Re: [time-nuts] IEEE Spectrum - Dec 2017 - article on chip-scale atomic frequency reference

On Fri, 8 Dec 2017 09:40:29 -0800 Tom McDermott wrote: > Researchers at Oxford U. have fabricated an atomic reference based on > a single nitrogen molecule inside a 60-atom carbon sphere ("Fullerene"). > The cage of carbon isolates the nitrogen from external electric fields,

Re: [time-nuts] European Electronics Systems Radio Clock Model 100

Hi Steve, The name EES, or European Electronics Services Ltd, has been used more than once, latest registration appears to be only about a year ago, and might well have been used at one time by Siemens, but I think the company you're looking for is, or was, EES Technology Ltd. This

Re: [time-nuts] Fluke/Pendulum PM6680/CNT-80 measurement instability/outliers

On Thu, 14 Dec 2017 22:08:01 -0600 Bill Byrom wrote: > I have a few questions about your setup: > (1) What is the waveform shape you are measuring? Are you measuring a > square wave (or some other duty cycle waveform with fast rise and > falling edges)? Or is it a sinewave

Re: [time-nuts] Determining Allan Deviation From Interpolated Peak Frequency Readings

Hey Mark On Wed, 6 Dec 2017 15:43:49 -0700 Mark Goldberg wrote: > https://sites.google.com/site/perseusmods/ > and > https://sites.google.com/site/spectrumlabtesting/ > > using wide FFT bins and Spectrum Lab's peak frequency interpolation > function. I would appreciate

Re: [time-nuts] IEEE Spectrum - Dec 2017 - article on chip-scale atomic frequency reference

> Le 15 déc. 2017 à 14:06, Attila Kinali a écrit : > > On Fri, 8 Dec 2017 09:40:29 -0800 > Tom McDermott wrote: > >> Researchers at Oxford U. have fabricated an atomic reference based on >> a single nitrogen molecule inside a 60-atom carbon sphere

Re: [time-nuts] accurate 60 hz reference chips/ckts

My setup is pretty simple indeed. This is 9.830400MHZ OCXO which clocking MCU. Then it is Zero-Cross detector which connected to capture timer. The MCU counting the intervals between of each zero-cross event and number of events occurred. if (htim->Instance == TIM5 && htim->Channel ==

Re: [time-nuts] accurate 60 hz reference chips/ckts

I have one of my project boxes, which monitor the main freq. Here is graph which reflect the time difference between of RTC (based on number of pulses from OCXO) and the "MAIN TIME" which is based on number of zero-cross events. The observation period is 486 hours. On 2017-12-14 23:13,

Re: [time-nuts] accurate 60 hz reference chips/ckts

I'm surprised Vlad is seeing as much as six seconds differential but maybe I don't understand the experiment. I've done measurements of the line frequency here in California and never seen much variation. Jeremy On Fri, Dec 15, 2017 at 9:02 AM Vlad wrote: > > > I have one of

Re: [time-nuts] IEEE Spectrum - Dec 2017 - article on chip-scale atomic frequency reference

On Fri, 15 Dec 2017 17:17:31 +0100 Mike Cook wrote: > > The original paper in question is [1]. As with the nitrogen vacancy > > clocks, which also trap nitrogen within a Carbon lattice, these have the > > drawback of quite high temperature coefficients, Harding et al

[time-nuts] accurate 60 hz reference chips/ckts

Your mains zero-crossing routine should have some sanity filtering built in to ignore pulses that are too short and perhaps fix up ones that are too long (i.e missing pulse). Power line signals are notoriously noisy/glitchy... particularly around the zero crossings.

Re: [time-nuts] accurate 60 hz reference chips/ckts

Hi It depends a *lot* on just where you are and how the “gird” is managed. Many years ago, we figured out that the local power company corrected things between 4 and 5 PM. It became a habit to fire up WWV and watch them slip seconds one way or the other. A ten second delta was not at all

Re: [time-nuts] accurate 60 hz reference chips/ckts

Jeremy wrote: I'm surprised Vlad is seeing as much as six seconds differential but maybe I don't understand the experiment. I've done measurements of the line frequency here in California and never seen much variation. When was the earliest time (year) you started looking seriously at the