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

Vlad time at patoka.org
Fri Dec 15 12:01:19 EST 2017



I have one of my project boxes, which monitor the main freq. Here is 
graph which reflect the time difference between of RTC (based on number 
of pulses from OCXO) and the "MAIN TIME" which is based on number of 
zero-cross events.
The observation period is 486 hours.




On 2017-12-14 23:13, Jim Harman wrote:
> On Thu, Dec 14, 2017 at 10:53 PM, Bob kb8tq <kb8tq at n1k.org> wrote:
> 
>> 
>> 
>> Of course this *assumes* an electronic approach. Given that it’s 
>> moving
>> pretty slow and you
>> only are looking at fractions of a millisecond, one *could* do an 
>> electro
>> mechanical design …...
>> 
>> Bob
>> 
>> There is interesting background on power grid frequency/time 
>> adjustment
> procedures here
> https://en.wikipedia.org/wiki/Utility_frequency#Time_error_correction_(TEC)
> 
> and here
> https://en.wikipedia.org/wiki/Electric_clock#Accuracy

-- 
WBW,

V.P.
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