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

[Alan Melia]

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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