Re: [time-nuts] TBOLT communication
Nevil: In my business we use/ supply serial to parallel converters for programming our product originally designed for serial. We ran into most of the problems you have described. The hanging appears to be a windows problem (we use XL pro mostly). Ours uses the Prolific converter and driver. We found that there are signal voltage level problems associated with the use of the USB as power source. This appears to be much worse with laptops than with desktop computers. We can take the same 'setup' and move it from a non-functioning laptop connection, and make it work well on a desktop. Seems that for power savings the laptop makers are reducing current levels and voltage levels to the lowest values possible; thus not enough level out of the converter. An S-P converter with its own power supply should help if it is designed to up-convert the serial levels to RS 232 standards. One of the things we did to help this was to reduce the required serial levels in our product. Of course you cannot change the tunderbolt parameters. Since our cable must be computer powered, one of the things I have wanted to try (never enough time) is shift the serial signal up above ground by a small amount. Thought was to use a small button cell in the serial output line. Thus instead of the serial signal going from 0 to 3.5V, it would go from 1 to 4.5V or similar. My thought is that serial device logic does not actually require 0V for low logic state, and the extra volt on the high side would improve reliability of HI logic state. If you want to contact me off-line: buehl at superlink.net Tom Buehl At 06:58 PM 9/24/2008 +1000, you wrote: Hi, I have just spent a week or two trying to talk to a Trimble Thunderbolt. I have a laptop running VISTA, about which there is little to say. The laptop has no serial ports, but I have some USB/Serial converters that successfully run my HP 3815A and a Samsung GCRU/D, and also communicate with my HOBO loggers. The USB/Serial converters are a little difficult to use, sometimes hanging, necessitating unplugging and plugging back in. They get assigned to various Port numbers but tend to keep the same number from day to day. The ports can be configured in the management function. However the TBOLT refuses to talk to the converter, to the extent that I thought that I must have damaged the TBOLT. Today, as a last resort, I remembered an old PC, dragged it out and stoked it up, and to my delight the TBOLT monitoring program ran without difficulty under Windows 2000 with a conventional serial port. Now I vaguely remember talk about RS232 communications and the need for pull up or down resistors and supplies, but searching the archives I could find nothing relevant. Can anyone tell me how I could run the TBOLT off a USB/Serial converter? cheers, Neville Michie ___ 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] Odetics - Kobe Model 3100 TIA Manual ???
Emmanouil Sorry for delay, but took me a while to find where it was stored. I have a .pdf copy of the manual. Cna email if your server will accept 7 MB attachment. contact me off-line. buehl -at- superlink.net Tom Buehl At 09:21 PM 9/1/2008 +0300, you wrote: Hi I am searching for the Model 3000 TIA (Odetics / Kode) manual. Any idea ?? ___ 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 45, Issue 34
It looks like APC will provide software download for free from their website.. http://www.apcc.com/tools/download/index.cfmAt Tom Buehl 12:07 PM 4/18/2008 +1000, you wrote: Dennis, Ah-ha. Now here's the rub! I've got 2 such APC Smart UPS - but I cannot find, beg, borrow or steal a copy of the PowerChute software from anywhere. Does anyone have a copy lurking unwanted unloved in their 3.5 floppy cabinet ? Cheers, Kit VK2LL Message: 4 Date: Thu, 17 Apr 2008 17:26:18 -0700 From: Dennis Tillman [EMAIL PROTECTED] Subject: Re: [time-nuts] Power monitoring To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii snip These models went by the name 'Smart UPS'. The software, provided by APC, was called 'Power Chute'. Any company that made UPSes for servers had features like this and software to go with it. snip ___ 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 45, Issue 34
