[time-nuts] accurate 60 hz reference chips/ckts

Tim Shoppa tshoppa at gmail.com
Thu Dec 14 18:50:33 EST 2017


That’s not a problem, that means you’re phase locked instead of just frequency locked.

This is the phase-nuts mailing list, right? :-)

Tim N3QE

> On Dec 14, 2017, at 6:19 PM, Alan Melia <alan.melia at btinternet.com> wrote:
> 
> 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" <j99harman at gmail.com>
> To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
> 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 <hmurray at megapathdsl.net> wrote:
>>> 
>>> 
>>> apolloeme at gmail.com 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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> 
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