Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

Bob Pease recommended saving low gain transistors for operating margin tests. On Wed, 8 Jun 2016 18:35:58 +0200, you wrote: >... > >Another way to identify potential start-up problems is to cool down the >unpowered oscillator to the minimum operating temperature (or upper operating

Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

On Wed, 8 Jun 2016 08:20:45 -0700, you wrote: >Interesting, we just had a similar issue on a circuit here at work.. >someone slowly brought the supply voltage up on a bunch of DC/DC >converters, and some didn't start. This was in initial checkout of a new >board. > >Switch it on with a bang,

Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

On Wed, 25 May 2016 19:33:37 +0200, you wrote: > >> Le 25 mai 2016 à 16:59, David <davidwh...@gmail.com> a écrit : >> >> I was designed as a transmitter hunting antenna sacrificing size and >> gain for minimum side lobes. > >I’ve got to see your selfie.

Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

NAND Flash is especially bad about this. Not only can the data being currently erased or programmed be corrupted but other data can be also. That is why NAND Flash drives are so prone to complete failure even if a log type of internal file system is used; it is one thing to protect against

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

National's discrete products databook includes rough descriptions of the various processes, die shots showing geometry, and lists which transistors are fabricated on which process. On Sun, 19 Jun 2016 22:25:28 +, you wrote: >Once upon a time I came across a document from National

Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

On Fri, 24 Jun 2016 20:01:24 +0100, you wrote: >... > >I definitely concur with the 'make it SMT as much as possible' plan - >pin-mount stuff is a pain. Also, QFN is far preferable to QFP, as >catalogue suppliers don't always manage to ship fine-pitch stuff >without bending legs in one direction

Re: [time-nuts] Q/noise of Earth as an oscillator

On Wed, 27 Jul 2016 00:08:47 +0200, you wrote: >Hoi Tom, > >On Tue, 26 Jul 2016 12:36:37 -0700 >"Tom Van Baak" wrote: > >> Among other things, the quality-factor, or Q is a measure of how slowly a >> free-running oscillator runs down. There are lots of examples of periodic

Re: [time-nuts] Precision DACs (was: NCOCXO anyone?)

The AD5791 specifications under various conditions are all roughly consistent; 20 bits at DC, 16 bits at 10 ksps based on SFDR, and 12 bits at 1 Msps for large code changes. Its intended application is DC where its 1 Msps update rate applies for code steps of 500 or smaller and settling time will

Re: [time-nuts] NCOCXO anyone?

On Fri, 22 Jul 2016 11:33:12 +0200, you wrote: >On Thu, 21 Jul 2016 22:22:14 -0500 >David <davidwh...@gmail.com> wrote: > >> Increased integration has only helped insofar as you can attempt >> designs which would have been prohibitive before. >> >>

Re: [time-nuts] The home time-lab

I have never seen one which did not use a class-D output with L-C filtering. Total efficiency is in the 84 to 92 percent range. These days they also include power factor correction on their line input so they can be used to apply power factor correction to any load. Refurbished ones are

Re: [time-nuts] Precision DACs (was: NCOCXO anyone?)

On Sat, 23 Jul 2016 20:36:28 +0200, you wrote: >On the other hand, a modern DACs like the AD5791 reaches full 20bit at 1Msps >(resp 1us settling time to 0.02% @10V step, or 1us to 1LSB @500 code step). >But using the AD5791 in a design isn't easy either. The dual voltage reference >that is

Re: [time-nuts] The home time-lab

Are there some reference designs you can point to where this is a problem? Because all of the application notes and references designs I have checked so far have no requirements for input wave shape other than peak and to a lessor extent RMS voltage. The input power factor degrades with inputs

Re: [time-nuts] The home time-lab

The reason they call it a modified sine wave is that it is a square wave with the same peak and RMS voltages as a sine wave. Since the RMS value of a (bipolar) square wave is equal to its peak value, it has to include parts at zero or a lower voltage. Some inverters use additional voltage steps

Re: [time-nuts] Q/noise of Earth as an oscillator

We have discussed quartz crystals which despite their high Q, may suffer from periodic "jumps" in frequency do to what I assume are imperfection that hardly affect Q. If they did affect Q, then that would have been a good way to grade them for this behavior. Temperature coefficient is also

Re: [time-nuts] The home time-lab

On Sun, 24 Jul 2016 14:45:02 -0700, you wrote: >Hi Bob: > >The Sola 500 VA transformer is specified to hole up the line voltage for 3 ms. > (but not a half cycle of the line >frequency). > >I've connected the Sola CVS transformer to the output of the APC RS1500 backup >UPS. (needed to replace

Re: [time-nuts] NCOCXO anyone?