OOPS ! Cannot go directly to download page at APC. But from the 'failure' page which comes up, click SUPPORT at top; This gets you to http://www.apcc.com/support/index.cfm Then click SOFTWARE FIRMWARE in the SELF HELP column at left side. (in windows) Tom Buehl At 12:07 PM 4/18/2008 +1000, you wrote: Dennis, Ah-ha. Now here's the rub! I've got 2 such APC Smart UPS - but I cannot find, beg, borrow or steal a copy of the PowerChute software from anywhere. Does anyone have a copy lurking unwanted unloved in their 3.5 floppy cabinet ? Cheers, Kit VK2LL Message: 4 Date: Thu, 17 Apr 2008 17:26:18 -0700 From: Dennis Tillman [EMAIL PROTECTED] Subject: Re: [time-nuts] Power monitoring To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii snip These models went by the name 'Smart UPS'. The software, provided by APC, was called 'Power Chute'. Any company that made UPSes for servers had features like this and software to go with it. snip ___ 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] WG: EZGPIB other software
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY I received both of UBs original messages, and also RKs reply in the odd typeface. I think I recognize this as foreign language character encoding (not sure which language). I exchange Chinese often, and is quite similat looking until decoded (language package installed). Tom Buehl At 04:39 PM 8/21/2007 +0200, you wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Friends, because I received the first of my messages completely garbled as Rob díd, I send it a second time and received it ok. The second message includes a in front of every line, the original not. I am not aware how this can happen but it is already the second time that i experience this problem. Best regards Ulrich -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Alberto di Bene Gesendet: Dienstag, 21. August 2007 15:22 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] WG: EZGPIB other software ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Rob Kimberley wrote: Ulrich, Not sure what you did, but this is how I received your message below.. Rob Kimberley -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ulrich Bangert Sent: 21 August 2007 13:49 To: Time nuts Subject: [time-nuts] WG: EZGPIB other software H1?dn?*'u?ijw^v?j[??®??¶)???ln?§q?[EMAIL PROTECTED] \\[??H?H??JH?]???V?P\]Z[X?H??^Y\Y?[ ??HH]??YH[\X?[?? ???H?H??YH??SP???[???H[??X?\X[??\??\?H???[YP ?[??Z?H[??X??[?H[??Z[?] ?P??H??]H?H??Y\?X??\?[[?[K?]???Y YY??H[?Z[]??^ [?[H?XZH\?] ?H?\H?Y?H\?N H??\?[??[H???\K???\?\]Z[X?H\???Y? ???\Y??]X?K??[???Z?[ ??[X?^\??[???Y???[?\?? ?[?\ ?BY?B??\[\?[K[] X[??\ H[Y[???X???B?[?XK?KX[?XZX??\?[???[Y[??[?? ?H[?\? Here the message from Ulrich arrived in perfect shape. To be honest two copies of it... 73 Alberto I2PHD ___ 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] OT: Not pendulums or atomic clocks or gravity
Try this low tech analysis on for size. Inertia at work: The ball is elastic and compresses sufficiently that all the kenetic energy is changed into potential energy; Center of mass having moved only slightly due to inertia. At this time the compression is concentrated between the center of mass and the face of the club, along a line normal to the surface. This potential energy is then converted back into motion (kenetic energy) and the direction of this motion is normal to the club surface. Very different than a light beam or wavefront reflecting off of a surface. Tom Buehl At 08:43 PM 5/29/2007 -0700, you wrote: The angle of incidence is relative to the surface normal, not the surface itself. It's 0 degrees as the club face contacts the ball, not 45. -- john, KE5FX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Palfreyman, Jim L Sent: Tuesday, May 29, 2007 8:36 PM To: time-nuts@febo.com Subject: [time-nuts] OT: Not pendulums or atomic clocks or gravity Since you have all enjoyed this discussion on rotating non-inertial frames of reference so much, here's another one for you. In golf, a typical pitching wedge has an angle of 45 degrees. Since angle of incidence equals angle of reflection why doesn't the ball bounce off the club, go straight up and hit you in the face? (A good golfer would hit it 100m.) Jim Palfreyman ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OT: eBay bidding question
When I asked these questions of eBay; the unsatisfactory answer was that only actual bids show. This meaning a new bid submmitted would create new/ additional line, similar to the series of bids on April 23. Is not clear why this bidder put in so many bids within two minutes, since no other bidder's 'proxy' bid shows as exceeding any of his bids. Also does not explain following: Bidder six placed bid on April 22, but his bid does not show until after many other bids are placed on 23, 24, and 25 April. It is expected he would show as a bidder if his bid was 4,000. If his bid was less, then he would have needed to bid again; which eBay says would result in the new bid submission being displayed. Tom Buehl At 03:17 PM 4/26/2007, you wrote: In a message dated 4/26/2007 05:23:48 Pacific Daylight Time, [EMAIL PROTECTED] writes: Can anyone propose a sequence of bids on dates that explains this list of recorded bids and dates? I guess there must be one but it is evading me. *Bidder*Bid AmountDate of bid Bidder 6US $4,000.00 Apr-22-07 05:14:15 Bidder 8US $4,000.00 Apr-25-07 00:49:30 Could this be because of bid retractions or simply revising a bid? Are the times/dates local time or Ebay UTC? bye, Said ** See what's free at http://www.aol.com. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OT: Audiophoolery
