Re: [time-nuts] Relationship of frequency to stability

Hi For something like a crystal oscillator, there is a relation between frequency and resonator Q. That gives you a loose correlation between stability and oscillator frequency. Beyond that, there are substantial differences between the technologies you are comparing. That is the main source

Re: [time-nuts] PPS sync

That makes complete sense, it’s not disciplining anything, just pumping out the PPS and reporting the variance. I don’t know why I didn’t think of it. It’s interesting how it jumps around from PPS to PPS. Thank you, Jerry > On Jun 7, 2017, at 2:57 AM, Hal Murray

Re: [time-nuts] HP8640

There is, or was, a member of the Yahoo hp_agilent forum who was making metal replacement gears for the HP8640. I believe several members replaced the plastic gears with the new metal ones and were able to bring their instruments back to life. DaveD On 6/7/2017 8:56 AM, Bert Kehren via

Re: [time-nuts] Relationship of frequency to stability

There is no direct relationship between frequency and stability. For any given frequency, the stability is determined to a large extent by the technology used for the oscillator. For instance, at 1 kHz, a quartz crystal is normally more stable than a tuning fork which is normally better than a

[time-nuts] TruePosition on the Arduino

If you run it on a system with an accurately set clock, Lady Heather can measure the offset (and standard deviation and ADEVs) between the time in the receiver time code message and when the last byte of the time code message comes in. It also calculates a histogram of the message offsets.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

Hi There is a gotcha with the initial assumption: You want the loop to be *quiet* at a level well below 0.1C. If it is bouncing around that much, the second order (rate defendant) tempco of a normal crystal will become a pretty major issue. Simple rule of thumb - add at least two bits past

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

One question for the control theory experts. Assume me goal is to regulate temperer of an aluminum block to within 0.1C, how good must my ADC be? Is an effective 6-bits good enough? It seems to me the problem with fewer bits is only quantization noise. Lets assume 6-bits. This is 1 part in

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

The good news is that for oven control, you can typically filter the heck out of the data and the noise may actually help you with dithering if it's fairly random, so you should be able to get close to the specs. The main thing you need is stability, linearity should not be a factor. One

Re: [time-nuts] HP8640

Hello Ulrich, I have an 8640 I was going to put up for sale in the next few weeks. It’s in almost perfect condition. All of the gears are intact with no cracks or splitting. I think this SG may have been in a lab environment most of it’s lifetime. Contact me off list if you are interested.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

albertson.ch...@gmail.com said: > Assume me goal is to regulate temperer of an aluminum block to within 0.1C, > how good must my ADC be? Is an effective 6-bits good enough? I don't think you are asking the right question. You can build a control loop with a 1 bit ADC. Think of your typical

[time-nuts] uC ADC resolution (was: Poor man's oven)

Another thing to watch out for on processor ADCs is their performance near the supply rails... the AVR ADCs are particularly entertaining below around 300 mV (with a 5V Vref). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] HP8640

Yes I need one for 1 day, not to keep In a message dated 6/7/2017 3:19:37 P.M. Eastern Daylight Time, scmcgr...@gmail.com writes: Ulrich I have an operational 8640 Content by Scott Typos by Siri > On Jun 7, 2017, at 11:35 AM, Dave Daniel wrote: > > There is, or

Re: [time-nuts] HP8640

Ulrich I have an operational 8640 Content by Scott Typos by Siri > On Jun 7, 2017, at 11:35 AM, Dave Daniel wrote: > > There is, or was, a member of the Yahoo hp_agilent forum who was making metal > replacement gears for the HP8640. I believe several members replaced the

Re: [time-nuts] Poor man's oven

On Tue, 6 Jun 2017 19:07:29 -0700 "Richard (Rick) Karlquist" wrote: > In the E1938A oscillator, we used a PIDI^2 loop. IOW, a PID > plus a double integrator. This was Len Cutler's idea. > Once the constants were dialed in, this worked phenomenally > well in terms of

[time-nuts] HP 8640 Brass replacement gears

I can provide brass gears for your HP 8640 Signal generator. If any members of the list are interested, please contact me off list. wa0...@arrl.net I will be happy to provide the information. 73 Paul K. WA0BAG -- Paul K. WA0BAG ___ time-nuts

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

On Wed, 7 Jun 2017 15:25:38 -0400 Charles Steinmetz wrote: > Chris wrote: > > > Assume me goal is to regulate temperer of an aluminum block to within > > 0.1C, how good must my ADC be? Is an effective 6-bits good enough? > > > > * * *If I scale the input to the

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

On Tue, 6 Jun 2017 16:43:30 -0700 Chris Albertson wrote: > > . Heck, the STM32F4xx have so much internal noise that the ENOB > > of their ADC is below 6bit... so low that they even had to write an > > appnote on how to do averaging to get back to the 12 bits the ADC is

Re: [time-nuts] PPS sync

je...@hanler.com said: > Chris, I think you are onto something. Running Lady Heather on this unit I > see a line under “receiver” with the term “SawT” and a parameter of > 24ns. > So if we combine this information with what you teach below, it’s starting > to look like maybe the M12