On Thu, 21 Jul 2016 18:47:24 -0700, you wrote: >On 7/21/2016 4:56 PM, Nick Sayer via time-nuts wrote: > >> Oh my. That’s a bit more than I was originally considering… What I had in >> mind was adding a DAC front end to an OCXO so that you could tune the EFC >> with serial commands rather than

Re: [time-nuts] Q/noise of Earth as an oscillator

On Wed, 27 Jul 2016 15:15:48 -0400, you wrote: >On 7/27/2016 10:04 AM, time-nuts-requ...@febo.com wrote: > >> Exciting the Earth with a new frequency (and an adeguate amount of >> energy) sets a new rotational speed: you cannot retune a (for example) >> quartz crystal in the same way... > >Sure

Re: [time-nuts] Very Accurate Delta Time RF Pulse

I have an Optoelectronics 3000A and as far as I know, the only thing distinguishing this capability from any other frequency counter is discrimination on the digital side which filters unstable counts. In practice it operates like an FM receiver where the strongest signal captures the input. If

Re: [time-nuts] Effect of EFC noise on phase noise

This duplicates the problems encountered when trying to quantify low frequency noise from a voltage reference; it is difficult to make an low frequency high pass filter with lower noise than the lowest noise references and the capacitor is the problem. In Linear Technology Application Note 124,

Re: [time-nuts] Effect of EFC noise on phase noise

possible circuits and check them all out … the >answer is that big C / small R wins. Big R gets you into resistor noise issues >and stray pickup. > >Bob > >> On Aug 1, 2016, at 4:16 PM, David <davidwh...@gmail.com> wrote: >> >> This duplicates the problems enco

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

red footprint would be the way to go.  Where does >one find that? > > >On Tuesday, August 9, 2016 12:00 AM, David <davidwh...@gmail.com> wrote: > > > Richard mentioned the SMD to leaded adapters which work well. > >Another way which is more suitable for Manh

Re: [time-nuts] Effect of EFC noise on phase noise

On Wed, 3 Aug 2016 14:01:30 -0400, you wrote: >Rick wrote: > >... > >> Anyway, what I was led to believe is that >> certain JEDEC 1N___ part numbers, with suffixes >> indicating noise properties, from particular >> vendors had much lower than average noise. Thus >> if a run of the mill zener

Re: [time-nuts] Heathkit clock available

On Wed, 10 Aug 2016 16:55:39 -0400, you wrote: >On 8/10/2016 11:31 AM, Nick Sayer via time-nuts wrote: >> Frankly, I don’t know why they didn’t make it a GPS clock. That would truly >> be a worthy successor to the GC-1000. Well, I do suspect I know why… and >> it’s not flattering. :) > >As I

Re: [time-nuts] Shera revisted

On Fri, 12 Aug 2016 13:56:40 +0200, you wrote: >Hi everyone, > >On 2016-08-11 21:06:12, Attila Kinali wrote: >> Hoi Bert, > >> I'm asking, because if you go the way of using a CPLD anyways, you could >> throw in another $2 for an opamp to build a time-to-amplitude converter >> (à la PICTIC II)

Re: [time-nuts] Working with SMT parts.

In the past when I had access to magnifying lamps and stereo microscopes suitable for printed circuit board work, I preferred the former. The extra magnification of the stereo microscopes was not needed and the large magnifying lamp was easier on the eyes although admittedly I wore glasses even

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

On Mon, 18 Jul 2016 11:43:32 -0700, you wrote: >except that virtually every UART in use today has some sort of buffering >(whether a FIFO or double buffering) between the CPU interface and the >bits on the wire, which completely desynchronizes the bits on the wire >from the CPU interface. >

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

The aged 16550 has various timeouts so an interrupt is triggered with a partially full buffer even if it is below the interrupt threshold. For implementations which do not do that, I assume they intend for the UART to be polled regularly. On Mon, 18 Jul 2016 23:42:34 -0400, you wrote: >I can't

Re: [time-nuts] How does sawtooth compensation work?