Rasputin: As a lover of fine kitchen knives, I can appreciate your decision. And of course there is the 'time nut' measurable advantage of time per slice, for a ripe cucumber, being only 42.467 mS instead of the typical 43.125 mS. Tom At 08:18 AM 4/20/2007, you wrote: Well, stupid may not be the right word. It seems to be human nature to want to be part of a group that is somehow better than other groups. That actually had some evolutionary survival value at one time. Groups form all the time - religious, political, technical, even time-nuts. Some of the things they believe do not seem rational. Audiophiles are just another group, but the membership dues are kind of high. You can also see how the group has been manipulated by predators to increasing heights of expensive fantasies. There are parallels in religion and politics. Again, it's human nature. Surely, there's no one in this group that has bought an expensive instrument just to keep up with the group. Hmm. ...and I just bought a set of three Chef's knives for my kitchen for $500. /b __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit
At 10:25 AM 12/20/2006, you wrote: Hello folks, The controller's task is to always pour just enough fluid from the second pot into the first pot to keep the fluid level constant despite the fluid lost through the small hole. One refinement of the model is that we also consider that the amount of fluid pouring out of the hole shall not only depend on the hole's size but also on the fluid level itself inside the pot as well as the surrounding's temperature for which there is no good counterpart in the model. The model for the surounding temperature is a larger pot with a fluid level which is lower than the level in the oven pot. Flow rate is dependent on the difference in the fluid levels, with the oven loosing less heat when the 'outside' pot is at a higher level. (higher temperature) Tom Buehl ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Re Danjon Astrolabe
Hi all: Robert's pinching an idea from the early - - brings to mind what we did in the early days of video/ TV. Hope this inspires some useful ideas. To measure spot size on CRT, a small slit was placed against the TV or oscilloscope screen and a photo sensor measured the light intensity coming through the slit. As the circular spot entered the slit, the change in light intensity increased; and as it left the slit light intensity decreased. If the slit was wide, the photo detector output has a sine wave rising edge, a flat top, and a sine wave falling edge. If the slit was very narrow, there is no flat top. If we use the slit to watch the sun, we have the equivelent of a pinhole camera with only one direction of focus. Making a structure with 2 photodetectors, or 3 as TVB suggests, and carefully place such that one is on each edge of the image. As one outputs a rising edge, the other outputs a falling edge. In theory, when properly positioned, both photodetectors will have equal output when the sun image is exactly between photodetectors. This is also the point of greatet rate of change. This is equal to the inverse of the fine wire gnomon mentioned by TVB. Simple detection would be using a comparitor or zero crossing detector. You get one output as the sun approaches the center, and switches as the sun image crosses center. Any offset or inacruacy would be identical day to day, so the time interval is repeatable. This should be very simple to build. As a computerized approach, each output could be converted with an A to D and mathematically analyzed. The ultimate refinement would be a linear array, such as that used in a scanner. If you can get the image to pass over a linear array with 4,000 pixels within 3 seconds, this would allow calculating time verses position at the rate of less than 1 millisecond per pixel. Accuracy could be increased by making the distance from the slit to the detector greater (increasing the size of the pinhole camera image and increasing the rate of travel across the sensor), or making the slit smaller, or making the detector diameter smaller. Using a piece of fiberoptics connected to photodiode makes the detection diamater equal to the