Atomic Clock & Frequency Counter :)

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Atomic Clock & Frequency Counter :)

Postby Art » November 9th, 2014, 12:43 am

Hi Guys,
I've almost finished my Atomic Clock / Frequency Counter project
based on a Programmable Rubidium Frequency Standard.
The electronics in the video show a frequency being input into the counters
from the gate timer board which divides down a PWM signal from the pic to
provide a 1 Hz (or optional) gate time. This demo shows 1 kHz increments that
hare not yet reset for each display period. The real time clock talks using Roman Black's
sound algorithm for pics and a chip I wrote myself (pic 16F628A) dedicated to playing
samples through a 1 Watt single chip audio amplifier.
Enjoy :)

https://www.youtube.com/watch?v=l9j7VlnjFFk

PCA Layout:
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PCAs Powered Up:
Image

Steampunk Speaker/ Device Frame:
Image[/URL]

Early Device Frame (Coating changed since this picture was taken) :
Image

Early Decade Counter Work:
Image

Early Device Preview:
Image

Cheers, Art.
Art
 
Posts: 45
Joined: October 14th, 2013, 2:46 am

Re: Atomic Clock & Frequency Counter :)

Postby Art » November 14th, 2014, 10:11 pm

Hi Guys :)

This weekend I've assembled a semi manhattan style HF preamp using high frequency LM7171 amp.
Now it works with a 10 MHz RF test frequency.

https://www.youtube.com/watch?v=TSmOOmUaINI

Cheers, Art.


Image
Art
 
Posts: 45
Joined: October 14th, 2013, 2:46 am

Re: Atomic Clock & Frequency Counter :)

Postby Art » November 27th, 2014, 4:34 am

Well here we go.. nearly done :)

YouTube Video:
https://www.youtube.com/watch?v=MZ2H9upQYPI

Image
Art
 
Posts: 45
Joined: October 14th, 2013, 2:46 am

Re: Atomic Clock & Frequency Counter :)

Postby conundrum2063 » November 28th, 2014, 12:44 am

Hi Art, this is indeed fascinating.
Where did you get your rubidium source from?

Also I've been looking into making a variant of the OCXO using HP printer parts, specifically the LM35DZ sensor from behind the print head on the lid sensor PCB.
These show up surplus a lot and are always a good source for parts.

There are a few of the older modules showing up as they were often used in mobile base stations as calibration sources (10MHz and all that) also these use OCXOs too.
conundrum2063
 
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Re: Atomic Clock & Frequency Counter :)

Postby Art » November 28th, 2014, 1:43 am

Hi, there are plenty of rubidium standards on eBay they are pulled from decommissioned cell towers.
You need to do your research they are not all the same. Mine is programmable (0-20MHz),
but unless you open it and remove a bandpass filter the signal is usefull at about 8-14 MHz if it sold as 10MHz.
Others are not programmable and stuck on the freq they are sold as.. which is ok if you wanted the specific frequency.

You know you've got a good one if it achieves a lock quickly after power up.
It should take only a few minutes to indicate atomic lock status.

edit.. re the ovenised Xtals, It appears GPS modules specific to timing are also cheap now, and I've gone that path.
Image
There is currently no way to set this real time clock because a Human can't set the least significant digits for any future comparison.
Rather than lose time resetting the counter, I plan to pre-empt the next second and waste time setting that to the nearest instruction cycle.
Art
 
Posts: 45
Joined: October 14th, 2013, 2:46 am

Re: Atomic Clock & Frequency Counter :)

Postby Art » December 26th, 2014, 10:54 pm

Hi Guys, It’s supposed to be a project log.. so ...

The latest is audio coupled DTMF control with Sony tie clasp microphone :)
There is another board about 1/3 populated underneath the micro controller board.

https://www.youtube.com/watch?v=RXlqqFkj0fI


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Last edited by Art on January 1st, 2015, 8:08 pm, edited 1 time in total.
Art
 
Posts: 45
Joined: October 14th, 2013, 2:46 am

Re: Atomic Clock & Frequency Counter :)

Postby Art » January 1st, 2015, 8:07 pm

Finally got it tested with 10 MHz input signal and no error is introduced :) even without the preamps being shielded.

https://www.youtube.com/watch?v=ZoakP6pwlhU
Art
 
Posts: 45
Joined: October 14th, 2013, 2:46 am

Re: Atomic Clock & Frequency Counter :)

Postby GingerBiscuit » March 9th, 2016, 4:10 am

Art wrote:Hi Guys, It’s supposed to be a project log.. so ...

The latest is audio coupled DTMF control with Sony tie clasp microphone :)
There is another board about 1/3 populated underneath the Phen375 review https://skinnyexpress.com/phen375-review-and-results micro controller board.

https://www.youtube.com/watch?v=RXlqqFkj0fI

Image


Damn, that looks cool. Couldn't watch the video as it's unavailable according to YT but from the pic this looks awesome. Would definitely be something to talk about with friends over.
GingerBiscuit
 
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