On Mon, 18 Jul 2016 21:41:51 -0700, you wrote: >> Or use the sawtooth compensation value to control an external variable >> delay line circuit > >Hi Mark, > >Right, one example is https://datasheets.maximintegrated.com/en/ds/DS1020.pdf >or google for silicon delay line. Not sure they're in

Re: [time-nuts] How does sawtooth compensation work?

On Mon, 18 Jul 2016 22:01:01 -0700, you wrote: >> It would be interesting to look at the data to see if you can find the sort > >Hi Hal, > >There's lots of examples of sawtooth patterns at: >http://leapsecond.com/pages/MG1613S/ > >In particular there's this monster:

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

On Tue, 19 Jul 2016 06:16:16 -0700, you wrote: >On 7/18/16 9:44 PM, David wrote: >> The aged 16550 has various timeouts so an interrupt is triggered with >> a partially full buffer even if it is below the interrupt threshold. >> For implementations which do not do that,

Re: [time-nuts] GPS for Nixie Clock

degree. Trigger point *is* dependent on the light >level. >You will need to collect real time data to keep things consistent. > >Bob > >> On Jul 16, 2016, at 10:49 AM, David <davidwh...@gmail.com> wrote: >> >> Use AC coupling to each digit to measure the ignition

Re: [time-nuts] GPS for Nixie Clock

Use AC coupling to each digit to measure the ignition waveform and detect the breakdown point like with a tunnel diode trigger. Use a higher compliance voltage and greater negative resistance (constant current drive?) to lower breakdown jitter. On Sat, 16 Jul 2016 00:08:45 -0700, you wrote:

Re: [time-nuts] The home time-lab

On Thu, 7 Jul 2016 21:31:58 -0400, you wrote: >If you decide to go the UPS route, don’t bother with anything that does not >produce a sine wave >output. Modern power factor corrected stuff is a lot happier with sine waves >than with weird looking >semi-square wave stuff. Active power factor

Re: [time-nuts] The home time-lab

Some UPSes like my old Powerware 9120 monitor the AC line condition for various things and keep a log but I do not know if that would be sufficient for what you have in mind. On Fri, 8 Jul 2016 01:54:58 + (UTC), you wrote: >So, since I need to power the 5370 (preferably both) I'm looking at

Re: [time-nuts] The home time-lab

On Fri, 8 Jul 2016 11:23:39 -0400, you wrote: >David wrote: > >> This is the only deal I see at the moment but I do >> not know how suitable it would be and it is more >> than I paid although about twice as powerful: >> >> http://www.upsforless.com/apcsurta150

Re: [time-nuts] The home time-lab

I wonder how well a pair of high voltage transformers wired back to back with a 60 Hz series resonate LC circuit between them would work for removing power line glitches. They wouldn't do anything for voltage regulation unlike a constant voltage transformer though. Time to break out a couple of

Re: [time-nuts] The home time-lab

And I will add a high voltage power resistor to limit the Q. On Fri, 8 Jul 2016 22:12:53 -0400, you wrote: >Hi > >If you try this, be very careful with the voltage at the junction of the L and >the C. > >Bob > >> On Jul 8, 2016, at 9:52 PM, David <davidwh...@gma

Re: [time-nuts] Using the HP 58503a to correct your PC clock

On Thu, 4 Aug 2016 19:05:13 + (UTC), you wrote: >My granddaughter would love to know I have a Tardis program. (-;>  Lots of >things to try here, just to get a more accurate clock. No wonder there's a >time-nutz group! The Tardis log shows that accessing external NTP servers is a problem