fiber. I have had good results attaching one end of cheap plastic fiber to tip of photodiode with clear glue or epoxy. Cheap plastic fiber like that used in decorative lamps, or experimentor type sold by Radio Shack, will also pass IR for short distances. One source of inacuracy is when a sloud only shades one edge of the sun. I suspect the IR image of the sun is more precise than the visible image, because defraction (tildel effect) is less when passing through clouds. Since a slit provides only one direction of movement, proper angular positioning of the slit would minimise changes in the suns orbit from day to day, week to week. Would like to hear comments from those amoung you having greater expertise in designing such a device. Tom Buehl EFFECTIVE SOLUTIONS At 03:27 AM 9/29/2006, you wrote: How about pinching an idea from the early radar and missile technologies - Conical Scanning. Basically you offset the detector of feed antenna from the point of focus and then rotate it. If the signal is off centre you get sinusoidal modulation of the signal. The phase of the modulation tells the antenna steering what direction to move to get back on target. A practical solution is to angle and spin the secondary mirror of a reflecting (e.g. cassegrain) telescope. A index sensor gives you your phase reference. Robert G8RPI. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dr Bruce Griffiths Sent: 29 September 2006 01:09 To: Tom Van Baak; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Re Danjon Astrolabe Tom Van Baak wrote: The scheme probably needs three photocells to be sure that the one in the middle is darker than the others. Might be able to mask it with a slit and use a fine wire gnomon, in a coarse/fine servo. Could use a variable frequency motor and precision reduction, like a phonograph turntable only much slower. SNIP Whilst the resolution may be good, the accuracy of an open loop microstepped stepper motor isn't that great. Its usually worse than when not using microstepping. Variations in friction torque on the motor will also dramatically affect its positioning accuracy. A high resolution position encoder mounted on the sundial base is essential if you need to accurately determine its direction. Servomotors with encoder feedback will achieve a much higher performance than a stepper motor. If gears or rollers are used then backlash in gears or microcreep in rollers will reduce the positioning accuracy. The sundial base bearing runout can also affect positioning accuracy. The equivalent time error is not likely to be much smaller than a few seconds at best Bruce
Re: [time-nuts] caveat emptor: eBay tm seller warning
Christopher: I got my money back, 100%, on a $700 TEK spectrum analyzer. Took several/ many phone calls over several weeks, including several check's in the mail answers. His number is 714-778-5151. Kyong Joon (Joon is first name like the month June). Heavy Korean accent, and perhaps some language limitations. His eBay guy is Samuel, a part timer, college student. If you are not in USA, I would be glad to call for you, as many of the 'nuts' would also be. Expect that after the 36 th call (or 136 th), he will be anxious to send your refund. There may be more that can be done; Contact me off lis. Tom Buehl [EMAIL PROTECTED] At 11:13 PM 7/17/2006, you wrote: Folks, Heads up on this eBay seller: Test Equipment Surplus, eBay id http://pics.ebaystatic.com/aw/pics/s.gif http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedbackuserid=jtseleii d=7614062550frm=284ssPageName=VIP:feedback:1:us jtsele, aka [EMAIL PROTECTED] aka Joon Kyong. Although I have satisfactorily done business with him on eBay several times, I got ripped off in my last transaction. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] IC for 1 PPS Output
HI everyone: last year I did a design requiring a full 5V out (higher than TTL) into 50 Ohms with real 50 Ohm source Z and 1 nS risetime. For that I made an output driver using 15 V supply and high speed op amps, two in parallel. But that would be an overkill for what you are doing. See some comments inserted below. At 04:17 PM 4/7/2006, Hal Murray wrote: You might find good chips intended for use as clock buffers. They probably won't come in DIPs so wiring them up as a hack will be a pain. They usually come with good data sheets and app-notes. There are also many high speed line drivers which are multiple to a package and typically have good section-to-section matching. I'm pretty sure I've seen an app-note saying it was OK to parallel drivers in the same package. I wonder what the technology was. This may have been for one particular IC. Do not directly connect multiple outputs, even in same package. Phase difference in the risetime of sections can cause very high instantaneous currents between sections. Even though the durration is short, and therefore no heating problems, the high current causes glitches within the IC. This can mess up the timing of the rise, which is important for a clocking application. I put a nominal R in each output path, 22 Ohms in my case, to limit current from section to section. Then at the junction of all these output resistors, I put a single R to the output connector to set the desired output Z. Tom Buehl ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Fw: HP 105 powersupply problems
