Re: [time-nuts] Transformer inrush current and transformer simulation

Am 08.06.2016 um 02:31 schrieb Mike Monett: I was not interested in examining the frequency response, saturation effect or core losses. These are only important after the core goes into saturation. I was only interested in the result of switching at the peak or at the zero crossing. This is

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

The units were never intended for a slow ramp I assume it runs into a meta stable condition Neither on or off and then corruption Glad you're can repair them On Tuesday, June 7, 2016, Bob Camp wrote: > Hi > > Thanks for the heads up !! > > It almost sounds like they are doing some sort of “use f

[time-nuts] Divide by 3

I’m contemplating trying my GPS board with an FE-405B. That’s a different kettle of fish, but at the end of that, if I’m successful, one of the goals would be to be able to use it for the external reference of my 53220A. Unfortunately, 15 MHz isn’t one of the options - only 1, 5 and 10. So I di

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

On 6/8/16 6:19 AM, paul swed wrote: The units were never intended for a slow ramp I assume it runs into a meta stable condition Neither on or off and then corruption Glad you're can repair them On Tuesday, June 7, 2016, Bob Camp wrote: Interesting, we just had a similar issue on a circuit

Re: [time-nuts] Divide by 3

The URL you cited doesn't have the schematic in any obvious place. However, using both edges of the clock to supposedly result in 50% duty cycle output depends on having 50% duty cycle at the input. If you have differential logic like ECL, this can be realistic. Single ended logic, questionable

Re: [time-nuts] Divide by 3

> Le 8 juin 2016 à 15:55, Nick Sayer via time-nuts a écrit > : > > I’m contemplating trying my GPS board with an FE-405B. That’s a different > kettle of fish, but at the end of that, if I’m successful, one of the goals > would be to be able to use it for the external reference of my 53220A.

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

The same problem may appear on some poorly designed crystal oscillators. Some circuits depend on the spectral component of a fast power-on and will not start reliably if the supply voltage is ramped slowly - as can happen if the oscillator stage is fed by a voltage regulator with high value capac

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

Sounds similar to the issues you encounter with Atmel and some other EEPROM/Flash based MCUs when they're not held in reset until VCC becomes stable. http://atmel.force.com/support/articles/en_US/FAQ/Prevent-EEPROM-corruption Some more info: http://www.embedded.com/design/prototyping-and-develop

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, an

[time-nuts] O-451A/u 5 MHz oscillator: more photos

I added some more photos of the O-451A/U to a Dropbox folder . There are no obvious manufacturer marks beyond the Western Electric contractor cited on the Coast Guard nameplate on the front panel. Note that the large

Re: [time-nuts] Divide by 3

On Wed, 8 Jun 2016 18:35:43 +0200 Mike Cook wrote: > It is a no brainer to get a sine from a square wave, BUT , I seriously > doubt that the excellent ADEV can be maintained with all that flipping > and flopping going on. I even doubt that it could be kept in a pure sine > implementation. I wou

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 >temperature

Re: [time-nuts] Divide by 3

Nick wrote: I’m contemplating trying my GPS board with an FE-405B. That’s a different kettle of fish, but at the end of that, if I’m successful, one of the goals would be to be able to use it for the external reference of my 53220A. Unfortunately, 15 MHz isn’t one of the options - only 1, 5 a

[time-nuts] Divide by 3

The FE405B AD plot I recently posted used a simple (non 50% duty cycle) divide by 3 using a 74ls74 and 74ls02 (if I remember correctly). I used the HP board from the pair used in the 5065A or 5061A/B. The existing 74ls74 was piggy backed with the 74ls02 and connections made with tiny wire. The non

[time-nuts] FE-405B Reprogramming

Hi All, Nick's request for a divide-by-three circuit to get his FE-405B to output a 10MHz signal got me thinking - didn't want to threadjack. I had assumed that the FE-405B's DDS output and FE-5680 compatibility made it a good candidate for output frequency reprogramming. Has anyone deter

Re: [time-nuts] Divide by 3

utilizing rising and falling edges makes the circuit output signal duty cycle sensitive to the input signal's duty cycle, and therefore the harmonic content will vary with the input duty cycle variation. 73 KJ6UHN Alex On 6/8/2016 9:47 AM, Richard (Rick) Karlquist wrote: The URL you cited does

[time-nuts] GPS altitude somewhat wrong?

I have just installed a Thunderbolt here to get our time and frequency equipment all on the same page. As I was looking at the display on Lady Heather, I was noticing that the GPS altitude seems rather wrong. We are in Boulder CO, which is nominally 5430' and the antenna is about 20' off the gr

Re: [time-nuts] Divide by 3

att...@kinali.ch said: > Temperature, in an office or lab, does not change that much to cause large > differences. Maybe in your lab. I'd expect that will change as people get more sensitive to energy costs. Things like turning down/off the heat/cooling at night can lead to large swings. --

[time-nuts] Some FE405B data

Attila, All oscillators are not the same! Although I find the yield to be better for the FE405B than say the 10811 some are duds like the top trace in Toms data, some are very good like the bottom trace, and some are even better, my plot. I've been very impressed by the 405B performance as I hav

Re: [time-nuts] GPS altitude somewhat wrong?

A couple of things come to mind: 1) Is this a single measurement or an average over at least 24 hours? 2) Did you get your elevation via the receiver survey mode (recommended)? 3) How close is your "nominal" elevation measurement and what makes you think it is truth? 4) The vertical component of th

Re: [time-nuts] FE-405B Reprogramming

Hi The 405 appears to have some “bandpass” elements in it. You can not tune it over a wide range. Bob > On Jun 8, 2016, at 3:08 PM, Logan Cummings wrote: > > Hi All, > >Nick's request for a divide-by-three circuit to get his FE-405B to > output a 10MHz signal got me thinking - didn't wan

Re: [time-nuts] GPS altitude somewhat wrong?