Re: [time-nuts] Using the HP 58503a to correct your PC clock

The old Tardis program for Windows (Tardis2000 now) handles it correctly by altering the rate and only jamming the time if it is outside of a specified window but I do not think its GPS mode supports the 1 PPS signal. I am not sure if Tardis works with Windows 7 and above though; I forget to test

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

I actually tested various 74120 dual 4-input NAND drivers which produce the sync output on my B function generator to find ones which would provide the fastest and cleanest pulse. AS (advanced schottky) and FAST (fast advanced schottky TTL) were the best for me. Modern inexpensive discrete logic

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

n Monday, August 8, 2016 8:02 PM, David <davidwh...@gmail.com> wrote: > > I actually tested various 74120 dual 4-input NAND drivers which >produce the sync output on my B function generator to find ones >which would provide the fastest and cleanest pulse.  AS (advanced >schottk

Re: [time-nuts] How does sawtooth compensation work?

The DC510 and DC5010 phase lock a 320 MHz varicap oscillator to the 1 MHz reference giving them a 3.125ns single shot timing resolution. The DC509, DC5009, DC510, and the DC 5010 are reciprocal counters. The universal timer/counters in the 2236, 2236A, 2247A, and 2252 oscilloscopes phase lock

Re: [time-nuts] Cable length calibration

The Tektronix 1502 uses a tunnel diode pulser to produce a 50 picosecond output step of about 200 millivolts. There is a misprint in the theory section of the service manual which says "400 V" instead of "400mV". On Thu, 30 Jun 2016 04:19:43 -0400, you wrote: >If the nominal velocity of

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

On Sat, 2 Jul 2016 19:00:24 +0200, you wrote: >On Fri, 1 Jul 2016 12:28:44 -0400 >Bob Camp wrote: > >> Real cascode circuits can be built with RF transistors. They also can be >> simulated. >> Simulating them with the “standard” models is a PIA. The issue is that the >>

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

>Why do people use general purpose transistors in these places, even >though RF transistors definitly improve switching behaviour? Commercial designs do use RF transistors but only old ones are documented. The Tektronix 7A11 uses 2 GHz PNPs and 1 GHz NPNs but its design is unusual since it can

Re: [time-nuts] Sub-ps delay line

I did something similar a couple years ago to make an adjustable 75 nanosecond pretrigger for my sampling oscilloscope so I will just pass along some things I learned. Power supply noise will create jitter in single ended logic because of lack of power supply rejection. Temperature will be a

Re: [time-nuts] Distribution amplifier (again!) - now mostly ok but has gain peaking

On Sat, 28 Jan 2017 13:58:27 +0200, you wrote: >... > >The picture gallery also shows a pulse distribution amp for 1PPS. It has an >LT1711 comparator feeding an 74AC14 buffer with length-matched traces to >74AC04's at the outputs. So far my length-matching didn't give zero >output-skew between

Re: [time-nuts] Line Frequency standard change - Possible ?

On Thu, 9 Feb 2017 19:06:51 -0500, you wrote: >One simplistic way to look at all this is that a switcher presents a “negative >resistance” load. If you drop voltage, current goes up. OCXO’s happen >to share this issue. Negative resistances are *not* what most power source >guys want in their

Re: [time-nuts] Line Frequency standard change - Possible ?

On Thu, 09 Feb 2017 23:39:24 +, you wrote: >It is harder than it sounds. > >Small solar inverters are the best, they an regulate down at milliseconds >notice, and many jurisdictions impose asymetric frequency bands on >them to exploit this. > >Big inverters, no matter what you put behind

Re: [time-nuts] Line Frequency standard change - Possible ?

On Thu, 9 Feb 2017 17:19:49 -0500, you wrote: >Isn't this "hard" lock to UTC creating a single point of failure? A >solar burst, an EMP, or >a software error could leave us all in the dark. After all, smart >inverters could be >programmed to act like big lumps of rotating iron and be

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

On Tue, 14 Feb 2017 10:31:30 -0500, you wrote: >On 14/02/2017 7:26 AM, Bob Camp wrote: > >> A direct port might be a +/- 100 ns sort of thing most of the time and a >> +/-10 us >> thing every so often under some OS’s. Most desktop operating systems are not >> designed to prioritize random pin

