I dont think working that way would give a stable clock in the UK. Our
frequency can vary more than the US but the number of cycles between 0800 on
one day and the next is mandated to be correct (I presume +/- 25 :-)) ). So
you would be chasing a moving target, and at no time of the day need the
frequency be 50.000Hz
Alan
G3NYK
----- Original Message -----
From: "Jim Harman" <[email protected]>
To: "Discussion of precise time and frequency measurement"
<[email protected]>
Sent: Thursday, December 14, 2017 10:08 PM
Subject: Re: [time-nuts] accurate 60 hz reference chips/ckts
Since the power line has the desired long term stability but is poor on
the
short term, I wonder if a solution might be to use it as the reference for
a "power line disciplined oscillator."
You would want a filter time constant of several hours in the control loop
to smooth out the variations in the 60 Hz.
Or it might be easier to rip the guts out of the Radio Shack clock, just
keeping the display, and drive the display with an Arduino and a DS3231
RTC
chip as the reference.
On Thu, Dec 14, 2017 at 4:05 PM, Hal Murray <[email protected]>
wrote:
[email protected] said:
> Want to provide an accurate (relatively accurate) 60 hz reference to
> the
> chip. Some room inside for custom modifications. Does a TCXO or
similar
> exist in a small package that provides 60 hz ticks?
I doubt if you will find a TCXO that puts out 60 Hz. But it's only one
chip
to make a divider. The trick is to do it in software rather than
hardware.
The real question is what sort of error pattern are you interested in.
The
power company has good long term stability. How good is your TCXO? It
would
be fun to play with the numbers. On the other hand, can you derive your
60
Hz from a GPSDO?
--
These are my opinions. I hate spam.
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--Jim Harman
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