Re: Looping Binary Counter, Stable 32768 oscillator

Sounds like a good idea but at 4 bits per counter thats a lot of counters to use.
It would be so nice to find a single chip that would be a 20 bit counter but I know of none.
I am wary of sending 3.6MHz any distance because
of possible RFI generation.

Sincerely;
gmvoeth

"James T. White" <SPAMjtwhiteGUARD@xxxxxxxxxx> wrote in message news:42ea9f69$0$543$a726171b@xxxxxxxxxxxxxxxxxx
> "GMV" <gmvoeth@xxxxxxxxx> wrote in message
> news:e664$42ea52e8$4fea0a0$5983@xxxxxxxxxxxxxxxx
>> I am in need of a circuit that will place minute mark
>> ,second 59 or second zero of UTC, into my homebuilt circuit
>> for calibration purposes. I have thought of possibly building
>> a 32768Hz oscillator and using a looping binary counter that can be
>> calibrated using WWV or WWVB but this all sounds silly to me
>> since there must be calibration clocks already out there.
>> I need either one with a TTL output or even better an FET switch or something
>> like that with a mark I can feed directly into the back end of my
>> circuit just before the signal hits the A/D converter.
>> The stability of the oscillator would be most important
>> not to deviate more than +/-0.03 Hz.
>> My laptop has a RTC that looses one second of time every four point five hours
>> so it is completely unsuitable for anything other than getting the time
>> close enough to understand what the calibration mark means.
>>
>> Could someone who is an engineer provide me with
>> a schematic to do this ?
>> The basic idea seems simple for those educated in the EE field.
>> It is the stable oscillator that eludes me.
>>
>> Any help here is appreciated.
>> Sincerely;
>> gmvoeth@xxxxxxxxx
>>
>>
>
> You might see if you can pick up a HeathKit GC-1000 cheap off eBay. The GC-1000
> synchronizes the local oscillator with WWV signals at 5, 10 or 15 MHz and has a
> 3.6 MHz TTL output. There was an option for outputting an ASCII time stream on
> an RS-232 port, too. With an external antenna in the attic, my GC-1000 stays
> "synchronized" to WWV most of the time and the few times I've checked the output
> with a frequency counter has been dead on 3.6 MHz.
>
> Then all you would need is a simple TTL counter chain to divide by 3,600,000 and
> you have a 1 pps signal.
>
> --
> James T. White
>
>


.

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