Re: [time-nuts] Performance of 74LVC series ICs
One thing that is hidden in AC and later CMOS is very tightly controlled edge-rate to combat ground bounce. The original AC components were so fast, the ground bounce could be measured in volts and they had to be quickly redesigned. For the D-FF function, you might consider using one section of the dual 74LVC74. With the inputs of the unused section connected to ground or Vdd, it will draw no power. David N1HAC On 6/8/15 8:30 PM, Dan Watson wrote: I have something of a follow up question. How good is the isolation inside these devices (74LVC, SOT-23 package) between gates? Let's say I have a 20MHz TCXO. I want to square up the output signal and divide by two. Easy, just a buffer or inverter and a flip flop. But looking at the pinout of the 74LVC1G175 (D flip flop) it doesn't have a Q not output. So now I need a second inverter to make it toggle. The 74LVC2G14 includes two schmitt inverters in the package, but will isolation inside the device be good enough to use it for two separate functions at 20 and 10 MHz? Just from a layout perspective using three devices instead of two would be easier. However the thing will be battery powered, so I'd like to save the power if possible. Thanks Dan On Mon, Jun 1, 2015 at 6:13 PM, Andy ai.egrps...@gmail.com wrote: The gates on that page http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/trangate.html use bipolar transistors. The 74LVC parts are CMOS. There are various effects caused by that difference. And those examples have vastly inferior control over input switching levels, compared to just about any well made digital IC from the last half century. (Funny to think that it has been half of a century!) 2N type transistors might have switching delays upwards of 100 ns (depending on load), whereas the LVC parts switch in the 1-5 ns range. On the other hand: A well designed discrete circuit can beat a general purpose integrated circuit in almost all performance measures. Some performance metrics would be hard to beat with even a well designed discrete circuit. On-die capacitance and inductance tends to be much smaller than any discrete circuit can achieve. Andy ___ 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] Performance of 74LVC series ICs
watsondani...@gmail.com said: Let's say I have a 20MHz TCXO. I want to square up the output signal and divide by two. Easy, just a buffer or inverter and a flip flop. But looking at the pinout of the 74LVC1G175 (D flip flop) it doesn't have a Q not output. So now I need a second inverter to make it toggle. The 74LVC2G14 includes two schmitt inverters in the package, but will isolation inside the device be good enough to use it for two separate functions at 20 and 10 MHz? The simple answer is to use the 74LVC1G74 which has the inverted output. The complicated answer is more complicated. What are you using the inverter for? Clock or data? If both halves are used for data and there is plenty of setup/hold time, then the timing through the chip doesn't matter. If you are using it for a clock, then things get interesting. Is there a fixed phase between the 2 signals? If they never change at the same time, it probably doesn't matter. (How close counts as same might get interesting.) If they do, how nutty are you feeling? If it mattered, I'd probably do something else. The simplest something-else is to use 2 packages. -- These are my opinions. I hate spam. ___ 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] Thunderbolt Power Supply Suggestions
csteinm...@yandex.com said: Power One HTAA-16W-A is one popular linear supply for use with the TBolt. I just poked around a bit. I think the current version is the HTAA-16W-AG. I assume the extra G is for green. -- These are my opinions. I hate spam. ___ 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] Thunderbolt power connector crimper
If you only have a handful of pins to crimp, I would not buy the crimper tool. It is possible but time consuming to use other hand tools or solder. I've done a few that way, and so it takes 5 minutes to make one connection, if you are only ever going to do four. I do own watch type crimpers for the kinds of terminals I use frequently On Mon, Jun 8, 2015 at 5:58 AM, Mike Feher mfe...@eozinc.com wrote: I forget the size of the pins on the Thunderbolt, but, I bought a crimper tool for Molex pins a while ago for a rather good price and really like it. This will crimp multiple gauge Molex pins and as I mentioned is very reasonably priced.. Shipping to Oz is another matter :).. 73 - Mike http://www.powerwerx.com/search.asp?q=ct-oem Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Matt Robert Sent: Monday, June 08, 2015 6:29 AM To: time-nuts@febo.com Subject: [time-nuts] Thunderbolt power connector crimper Hi Guys, I am currently in the process of completing my Thunderbolt project and I need to find a suitable crimper to attach wires to the pins that go inside the power connector. The only reference I can find is on this page here ( http://www.prc68.com/I/ThunderBolt.shtml) that talks about the official Molex tool which is scarily expensive, and the page also mentioned a Radioshack tool that I can't find any further details on. Can someone please point me in the right direction of a suitable crimper for the Molex 538-16-02-0103 pins. Cheers, Matt VK2LK ___ 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] TymServe 2100 and the 1995 GPS issue
Gerhard Wittreich kirjoitti: Once locked I did notice something interesting but maybe not important. The control voltage to the oscillator (timing util tfp 0) went from a very consistent 0xba6f to a 0xbb02. That's about 0.2% of scale. I'll watch it over the next few days to see where it settles in. Sounds like oscillator aging to me, sometimes they do larger jumps, stay there for a while and then again... Also it would not be suprising that this would happen just after the power was off and oven was cooled down for a moment. Also, brand new oscillators seem to age more rapidly at start and then settles down when older but the effects of aging will never stop completely. But they seem to get better and better when aging. I'm also waiting my MTI OCXO to arrive... -- 73s! Esa OH4KJU ___ 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] Trimble 65256 OCXO info?
