On Mon, Apr 21, 2014 at 1:29 PM, paul swed paulsw...@gmail.com wrote: Good afternoon very interested in the work you are doing with the STM board. As I mentioned far earlier in this thread I am attempting to use it to correct the BPSK WWVB signal here. Initial thoughts were using FORTH to program the STM board. Very curious what you are using as examples. My experience in FORTH is from many years ago and have done very poorly at C. But this may be the case to have something of interest to actually do. In either language. Regards Paul WB8TSL On Mon, Apr 14, 2014 at 12:27 PM, d0ct0r t...@patoka.org wrote: I was experimenting with the same setup for STM32 MCU. This microprocessor has accept the sine wave from external OCXO or GPSDO. No problem with this. The only thing: I was need to start MCU from slow watch crystal first. And then switch it to work to external one. In another case I got incorrect timing settings for MCU. Later, I decide to implement LTC6957-3 chip to share REFCLOCK source, since that chip has two equal CMOS-level outputs. Unfortunately I have no tool to measure the phase noise and jitters on each setup. It turns out all of this is built into the AVR chip. There is a counter and logic to copy the current counter value to a register on a PPS pulse raising edge.The counter keeps running and every second its value is trapped. I can connect the OCXO and the PPS directly to the AVR pin. The AVR has hardware (a fast comparator) to square a low amplitude sine wave and trap the counter on a zero crossing. So it looks like I can get rid of ALL of the external chips. The built in DAC is working well also but it needs some external resisters and caps. No need for '74 FFs or '373' or counter chips.I do get precision timing with no time critical software, no 74xxx chips. -- WBW, V.P. ___ 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. ___ 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. -- Chris Albertson Redondo Beach, California ___ 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] First success with very simple, very low cost GPSDO, under $8
Actually GCC supporting Cortex. So, I am using Raisonance IDE plus GCC Toolchain as a development environment. My current project functional diagram is following: +--- STM32 -- (Pulse Counter, TTL Generator, DDS driver, GPSDO monitor) GPSDO--LTC6957-3--| || | +--- AD9852 -- VFO - | | v +--- TADD3 -- (1PPS, TTL) -- As I'll finish it more or less, I'd like to compare the 1PPS which comes directly from GPSDO with 1PPS which I could create on MCU (and probably on DDS). As I mention before, each STM MCU comes with very useful Peripheral Library. That Library has tonnes of different examples. Regards, V.P. On 2014-04-21 16:29, paul swed wrote: Good afternoon very interested in the work you are doing with the STM board. As I mentioned far earlier in this thread I am attempting to use it to correct the BPSK WWVB signal here. Initial thoughts were using FORTH to program the STM board. Very curious what you are using as examples. My experience in FORTH is from many years ago and have done very poorly at C. But this may be the case to have something of interest to actually do. In either language. Regards Paul WB8TSL On Mon, Apr 14, 2014 at 12:27 PM, d0ct0r t...@patoka.org wrote: I was experimenting with the same setup for STM32 MCU. This microprocessor has accept the sine wave from external OCXO or GPSDO. No problem with this. The only thing: I was need to start MCU from slow watch crystal first. And then switch it to work to external one. In another case I got incorrect timing settings for MCU. Later, I decide to implement LTC6957-3 chip to share REFCLOCK source, since that chip has two equal CMOS-level outputs. Unfortunately I have no tool to measure the phase noise and jitters on each setup. It turns out all of this is built into the AVR chip. There is a counter and logic to copy the current counter value to a register on a PPS pulse raising edge. The counter keeps running and every second its value is trapped. I can connect the OCXO and the PPS directly to the AVR pin. The AVR has hardware (a fast comparator) to square a low amplitude sine wave and trap the counter on a zero crossing. So it looks like I can get rid of ALL of the external chips. The built in DAC is working well also but it needs some external resisters and caps. No need for '74 FFs or '373' or counter chips. I do get precision timing with no time critical software, no 74xxx chips. -- WBW, V.P. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] and follow the instructions there. Links: -- [1] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- WBW, V.P. ___ 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] BPSK Processing (was First success with very simple, very low cost GPSDO, under $8)
Will be travelling on business so will be out of touch next day or two. Regards Paul On Mon, Apr 21, 2014 at 7:35 PM, Chris Albertson albertson.ch...@gmail.comwrote: I just changed the thread title to BPSK Processing If you are having problems with the software what you need to do is start working on it in an easier environment. That would be some IDE like Eclipse on a standard desktop or notebook computer.You can feed your software made-up test data from a text file and send output to the screen. Get this working first them move to the target hardware.If you write in C there is better chance of (1) getting help and (2) finding a library to do most of what you want. But start here by listing (post to this thread) exactly what you expect to see as input and what output you'd like to generate. Seeing real numbers rather then some daulitative description is the first step. Post code examples and ask for advice. On Mon, Apr 21, 2014 at 1:29 PM, paul swed paulsw...@gmail.com wrote: Good afternoon very interested in the work you are doing with the STM board. As I mentioned far earlier in this thread I am attempting to use it to correct the BPSK WWVB signal here. Initial thoughts were using FORTH to program the STM board. Very curious what you are using as examples. My experience in FORTH is from many years ago and have done very poorly at C. But this may be the case to have something of interest to actually do. In either language. Regards Paul WB8TSL On Mon, Apr 14, 2014 at 12:27 PM, d0ct0r t...@patoka.org wrote: I was experimenting with the same setup for STM32 MCU. This microprocessor has accept the sine wave from external OCXO or GPSDO. No problem with this. The only thing: I was need to start MCU from slow watch crystal first. And then switch it to work to external one. In another case I got incorrect timing settings for MCU. Later, I decide to implement LTC6957-3 chip to share REFCLOCK source, since that chip has two equal CMOS-level outputs. Unfortunately I have no tool to measure the phase noise and jitters on each setup. It turns out all of this is built into the AVR chip. There is a counter and logic to copy the current counter value to a register on a PPS pulse raising edge.The counter keeps running and every second its value is trapped. I can connect the OCXO and the PPS directly to the AVR pin. The AVR has hardware (a fast comparator) to square a low amplitude sine wave and trap the counter on a zero crossing. So it looks like I can get rid of ALL of the external chips. The built in DAC is working well also but it needs some external resisters and caps. No need for '74 FFs or '373' or counter chips.I do get precision timing with no time critical software, no 74xxx chips. -- WBW, V.P. ___ 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. ___ 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. -- Chris Albertson Redondo Beach, California ___ 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. ___ 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.