Re: [time-nuts] 10MHz to 25MHz

This document covers various methods but I agree with Rick about phase locking a separate crystal oscillator; harmonic frequency multiplication is more useful at higher frequencies where other methods are unavailable: http://www.qsl.net/va3iul/Frequency_Multipliers/Frequency_Multipliers.pdf An

Re: [time-nuts] wifi with time sync

Modern systems are very aggressive about DVFS (dynamic voltage and frequency scaling) so it would not surprise me at all. I have run across this problem on the timescale of one second even on 10 year old desktop hardware. On Sun, 15 Jan 2017 09:32:56 -0500, you wrote: >Hi > >I’d be surprised if

Re: [time-nuts] wifi with time sync

Sonos and I guess their competitors do this by dropping WiFi compatibility. They exist on their own network in the same ISM band so I wonder how well they coexist with WiFi. Online reports say poorly under crowded band conditions. On Sun, 15 Jan 2017 09:50:05 -0500, you wrote: >Hi > >The push

Re: [time-nuts] 10MHz to 25MHz

On Thu, 19 Jan 2017 10:48:57 -0800, you wrote: >On 1/19/2017 5:40 AM, David wrote: > >> oscillator. In some applications I would also be concerned about the >> phase of a narrow bandpass filter changing with temperature. > >The 5061 has tuned bandpass filter multip

Re: [time-nuts] 10MHz to 25MHz

On Wed, 18 Jan 2017 21:06:04 -0800, you wrote: >On 1/18/2017 6:34 PM, David wrote: > >> An alternative very simple design I might try is a variation of the >> active frequency multiplier where the 5th harmonic is filtered >> directly from the output of the digital divide

Re: [time-nuts] ADC sample voting algorithm?

I always try to calculate things like the standard deviation and peak-to-peak to get some idea if the measurement is valid. A DSO with infinite persistence or envelope mode is great for tracking this sort of thing down during development. Only toy DSOs will lack both. On Wed, 05 Oct 2016

Re: [time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

I would not use such a narrow pulse for any of those reasons except for power if that was an issue. I would and have however used narrow pulses simply because it allows for a lower volt*time product on a transformer. On Fri, 16 Sep 2016 21:03:12 -0400, you wrote: >Hi > >It is sort of an "

Re: [time-nuts] 53132A triggering

The new ones don't? That would be annoying. My old Racal-Dana 1992 remembers when in standby mode but not if it loses power. On Fri, 16 Sep 2016 15:21:50 -0400, you wrote: >Thanks, Bob. I just tried that and got solid results. One nice thing about >the 5370 vs this newer stuff is that the

Re: [time-nuts] HP-105B Battery Replacement?

I have a pair of Liebert GTX2-700RT online UPSes and they work well; I just replaced the batteries, lubricated the fans, and cleaned the dust out of them a couple weeks ago. They have that sort of standard 4 prong socket on the back for external batteries. But unlike my two Powerware Prestige

Re: [time-nuts] HP-105B Battery Replacement?

High end standby UPSes support external batteries but most or all online UPSes do. I have 3 different online UPS models and they all support external batteries of either 48 or 60 volts. On Thu, 15 Sep 2016 15:13:59 -0700, you wrote: >Since I have a 12V 100 A-H gelled electrolyte battery as a

Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.

Worn out aluminum electrolytic capacitors usually improve in performance lowering ripple and noise as they warm up. On Sun, 18 Sep 2016 12:27:38 +0100, you wrote: >Now that's interesting I just re-ran the measurement, and got a quite >different result which is attached. The spurs have GONE. >

Re: [time-nuts] Optical link connects atomic clocks over 1400 km of fibre

I could not find it in the links but Magnus mentions 50 Hz instead of 100 Hz. I would expect a 100 Hz noise signal if it was vibration coupled from magnetostriction in a transformer; magnetostrictive strain depends on the magnitude of the magnetic field strength and not the sign which is why

Re: [time-nuts] DIY VNA design [VNA-Nuts?]