Bob, I've used one for a simple 10 Mhz ref. They are 12 V, and indeed the VFC is +2.5V If you hold the OCXO upside down, the 2 pins at the top are GND and +12V Bottom 3 Pins - 10 Mhz, unknown and VFC Frits W1FVB On 09/06/2015, Bob Stewart b...@evoria.net wrote: Does anyone have any information about the Trimble 65256 OCXO? I bought one recently and hooked it up to 12V per the vendor. (Yeah, I know.) Although it worked, it set off such a stench: the usual electronics burning up, give you a sore throat smell. So, I got a replacement and same thing. For fun, I hooked it up to +5V. It seems to work, it drives the counter, but I haven't measured the output waveform yet. So, does anyone know whether these are +12V devices, +5V, or something else? The VRef output was somewhere around +2.5V, IIRC. Bob - AE6RV ___ 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. -- vbradio.wordpress.com ___ 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] Performance of 74LVC series ICs
Hi Dan, 74LVC1G80. See: http://www.ti.com/lit/ds/symlink/sn74lvc1g80.pdf Might be worth looking at. Dan On 6/9/2015 4:24 AM, time-nuts-requ...@febo.com wrote: Let's say I have a 20MHz TCXO. I want to square up the output signal and divide by two. Easy, just a buffer or inverter and a flip flop. But looking at the pinout of the 74LVC1G175 (D flip flop) it doesn't have a Q not output. So now I need a second inverter to make it toggle. The 74LVC2G14 includes two schmitt inverters in the package, but will isolation inside the device be good enough to use it for two separate functions at 20 and 10 MHz? ___ 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] Electronically Disciplined Mechanical
Hi Tom, Thanks a lot for your feedback and for having been an inspiration for this project. With a temperature-stabilized setup, it is now concievable to run the system at a constant impulse duration. This would not have been possible without temperature control, as the pendulum arm length varied too much to maintain an oscillation using a constant impulse width. I tried this overnight at a couple of occasions with an aluminium arm, only to find the pendulum dead in the morning... :-o So in order to achieve this, I will add a serial command to keep the last impulse duration. That command would be sent once the system is fully stabilized. Thanks, Bert, VE2ZAZ Message: 8 Date: Mon, 8 Jun 2015 14:46:50 -0700 From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Electronically Disciplined Mechanical Pendulum Message-ID: ED4D31631FC440A19A71631386F46143@pc52 Content-Type: text/plain; charset=utf-8 Hi Bert, Thanks for posting that project. What a wonderful combination of electronic and mechanical timing, of design and measurement, of hardware and software, of PICs and Python. One side experiment that would be interesting is to collect a couple of days of data using a fixed drive and then compare that with the same number of days using your adaptive FLL drive. The resulting phase or rate or ADEV plots would be amazing. /tvb - Original Message - From: Bert, VE2ZAZ ve2...@yahoo.ca To: time-nuts@febo.com Sent: Monday, June 08, 2015 10:11 AM Subject: [time-nuts] Electronically Disciplined Mechanical Pendulum Greetings, I just want to let those who are curious about disciplining a mechanical pendulum that I have pretty much wrapped up playing with a 1m-long pendulum, which I control with PIC micro firmware and try to mainain at a constant temperature. Accuracy for 20-second averaging is typically better than 1 ppm. I have documented my work here: On my website ( http://ve2zaz.net/Pendulum_Ctl/Pendulum_Ctl.htm ), On Youtube ( https://www.youtube.com/watch?v=7NdGX4A8W88 ) Thanks, Bert, VE2ZAZ ___ 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] Using CPLD/FPGA or similar for frequency
Hi, This thread really makes me want to do an FPGA timing project. I have a Papilio One on hand, which uses the Spartan 3E. But what to do with it? It has to be something much more interesting than what a PicDiv or simple logic can do to make it worth my time. Hmm... How about a 1pS resolution TIC? :) Or a 12 digit frequency counter? :) :) It's not a proper time-nut project unless there's a nutty element... Alan ___ 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] TymServe 2100 and the 1995 GPS issue