Re: [time-nuts] TruePosition on the Arduino

sobo...@sippysoft.com said: > SO_BINTIME was ENOTSUPP with IPv6 from the day one. Thanks. Is that a literal ENOTSUPP? Should I get an error from setsockopt? Or is that just shorthand for not-implemented? Do you want a bug report? If nothing else, the man page should be updated. Just

Re: [time-nuts] TruePosition on the Arduino

Argh/sorry. I fatfingered something. Wrong list. -- 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

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

Chris wrote: Assume me goal is to regulate temperer of an aluminum block to within 0.1C, how good must my ADC be? Is an effective 6-bits good enough? * * *If I scale the input to the ADC such that it os 1.0C from 0 to 63 counts then each cunt is 1/64 C which is about 6 times better

Re: [time-nuts] Poor man's oven

Hi Keep in mind that on a per cubic inch basis, copper is right up there for creating a thermal mass …. Bob > On Jun 7, 2017, at 5:51 PM, Attila Kinali wrote: > > Hoi Rick, > > On Wed, 7 Jun 2017 14:21:52 -0700 > "Richard (Rick) Karlquist" wrote: > >

Re: [time-nuts] Poor man's oven

Hoi Rick, On Wed, 7 Jun 2017 14:21:52 -0700 "Richard (Rick) Karlquist" wrote: > Actually, the oven mass of the E1938A is much heavier than the > 10811 and is made of copper to boot. [...] > The crystal case is well connected to the oven mass and gets > heated by

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

On Wed, 7 Jun 2017 22:20:50 +0100 Peter Vince wrote: > > Additionally: if I would set out to build my own OCXO today, I would > > go and buy one of those lunch thermos flasks to house everything. Their > > isolation is higher than anything you can easily build yourself,

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

Hi Consider that a lot of the heat flow is through the glass wall of the vacuum gizmo. You want to tie your heater(s) to it in order to create an iso-thermal “wall”. Often this is done by gluing the whole assembly together. In addition, you probably also want a foam plug in the end of the

Re: [time-nuts] Poor man's oven

On 6/7/2017 1:09 PM, Attila Kinali wrote: makes the PI loop better behaved. Also the thermal mass of the crystal holder is quite small. Especially compared ot the 10811. Actually, the oven mass of the E1938A is much heavier than the 10811 and is made of copper to boot. Due to the flat

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

On 7 June 2017 at 21:40, Attila Kinali wrote: > > Additionally: if I would set out to build my own OCXO today, I would > go and buy one of those lunch thermos flasks to house everything. Their > isolation is higher than anything you can easily build yourself, > especially at

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

Hi > On Jun 7, 2017, at 4:40 PM, Attila Kinali wrote: > > On Wed, 7 Jun 2017 15:25:38 -0400 > Charles Steinmetz wrote: > >> Chris wrote: >> >>> Assume me goal is to regulate temperer of an aluminum block to within >>> 0.1C, how good must my ADC be?

Re: [time-nuts] Poor man's oven

Hi The crystal enclosure may (or may not … who knows ..) be back filled with a low level of helium. It does not take much of a backfill for conduction inside the crystal holder to dominate the heat transfer vs radiation transfer. Bob > On Jun 7, 2017, at 5:21 PM, Richard (Rick) Karlquist

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

For under $20 you can get a OCXO with Si5351A multi output oscillator chip from QRP-Labs. http://www.qrp-labs.com/ocxokit.html No idea just how good it is but this link gives insight into how it was developed. Designed for WSPR radio transmissions. GPS discipline can be added.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

Hi Metal actually makes things a bit worse since it has a lower thermal resistance than glass. This is also why a high performance dewar is made from glass rather than metal. Yes, you can go to weird stuff like titanium (it has been done). You can’t afford that …. If you fill the entire

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

On 6/7/17 7:35 PM, Bob kb8tq wrote: Hi Metal actually makes things a bit worse since it has a lower thermal resistance than glass. This is also why a high performance dewar is made from glass rather than metal. Yes, you can go to weird stuff like titanium (it has been done). You can’t afford

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

Hi Folks, This discussion of temperature measurement with ADCs has crossed into my professional life and without being too much of a commercial plug just wanted to mention that I support Linear Technology's temp-to-bits family of ICs: LTC2983, LTC2984, LTC2986. Overview: each part has 3

Re: [time-nuts] MCXO and dual mode

Hi Yes, you run both modes at the same time. You wire up two oscillator circuits to the same crystal. One runs at the fundamental and the other runs at the third overtone. The two have a different temperature coefficient. (yes, that’s a bit weird, but it is true). The “offset” between the

[time-nuts] Relationship of frequency to stability

SHORT VERSION: I’ve been trying to figure out what the relationship is between frequency and stability - if there is one - that is, why oscillators with higher frequencies tend to be more stable. LONG VERSION: I got into this by building a home-brew NTP server using a cesium-disciplined

Re: [time-nuts] HP8640

I think it will be difficult to find a well working 8640, plastic gears will have by now totally disintegrated. What part of it do you need, I may have something left. Bert Kehren In a message dated 6/6/2017 9:06:05 P.M. Eastern Daylight Time, time-nuts@febo.com writes: Hi , I am