On Mon, 22 Aug 2016 23:44:17 +0200, you wrote: >On Mon, 22 Aug 2016 14:20:59 -0400 >Bob Bownes wrote: > >> Just finished creating it at groups.io >> >> *https://groups.io/g/svna * >> and sign up. :) > >Is there any advantage of using groups.io compared

Re: [time-nuts] A new take on the all-hardware GPSDO concept

Is there a schematic showing what you attempted? I went back through the discussion thread and it was not real clear to me which design you implemented. On Mon, 26 Sep 2016 21:18:25 -0700, you wrote: >... > >The results aren’t very good. > >With a short TC loop filter, the PLL does lock up, but

Re: [time-nuts] Caroliine .. I need to move on

I was thinking message from Cave Johnson. On Sat, 1 Oct 2016 23:24:09 -0700, you wrote: >Hurricane I believe > >-=Bryan=- > >> From: jim77...@gmail.com >> >> Well I'm intrigued! >> >> On 2 October 2016 at 15:53, Ian Stirling wrote: >> >> > going to the emergency place

Re: [time-nuts] Temp/Humidity control systems?

Years ago I had to deal with this and the instruments and sensors we used matched well against dry and wet bulb measurements. I suspect consumer level stuff varies considerably in reliability and accuracy. The capacitive sensors are tricky to use because they require AC excitation to prevent

Re: [time-nuts] I love the smell of tantalum in the morning

I usually find that the pad itself has enough tin plating to melt and adhere the part's termination so I tack it down like that, solder the second termination, and then go back and solder the first termination. On Mon, 7 Nov 2016 02:34:51 +, you wrote: >The best way to hand solder small SMT

Re: [time-nuts] Man with too many clocks.

My simple solution to this was to divide the 1 PPS signal down so the jitter from the uncorrected GPS was a smaller part. Of course then each measurement takes proportionally longer. On Fri, 4 Nov 2016 11:35:59 -0400, you wrote: >I gave up on trying to use the GPS 1 PPS signal to calibrate the

Re: [time-nuts] Satellite TV messed up, how is GPS time

On Fri, 4 Nov 2016 18:23:16 -0400, you wrote: >I no longer have DISH but I did have it a year ago and the outage >happened every year like clockwork , they even sent me a notice that I >could expect a sun outage and I did.. I also experienced outages every >time a thunderhead at 30,+ feet

Re: [time-nuts] Thinking outside the box a super reference

On Fri, 04 Nov 2016 14:39:54 -0700, you wrote: >On Fri, Nov 4, 2016, at 02:27 PM, Poul-Henning Kamp wrote: >> >> In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, "Richard >> (Rick) Karlquist" w >> rites: >> >Also, one of the Rb isotopes is slightly radioactive. >> >35

Re: [time-nuts] Satellite TV messed up, how is GPS time

On Fri, 4 Nov 2016 18:43:03 -0400, you wrote: >... > > There HAVE been attempts to deliberately jam cable distribution >satellites... mostly the EIRPs used for distribution signal uplinks >make this a bit difficult, but it has been done. There are also some >countermeasures in place to

Re: [time-nuts] I love the smell of tantalum in the morning

On Sat, 5 Nov 2016 20:57:11 +0100, you wrote: >> Having not done SMT before, how should I do it with minimal risk to the very >> precious PCB. Or, what equipment should I use this as a good excuse to buy? > >Now, for these caps, you can use a normal soldering-iron without too >much trouble, but

Re: [time-nuts] 1PPS to 32.768 khz

On Tue, 18 Oct 2016 22:59:42 -0700, you wrote: >> 1. Does anyone know of a device that will take a 1PPS GPS timing signal and >> generate a 32.768 kHz sine wave output ? I have big digital clock that uses >> an 8 bit micro processor and an external 32.768 crystal. Obviously the >> external

Re: [time-nuts] measuring noise of power supplies (was: For those that insist on using switching power supplies)

On Tue, 18 Oct 2016 11:27:05 +0200, you wrote: >On Fri, 14 Oct 2016 22:25:55 -0500 >David <davidwh...@gmail.com> wrote: > >> I have done this and it works great; the breakpoint between the >> chopper amplifier and the low noise amplifier can be adjusted to >>