Very good point...It is a new oscillator that has been sitting in a box for 10-15 years. I'll give it a few weeks to settle in. The other very interesting thing I noticed was the variability in the oscillator control voltage before and after installing the new Heol Design GPS. The moving average of the standard deviation of the oscillator control voltage before and after installing the Heol Design gps was striking. The variability of the control voltage for the Heal Design is nearly 1/3 of that for the original Trimble gps. That suggests that the pps signal from the new gps module has 1/3 the variability vs the original gps module. I did consider that this could be due to the new oscillator aging but when I do a linear regression on the standard error of the control voltage before replacing the gps module the p-value for the slope of the line is about 0.5 suggesting that the null hypothesis, that the slope is actually zero, cannot be rejected. Therefore, one would need to conclude that there is no change if control voltage variability vs time prior to the installation of the new gps module and, consequently, there was no change in the stability of the new oscillator (since everything else remained unchanged). Unfortunately, I do not have sufficient run time on the new gps module to reach any meaningful conclusion of variability vs time. If anything it still appears to be dropping at this point. I can further update once I get additional run time. I also noted a very marked improvement in the satellite signal strength reported by the TS-2100. While I don't have any statistically sound data my observation is that the signal strengths are significantly higher and there are always more viable satellites in view. In the past I would never see more that 6-8 with 4-6 having sufficient signal strength. Now I routinely see 10 with 6 - 8 having sufficient signals strength. [image: Inline image 1] Note: The straight lines represent the mean value and are not linear regression although the linear regression and the mean line are very nearly the same for the original GPS data. I suspect the same will happen once I get some run time with the new GPS. Both imply that there is little time dependence, in the short term, on control voltage variability. Gerhard R Wittreich, P.E. On Tue, Jun 9, 2015 at 8:59 AM, Esa Heikkinen tn1...@nic.fi wrote: Gerhard Wittreich kirjoitti: Once locked I did notice something interesting but maybe not important. The control voltage to the oscillator (timing util tfp 0) went from a very consistent 0xba6f to a 0xbb02. That's about 0.2% of scale. I'll watch it over the next few days to see where it settles in. Sounds like oscillator aging to me, sometimes they do larger jumps, stay there for a while and then again... Also it would not be suprising that this would happen just after the power was off and oven was cooled down for a moment. Also, brand new oscillators seem to age more rapidly at start and then settles down when older but the effects of aging will never stop completely. But they seem to get better and better when aging. I'm also waiting my MTI OCXO to arrive... -- 73s! Esa OH4KJU ___ 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] More Wenzel Oscillators
I have two more Wenzel 100MHz Oscillators for sale. These do not have a voltage tuning port. The tuning is by a mechanical variable capacitor. They can also be tuned by varying the supply voltage. The data sheet is available. http://www.febo.com/pages/oscillators/100_MHz_Data_Sheets/wenzel_500-07078.pdf The phase noise is lower than the previous 100MHz oscillators. $50.00 for each oscillator. $10 for each shipping package. I am willing to ship both oscillators in one package. Ivan Cousins ___ 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] TymServe 2100 and the 1995 GPS issue
That sort of control voltage shift is not unusual if you take an OCXO that had been on for an extended period (for some of us... years or decades!), let it cool, then start it up again. Good google search terms are OCXO retrace and OCXO hysteresis. Tim N3QE On Mon, Jun 8, 2015 at 4:45 PM, Gerhard Wittreich gerh...@wittreich.org wrote: I just received the Heol Design N024 Trimble ACE III clone to resolve the week rollover problem we have been experiencing in the TS-2100's with the original Trimble ACE III gps units. Installation was very straight forward taking about 5 minutes. On a cold restart I had Tracking within 40 seconds with the correct date and time (Leap second issue also resolved) and Locked with my new OCXO in ~20 minutes. Once locked I did notice something interesting but maybe not important. The control voltage to the oscillator (timing util tfp 0) went from a very consistent 0xba6f to a 0xbb02. That's about 0.2% of scale. I'll watch it over the next few days to see where it settles in. Gerhard R Wittreich, P.E. On Thu, Jun 4, 2015 at 11:38 AM, Sean Gallagher s...@wetstonetech.com wrote: Hey everyone, Just wanted to send this out. It is The documentation that Heol has sent me regarding the GPS replacement boards in the 2100. According to them so far they were able to correct the issues with some fancy firmware on their N024 board. He also told me they are going to support firmware updates up to 2035 in case more issues arise. He is sending me one of these new units and should arrive within the next 2 weeks and I'll let you know if it works in my 2100's and my Datum/Symmetricom BC635pci cards. Respectfully, Sean Gallagher Malware Analyst 571-340-3475 ___ 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] HP5370 Error 04