Hello everyone: Another method is to apply power for only 2-3 seconds; Much safer for switching supplies than low voltage. This charges up the capacitors; If capacitors are leaking, there is no source of current to cause overheating or other failure modes. The charge which remains on caps allows electrolytic barrier to re-form. Repeat this a dozen times over the course of a day. Tom Buehl At 03:23 AM 4/4/2006, Robert Atkinson wrote: Hi all, Using a Variac over a long period of time is great with conventional (Transformer-rectifier-capacitor) linear PSU's, but be careful with more modern equipment with switchmode PSU's. They can draw excessive current during undervoltage conditions. Still use your Variac, but ramp it up a little quicker, maybe 30s to a minute. Watch out for auto supply voltage (115/230) switch designs too, it's best not to cross the switching boundary too slowly as they may not switch back from voltage doubling to full-wave rectification resulting in very excessive internal voltages. If you don't have a Variac, try a low wattage (40W) light bulb in series with the supply to limit the current. Robert G8RPI. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Poul-Henning Kamp Sent: 04 April 2006 06:28 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Fw: HP 105 powersupply problems In message [EMAIL PROTECTED], Richard and M arcia Putz writes: I had similar problems with my HP105, not bad transistors, check out the filter capacitors. Electrolytics in any equipment past 15-20 years of age could be suspect. I'd look there first. In general when powering up equipment that has been turned of for years: Use a variac and ram the voltage up slowly over a couple of days. Electrolytics can loose their polarisation over time and if exposed to full voltage they are likely to splatter all over the place, but if you give them a slow start they will most often recover their polarisation and work fine. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | 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 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts Any opinions expressed in this email are those of the individual and not necessarily Genetix Ltd (Genetix) or any company associated with it. This email and any files transmitted with it are confidential and solely for the use of the intended recipient. If you are not the intended recipient or the person responsible for delivering to the intended recipient, be advised that you have received this email in error and that any use is strictly prohibited. If you have received this email in error please notify Genetix by telephone on +44 (0)1425 624600. The unauthorised use, disclosure, copying or alteration of this message is strictly forbidden. This mail and any attachments have been scanned for viruses prior to leaving the Genetix network. Genetix will not be liable for direct, special, indirect or consequential damages as a result of any virus being passed on, or arising from alteration of the contents of this message by a third party. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] manuals
Can anyone provide info on a source for manuals for Tektronix 1240 logic analyzer and HP 8565A spectrum analyzer? Also information on probes and output connections for the Tek 1240 would be appreciated. Thanks, Tom Buehl ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] manuals
Chuck: Thanks for warning. Do I have to have unit powered up when changing battery? Tom At 02:05 PM 3/10/2006, you wrote: Replace your 1240's battery! It is a disaster waiting for a time to happen. Use a new CR2477 with welded on tabs. The same pacemaker battery is also in the 1240/41's RAM cartridges. -Chuck Harris buehl wrote: Can anyone provide info on a source for manuals for Tektronix 1240 logic analyzer and HP 8565A spectrum analyzer? Also information on probes and output connections for the Tek 1240 would be appreciated. Thanks, Tom Buehl ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] manuals