Re: [time-nuts] 1PPS to 32.768 khz

I was thinking 32.768kHz VCXO and phase detector to make a simple analog PLL. I found a datasheet for a suitable VCXO and assuming a total error of 20ppm, it would only need to be divided by 2 to prevent locking to the wrong frequency making an analog PLL pretty simple. Safer to divide by 4 or 16

Re: [time-nuts] measuring noise of power supplies (was: For those that insist on using switching power supplies)

I have done this and it works great; the breakpoint between the chopper amplifier and the low noise amplifier can be adjusted to combine the wideband noise from the low noise amplifier and the 1/f noise and drift of the chopper amplifier. Jim Williams wrote a couple of different application notes

Re: [time-nuts] measuring noise of power supplies

On Tue, 18 Oct 2016 14:52:15 +0200, you wrote: >Hoi David, > >On Tue, 18 Oct 2016 05:25:35 -0500 >David <davidwh...@gmail.com> wrote: > >... > >> thermal EMF becomes a large if not the largest contributor. > >Ah.. good to know. Thanks! >Any guess what th

Re: [time-nuts] Anybody want a Thunderbolt power supply?

On Fri, 21 Oct 2016 10:59:59 +0200, you wrote: >On Fri, 21 Oct 2016 00:20:43 -0400 >Scott Stobbe wrote: > >> The bad side of a 7912 is in long-term stability and tempCo, the sample I >> tested had at least a 150 ppm/degC tempCo, which is going to put a serious >>

Re: [time-nuts] How can I measure GPS Antenna quality?

When I was doing VHF and UHF direction finding antenna design, I would drive out to the highest readily accessible hilltop for testing. Once I came up with a low sidelobe design, I started picking up things like lamp posts, trees, and bushes in the parking lot, aircraft over LAX and John Wayne

Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

John, In what language is the GUI written? I might be able to help on that, or other parts of the software, if someone else hasn't yet volunteered. Dave, WA8YWQ On 2016-11-24 06:43, John Ackermann N8UR wrote: > Hi Anders -- > > Thanks, and thanks for the info on the 53230A. I have not

Re: [time-nuts] precision timing pulse

On Wed, 16 Nov 2016 11:14:59 -0800, you wrote: >albertson.ch...@gmail.com said: >> I'm wondering why everyone seems to be assuming a PIC is the right processor > >If you want cycle-accurate timing, one approach is to count cycles. If you >have an assembly level background, the PIC is as good as

Re: [time-nuts] Thermal impact on OCXO

I have only heard of and never observed the problem of manufacturers cutting the middle out of a gaussian distribution for tighter tolerance parts. Robert Pease of National Semiconductor had an even better story: I recollect the story of one of the pioneering transistor companies, back in the

Re: [time-nuts] our favorite topics

That is always the danger when using parts for characteristics not guaranteed in the specifications. Sometimes a process just becomes obsolete necessitation new parts to be fabricated on a new process. Or a process may have enough variation that some lots or parts meet unguaranteed

Re: [time-nuts] our favorite topics

You mentioned suitable transistor availablity being an increasing problem and I have run across that myself. Do you expect Qualcomm's aquisition of NXP to have an impact? NXP is currently the best source I have for fast complementary pairs or even just fast PNPs. On Sun, 30 Oct 2016 16:06:19

Re: [time-nuts] Opening an Isotemp OCXO

I do not think the designer was considering noise at all because tying the inputs together would not do anything useful. Emitter resistance is inversely proportional to emitter current (26/mA) but putting them in parallel lowers the current through each emitter so the total emitter resistance

Re: [time-nuts] What would be the proper equipment and procedure?

But I got my question answered anyway. :) On Sat, 29 Oct 2016 05:29:26 +, you wrote: >Yep, should have gone to volt-nuts. Recent changes Microsoft has been doing >to Outlook, etc have been causing all sorts of fun gltches. One being not >actually taking copy-pastes of addresses and/or

Re: [time-nuts] For those that insist on using switching power supplies

Even if they meet the CE or FCC requirements for unintentional radiators, they can still screw up the short wave bands and more; many are bad enough that I can see the noise they emit on an oscilloscope with a shorted probe. At least in the US, there are a *lot* of cheap products with switching

Re: [time-nuts] Totally unrelated, but..