Hello John, thanks for that information. Unfortunately, my fan is working. Opening the lid and putting an extra blower to cool the VCO helps to extend the time until he error occurs... Regards, Matthias Hello Matthias - I had this problem on my 5370B - it turned out that the fan wasn't running, which resulted in overheating. I hope this helps. Regards, John K1AE -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Matthias Jelen Sent: Monday, June 08, 2015 9:28 AM To: time-nuts@febo.com; dk...@gmx.de Subject: [time-nuts] HP5370 Error 04 Hello! I´ve got a question to the 5370 experts on the list. I just received my new (old...) HP5370a. It performed fine for abt. one hour, then it started to display error 04 which means PLL out of lock. A look in the service manual revealed that there are several reasons for this. I checked the VCO voltage on both interpolator cards, and indeed, one of them is out of the specified -6V..-3V, it runs to the rail (-12V). Even if the error is not there, the voltage is at abt. -7 V, so I guess it´s just on the edge. The other card is fine. Normally, I´d try the alignment procedure, but I´m missing the exotic HP pulse generator used for the alignment and I have no clue how I could easily substitute this one. Did anyone encounter this problem before? Is there a cure for this problem known to the experts? Any hints are highly appreciated... Thanks a lot, Matthias, DK4YJ ___ 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. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] Electronically Disciplined Mechanical Pendulum
On 06/08/2015 01:11 PM, Bert, VE2ZAZ wrote: I just want to let those who are curious about disciplining a mechanical pendulum Hello Bert, It is good seeing this in motion. I have had this project in mind since I read the article in Scientific American, A Venerable Clock Is Made Highly Accurate By Equipping It with Quarts-Crystal Works., September 1974. Wall clock of Seth Thomas manufacture, modified by Laurance M. Leeds. Recently I bought a working pendulum clock with the notion of doing the same, but with modern electronics and a closed loop feedback method, LEDs and sensors, rather than open loop as in the article. It is such a beautiful clock though, and it ticks so nicely, I wonder if I should mess with it even if all my electronics is invisible. The SA article really is titled with Quarts. .. my first post here, a test as well. Ian, G4ICV, AB2GR -- ___ 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] Performance of 74LVC series ICs
Hi The isolation in the package is likely better than the (practical) layout you will do to mate up with them. In fact, the single gate stuff probably does a better job of isolation than the multi gate stuff, simply because you can spread it out on the board. In the case of dividing by two, there are single gate flip-flops that are Q bar output rather than Q. That eliminates the second single gate package in this design. Yes, there are far to many different numbering systems. Finding this or that can be a massive pain. == If power is an issue, the real trick is to find a family that is happy running on a low(er) supply voltage. Some of this stuff will toggle at 20 MHz with very low supply. Often the inputs are “high voltage tolerant” even with those low supplies. Bob On Jun 8, 2015, at 8:30 PM, Dan Watson watsondani...@gmail.com wrote: I have something of a follow up question. How good is the isolation inside these devices (74LVC, SOT-23 package) between gates? Let's say I have a 20MHz TCXO. I want to square up the output signal and divide by two. Easy, just a buffer or inverter and a flip flop. But looking at the pinout of the 74LVC1G175 (D flip flop) it doesn't have a Q not output. So now I need a second inverter to make it toggle. The 74LVC2G14 includes two schmitt inverters in the package, but will isolation inside the device be good enough to use it for two separate functions at 20 and 10 MHz? Just from a layout perspective using three devices instead of two would be easier. However the thing will be battery powered, so I'd like to save the power if possible. Thanks Dan On Mon, Jun 1, 2015 at 6:13 PM, Andy ai.egrps...@gmail.com wrote: The gates on that page http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/trangate.html use bipolar transistors. The 74LVC parts are CMOS. There are various effects caused by that difference. And those examples have vastly inferior control over input switching levels, compared to just about any well made digital IC from the last half century. (Funny to think that it has been half of a century!) 2N type transistors might have switching delays upwards of 100 ns (depending on load), whereas the LVC parts switch in the 1-5 ns range. On the other hand: A well designed discrete circuit can beat a general purpose integrated circuit in almost all performance measures. Some performance metrics would be hard to beat with even a well designed discrete circuit. On-die capacitance and inductance tends to be much smaller than any discrete circuit can achieve. Andy ___ 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] Thunderbolt Power Supply Suggestions
