[time-nuts] The ultraAtomic clock for home
kb8tq at n1k.org
Fri Apr 7 13:11:05 EDT 2017
Since it’s a magnetic stepper motor, how about a magnetic (coil) sensor?
Based on past data, anything past 1us is massive overkill. A mag sensor
with a ~100 KHz bandwidth should be a do-able sort of thing. A couple dozen
turns of wire around a suitable ferrite rod might be enough.
> On Apr 7, 2017, at 1:03 PM, Tom Van Baak <tvb at LeapSecond.com> wrote:
>> Very good catch it is *not* the cme8000 chip. Thats a classic am receiver.
>> It is the everset chip. Sorry for mis-leading.
> Hi Paul,
> I can confirm (from talking with the guys backing it) that, yes, it's the EverSet ES100, in die form (CoB). I believe you and I have both used the early Xtendwave dev kits with the ES100 as SMT part. It's nice to see the chip still lives and finally made it to a product!
> I uploaded more ultrAtomic info and tear-down photos:
> I encourage those of you who just bought these clocks to do some experiments. The obvious ones are:
> 1) See how long it takes to acquire the correct time, at all sorts of different and difficult environments, compared to the traditional WWVB clocks. Check for off-by-one second, or minute, or hour errors.
> 2) See how accurate they really are. For clocks like this I use a variety of piezo sensors (feel the tick), acoustic sensors (hear the tick), optical sensors (see the tick), and mostly electrical sensors. Some of these are passive (non-destructive) timings and good enough. Others require some level of disassembly but are more precise. For a stepper motor clock it's easy to tap onto the coil connections and get a sharp pulse every second or two. Then use a time interval counter, or picPET, or TICC, or PC-based PPS-capture to collect readings. Note the signal level is usually low power and below typical TTL levels, and they do NOT drive 50R!
> If all goes well, we can soon talk about a time-nuts special where we get someone to make a timing board or disciplined timing board based on the ES100 chip. The bad news is that at the same price it would be like a million times worse than GPS. The good news is that lots of applications need only ms level timing; there are places where WWVB is receivable and GNSS is not; and then there's the redundancy and low-power factor.
> ----- Original Message -----
> From: "paul swed" <paulswedb at gmail.com>
> To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
> Sent: Friday, April 07, 2017 5:08 AM
> Subject: Re: [time-nuts] The ultraAtomic clock for home
> Very good catch it is *not* the cme8000 chip. Thats a classic am receiver.
> It is the everset chip. Sorry for mis-leading.
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