On Thu, 8 Dec 2016 02:25:14 +0100, you wrote: >Am 08.12.2016 um 01:20 schrieb Scott Stobbe: >> Yes, the short hand I like to use is 4 nV*sqrt(R/1000). >> >> 2 nV/rthz off a bandgap is pretty darn impressive, that includes a delta >> vbe gained up ~10x. > >Methinks the advantage comes from

Re: [time-nuts] Totally unrelated, but..

I am pretty sure that I ran across this once as well with the 7800/LM340 series in the early 1980s with parts from a major manufacturer like Motorola, National, or Texas Instruments; the regulators ran hot and the output voltages were slightly low no matter what decoupling arrangements were made

Re: [time-nuts] Measuring sidereal/solar time? Re: A Leap Second is coming

To improve the accuracy, I would integrate several measurements. There is no reason a sampled measurement at only one time needs to be made. On Fri, 30 Dec 2016 09:18:17 -0800, you wrote: >Hi Anders: > >That's something I've thought about for decades using an optical system. A >few years ago

Re: [time-nuts] WWVB Simulator

Not all PC audio hardware includes such a low high frequency cutoff. http://www.clarisonus.com/Research%20Reports/RR001-SoundCardEval/RR001-PCsoundCards.html Based on the above review, the following cards which are still available have a response that extends significantly above 60kHz:

Re: [time-nuts] WWVB Simulator

I see generally how it should work but did not draw out a truth table. Why use the 74CB3T3253 instead of a low voltage 4052 variant? It think you could buffer just the two references and save two operational amplifiers and 2 or 4 capacitors. On Mon, 2 Jan 2017 21:18:12 + (UTC), you wrote:

Re: [time-nuts] Ublox M8N - have I a XO or TCXO ?

On Wed, 21 Dec 2016 19:29:00 +, you wrote: > Can anyone comment on the following data, and whether they think the > oscillator in "my" M8N is a XO or a TCXO ? > >Can you monitor the current draw from cold (ambient)? > >You may be able to identify the initial steady current drawn by

Re: [time-nuts] Problem with HP 83623A 20 GHz sweep generator stepping up/down 100 Hz when not wanted.

On Thu, 22 Dec 2016 12:39:27 +, you wrote: >But I find it a bit odd that HP would have a 1 Hz software option on this >instrument, if the instrument jumped up/down 100 Hz. > >Now I don't yet have the 1 Hz option programmed in, and it might well >change the behavior completely, but I'd still

Re: [time-nuts] Single ended or differential input to TDC chip

On Mon, 27 Mar 2017 18:05:13 +0200, you wrote: >... > >* Single-ended input in a chip might lead to shifting ground potential > on the chip and thus to measurment jitter. > >... This is a major problem I have run across before. Various single ended logic families have great noise immunity as

Re: [time-nuts] Antique precision timing device without electronics

I think Bob Pease of National Semiconductor fame mentioned looking for the earliest use of phase locked loops and finding a reference to a European clock maker who had a master pendulum clock with a mechanical coupling that phase locked newly built clocks when left connected overnight. On Thu, 16

Re: [time-nuts] TAPR TICC boxed (input protection)

Low current measurements take a lot of time on the automatic test equipment and time in this case is measured in seconds. The same applies to low frequency noise. For an example, take a look at the National (now TI) LMC6001 and LMC6081: https://goo.gl/LCY2vR Unlike National, TI does not care

Re: [time-nuts] TAPR TICC boxed (input protection)

On Wed, 5 Apr 2017 09:13:34 +1200 (NZST), you wrote: >A protection diode needs to also have a fast turn on with little or no >overshoot of the forward voltage. That would be ideal but forward turn on time is rarely specified and usually assumed to be fast and some fast diodes have appallingly

Re: [time-nuts] TAPR TICC boxed (input protection)

magnitude.  Considering that our electrometers had an input >impedance of 1E-12 to 10E-15, even a fingerprint made a huge difference.  The >carbon filled black paint was practically a short. >Maybe an overcoat with silicone or some other type of low leakage sealant, >then the black pai

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