Meanwell is good - have used several and have had no problems with them. 73, Bill, WA2DVU Cape May -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of skipp Isaham via time-nuts Sent: Monday, June 08, 2015 6:30 PM To: time-nuts@febo.com Subject: [time-nuts] Thunderbolt Power Supply Suggestions Hello fellow Time Nuts... I've obtained a Trimble Thunderbolt (from Ebay) and I'm in the process of searching out a practical power supply option. I've got the proper plug and pins already on order from Mouser. I've identified the Meanwell T-30B as a decent power supply. I like Meanwell power supply products quite a bit. Anyone have pro or con comments or alternative supply suggestions, else I go with the t-30b unless something else crosses my radar screen. Thank you in advance for your replies regards, skipp skipp025 at ya who period com ___ 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. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] Performance of 74LVC series ICs
Hi The question is always “good isolation compared to what?”. If you are expecting 180 db of isolation on a SOT-23 package at 10’s of MHz, it’s not going to happen. It’s also not going to happen with a practical pc board layout even without the SOT-23 involved. If something around 120 db is “good isolation”, then yes you can do that with a pair of the SC-70 parts and a good layout. In this case the test was at 10 MHz. Bob On Jun 9, 2015, at 12:26 AM, Andy ai.egrps...@gmail.com wrote: I have something of a follow up question. How good is the isolation inside these devices (74LVC, SOT-23 package) between gates? Maybe it's just me ... but I wouldn't trust the isolation to be good. Apart from on-die coupling, they share the same power/ground leads, however short they are. So just getting power and ground from the board onto the die, they would be corrupted by what happens in the other gate and its load (L*di/dt). Andy ___ 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] Electronically Disciplined Mechanical
Hi Bert at the Neu Tecknicumbuchs, /Buchs/, Switzerland somebody made a diplom work a quite-few years ego very similar clock, the pendulum was synchronized to the 75kHz accurate time transmitter, you may could find out more about it at the Neu Tecknicumbuchs, /Buchs/, Switzerland 73 KJ6UHN Alex On 6/9/2015 7:26 AM, Bert, VE2ZAZ wrote: Hi Tom, Thanks a lot for your feedback and for having been an inspiration for this project. With a temperature-stabilized setup, it is now concievable to run the system at a constant impulse duration. This would not have been possible without temperature control, as the pendulum arm length varied too much to maintain an oscillation using a constant impulse width. I tried this overnight at a couple of occasions with an aluminium arm, only to find the pendulum dead in the morning... :-o So in order to achieve this, I will add a serial command to keep the last impulse duration. That command would be sent once the system is fully stabilized. Thanks, Bert, VE2ZAZ Message: 8 Date: Mon, 8 Jun 2015 14:46:50 -0700 From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Electronically Disciplined Mechanical Pendulum Message-ID: ED4D31631FC440A19A71631386F46143@pc52 Content-Type: text/plain;charset=utf-8 Hi Bert, Thanks for posting that project. What a wonderful combination of electronic and mechanical timing, of design and measurement, of hardware and software, of PICs and Python. One side experiment that would be interesting is to collect a couple of days of data using a fixed drive and then compare that with the same number of days using your adaptive FLL drive. The resulting phase or rate or ADEV plots would be amazing. /tvb - Original Message - From: Bert, VE2ZAZ ve2...@yahoo.ca To: time-nuts@febo.com Sent: Monday, June 08, 2015 10:11 AM Subject: [time-nuts] Electronically Disciplined Mechanical Pendulum Greetings, I just want to let those who are curious about disciplining a mechanical pendulum that I have pretty much wrapped up playing with a 1m-long pendulum, which I control with PIC micro firmware and try to mainain at a constant temperature. Accuracy for 20-second averaging is typically better than 1 ppm. I have documented my work here: On my website ( http://ve2zaz.net/Pendulum_Ctl/Pendulum_Ctl.htm ), On Youtube ( https://www.youtube.com/watch?v=7NdGX4A8W88 ) Thanks, Bert, VE2ZAZ ___ 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.