Some of that is probably the difference between the geoid (what your surveyed maps report height relative to) and the WGS84 ellipsoid (what your GPS reports heights relative to). At Boulder that difference is only about 15 meters, though. Generally with VDOP < 2 and a reasonably modern receiver t

Re: [time-nuts] Divide by 3

In this case, the FE-405B outputs a sine wave, which is converted to square with a self-biased inverter. That’s fed into an NB3N551 clock buffer. Two of the outputs go off to the discipline system and the other two are user outputs, one of which would be fed into the circuit in question. On the

Re: [time-nuts] Divide by 3

There’s a link to the blog posting (not mine) that has the schematic on the OSHPark shared project. The schematic there isn’t *totally* obvious - the square boxes that are otherwise unlabeled are D flip-flops with D on the left and Q on the right. I’ve simulated the circuit at CircuitLab and go

Re: [time-nuts] GPS altitude somewhat wrong?

Yo David! On Wed, 8 Jun 2016 20:33:58 + "Van Horn, David" wrote: > I suppose 214' isn't that outrageous, but it does bring me to a > question: Looking at my GPS farm, fair but not great skyview. A Garmin 18x reports: Altitude Err:+/- 264 ft A u-blox 8: Altitude Err:+/-

Re: [time-nuts] GPS altitude somewhat wrong?

On Wed, June 8, 2016 3:33 pm, Van Horn, David wrote: > How accurate is the altitude number really? Probably not the question you really want to ask. Try "what does GPS mean by altitude? Altitude relative to what standard?" http://www.esri.com/news/arcuser/0703/geoid1of3.html -- Chris Caudle

Re: [time-nuts] GPS altitude somewhat wrong?

Per https://www.topoquest.com/map.php?lat=40.02486&lon=-105.24468&datum=nad27&zoom=2&map=auto&coord=d&mode=zoomin&size=m the address in your signature is close to the 5250 ft (geoidal) contour. Henry On Wed, Jun 8, 2016 at 3:18 PM, Henry Hallam wrote: > Some of that is probably the difference b

Re: [time-nuts] GPS altitude somewhat wrong?

I just checked Google Earth and the elevation of your office is 5260', only about 24' off of your GPS estimate if that is your location. Michael On Wed, Jun 8, 2016 at 1:33 PM, Van Horn, David < david.vanh...@backcountryaccess.com> wrote: > > I have just installed a Thunderbolt here to get our ti

Re: [time-nuts] GPS altitude somewhat wrong?

On Wed, Jun 8, 2016 at 4:33 PM, Van Horn, David < david.vanh...@backcountryaccess.com> wrote: > Backcountry Access, Inc. > 2820 Wilderness Pl, Unit H > Boulder, CO 80301 USA > Google Earth has the elevation of this address as 5272' which is a good deal closer to your reading... -- --Jim Harm

Re: [time-nuts] GPS altitude somewhat wrong?

Some of that is probably the difference between the geoid (what your surveyed maps report height relative to) and the WGS84 ellipsoid (what your GPS reports heights relative to). At Boulder that difference is only about 15 meters, though. Generally with VDOP < 2 and a reasonably modern receiv

Re: [time-nuts] FE-405B Reprogramming

Thanks Bob, I figured if it was that easy someone else would have already done it. Went looking for a schematic and found Tom's page describing the architecture at a high level and with ADEV plots providing evidence of said architecture. Good block diagram from an FEI presentation at the bo

Re: [time-nuts] Maser 0.7 nsec jumps solved

Hold your horses folks. There is more on this tale! To recap we put the SSR on the aircon (at zero crossing) and the jumps got very very worse. So we turned the aircon off again (winter here - so not really needed) and the jumps dropped, but didn't go away. :-( So we also have a heater in the ro

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

For what it’s worth, the GPS boards I’ve designed for the FEI devices use the TPS54[23]31 for the primary 15v supply (which also powers the 5v supply), and it has been configured with a hysteretic UVLO with a start threshold above 16 volts. Additionally, the slow-start is configured for somewher

Re: [time-nuts] Divide by 3

> On Jun 8, 2016, at 9:59 AM, Charles Steinmetz wrote: > > You can achieve substantially lower jitter (phase noise) with a regenerative > divider, which also allows you to divide by 3/2 for a 10MHz output. I've > built several like that, and they work extremely well. > > There are simpler di

Re: [time-nuts] GPS altitude somewhat wrong?

Hi Gary, >From one NW GPS farm to another... I'm willing to help you debug yours. > A Garmin 18x reports: >Altitude Err:+/- 264 ft Something is terribly wrong with your setup. The Garmin 18x is much, much better than this. I know because the 18x was one of the GPS receivers I brought

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 corrup

Re: [time-nuts] Divide by 3

On 6/8/2016 9:59 AM, Charles Steinmetz wrote: You can achieve substantially lower jitter (phase noise) with a regenerative divider, which also allows you to divide by 3/2 for a 10MHz output. I've built several like that, and they work extremely well. When I was at Agilent, they developed a

Re: [time-nuts] Divide by 3

I remember when we first got a prototype 10816 Mini-Rubidium standard working. We put in on of those old paper strip chart recorders (this was circa 1981). We were pretty cocky about how it went straight down the page. You couldn't do that with quartz. When we came back the next day, you could

[time-nuts] Divide by 3

When I was working on the temperature control feature of Lady Heather, I noticed that I could detect when ever I opened the refrigerator door (in the next room) or when I was in the same room as the Tbolt by looking at the EFC or temperature sensor plots... the Thunderbolt oscillator makes a n