Digital Clock

I have a crystal oscillator that I'm testing on the bench now. It's currently drifting at a rate of about 0.15ppb (parts per billion) per hour.

So in 1 year it will change by about 1.2ppm (parts per million)

Although I'm hoping it will drift less when it has settled down.

Which means it should be less than 20 seconds out after 1 year.

I had been wondering if you could make a clock that never needs resetting in a lifetime  - it would need to 100x better than my oscillator.

What kind of clock are you thinking of ?

MK

I have a crystal oscillator that I'm testing on the bench now. It's currently drifting at a rate of about 0.15ppb (parts per billion) per hour.

So in 1 year it will change by about 1.2ppm (parts per million)

Although I'm hoping it will drift less when it has settled down.

Which means it should be less than 20 seconds out after 1 year.

I had been wondering if you could make a clock that never needs resetting in a lifetime  - it would need to 100x better than my oscillator.

What kind of clock are you thinking of ?

MK

Hi Michael,

It would be awesome to see a photo of it if it's not sensitive to share it. I'm guessing construction techniques within its enclosure matter a lot to make sure components don't flex etc.

Apparently Harrison No. 5 achieved 1/14th of a second a day, incredible to think that the temperature compensation was that precise with the metalworking techniques of the day! http://www.surveyhistory.org/john_harrison's_timepiece1.htm

I own a Timex watch that just happens to have an awesome crystal. It wanders 2 or 3 seconds per year for the first 3 years of a battery and gains about 10 seconds in the 4th year - when it is time to change the battery. I no longer wear a watch, but I still keep that lucky watch. I suspect it has larger excursions due to temperature, but they seem to average out over the course of a year.

The really awesome part is the cheapness and accessibility of the bits - no secrets.

I'll do a blog as soon as I get time

MK