Chuck: User data noted; So power off while changing is OK. Thanks, Tom At 03:30 PM 3/10/2006, you wrote: buehl wrote: Chuck: Thanks for warning. Do I have to have unit powered up when changing battery? Oops! I read changing to be charging. The only data the cells protect is user setups. There is no calibration data at risk. -Chuck ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Arnold's counter design
Arnold: How are you progressing on your counter design? Would be best to take this discussion off-list. Advise your email address; Tom[EMAIL PROTECTED] At 02:09 PM 10/16/2005, you wrote: Hi Tom, I am very much interested on your works and results, it sounds to be a interesting way, nice project. Unfortunately I do understand nothing of these new devices. I would like to keep in touch with you, thank you. ON 16 OCT TOM BUEHL WROTE: Arnold: Some more info regarding use of Xilinx FPGA for counting. I recently completed a design using Xilinx Spartan II FPGA. This FPGA is only specified for maximum 200 MHz internal clock. My skills in this area are very limited, and this is my first for FPGA design. When finished, it counted reliably to above 210 MHz. Input pulses about 2 nS wide. So the performance of the Xilinx parts are excellent. This was a pre-set counter: Enter desired count number into registers/ memory, and the counter would output pulse when this count finished. Counting could be triggered or could automatically begin again. Therefore the OUTPUT could be every 10 pulses, up to every 999,999,999 pulses, with resolution of 1 pulse. Although this was not interfaced with time reference, circuit could be modified to compare with a reference. I have a plan to do the next one with higher speed Xilinx, and also know how I will be able to get counting at twice the internal clock rate of the FPGA. This would make the FPGA with minor additional circuitry able to count at greater than 500 MHz. Just as other time_nuts cautioned, the problem is handling the input signals at this frequency. Even at the 200 MHz rate, the very high transition time of the input pulses required that the circuit be clean at 1 GHz. You really need to design the input circuit first, so that the input signal is properly conditioned to provide clean data pulses to the FPGA. This was my biggest mistake on the first design. The FPGA counted fine if driven directly from a generator, but amplifying the input signals to adjust gain and trigger threshold was a VERY big design task. As you preceed, I would be glad to give you my comments on your work. Regards, Tom Buehl [EMAIL PROTECTED] ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Micro Phase Stepper: Thank you!
Quoting Ulrich Bangert [EMAIL PROTECTED]: Hi Folks, thank you very much for your kind explanation and hints regarding micro I imagine very well how a dac driven constant current source sourcing or sinking a small capacitor in conjunction with a comparator may give a variable slope linear ramp allowing very fine delay steps. The DAC sets the reference for the comparitor, while the 'ramp' remains constant. Thus you can trigger at any point on the ramp, the resolution of which is the accuracy limit of the comparitor and the DAC. The max to min time range is determined by the slope of the ramp. Time from starting the ramp (application of current source) to the detection point (and related comparitor propagation delays). Using two comparitors/ two DACs allows a START and STOP arangement to define a time interval; Either two pulses, or with logic a variable width pulse (limited by the rise/ fall time of the logic). Regards, Tom Buehl However, even with a arrangement like that, i would expect the device to have a minimal delay of say the propagation delay of the comparator plus one or two gates in a current semiconductor technology, so '0' to x.xxx ns is perhaps a bit too optimistic??? Or have those high tech guys some 'faster than light' technology available for compensation of propagation delays??? If ready to go integrated circuitry is available like the MAXIM parts, this is pretty much like a invitation to use them but i will remember Tom Buehl's suggestion and check their precision first before i use them in a real project. I have not checked Tom Clarke's links due to my slow private ISDN line (I live in a region of Germany where we have more cows than humans per square kilometer. We will be lucky to get DSL at the end of the year). Will check that the next day at my working place where we have a DSL-3000 line. Thank you all for your help, this group is definitely the 'high signal-to-noise ratio place' that John is asking for! Ulrich Bangert, DF6JB ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
