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

[Wayne (gmail)]

https://www.google.com/amp/s/spectrum.ieee.org/semiconductors/materials/to-build-the-worlds-smallest-atomic-clock-trap-a-nitrogen-atom-in-a-carbon-cage.amp.html

> On Dec 8, 2017, at 10:38 AM, Ulrich Rohde via time-nuts  
> wrote:
> 
> Impressive, Ulrich 
>  
> In a message dated 12/8/2017 12:41:23 PM Eastern Standard Time, 
> tom.n...@gmail.com writes:
> 
>  
> There's an interesting article in the December 2017 issue of IEEE Spectrum.
> 
> 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,
> and they've developed a method to also isolate it from external magnetic
> fields.
> 
> They have not incorporated the material into a working standard, but have
> licensed the chemical fabrication technology to at least one manufacturer.
> The idea is to make a chip-scale atomic frequency reference.
> 
> -- Tom, N5EG
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Re: [time-nuts] LPRO-101 BITE (~lock) Signal Always Low

[Wayne (gmail)]

The BITE signal is the only way to to know if it has a lock...

Wayne

> On Mar 22, 2016, at 4:37 AM, Bob Camp  wrote:
> 
> Hi
> 
> There are probably a dozen or more things that contribute to the BITE output. 
> It could be
> a regulator out of range. It also could be the VCXO nearing tune limit. If 
> the unit locks up and
> seems to work, I’d ignore it and move on.
> 
> Bob
> 
>> On Mar 21, 2016, at 9:42 PM, Wayne Holder  wrote:
>> 
>> I have a surplus LPRO-101 that seems to power up OK.  The power draw starts
>> at 1.7 Amps and then, after a few minutes, drops down to 600 mA, or so and,
>> after this startup, the output shows a 10.000 MHz signal thats 's
>> accurately as I can measure it.  The lamp voltage is 6.2 volts, which seems
>> within spec.  However, the BITE signal that's supposed to indicate lock
>> with a LOW level is always LOW and never changes.  The docs say that BITE
>> signal should start at a HIGH level to indicate no lock and then drop to a
>> LOW when lock is obtained.  So, this behavior seems all wrong.
>> 
>> I opened the case and observed the purple glow of the lamp and probed
>> around IC U401, which buffers the BITE signal, and saw the same signal LOW
>> level.  U401 is getting 5 volt power and the inputs to the AND gate used as
>> a buffer for the BITE signal match what I'd expect.  But, lacking a proper
>> schematic, I'm not sure how to trace this back to the problem.  Has anyone
>> ever seen a symptom like this with an LPRO101?
>> 
>> Wayne
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