RetiredHAL
New Member
Hi, I would like to know which would be the more accurate timekeeper.
I wish to make a clock using (well "almost" discrete) components using 4xxx cmos IC's .
I have looked at Oliverb's clock and would like to do something similar.
I would also like to incorporate a "failsafe" battery back up to keep the clock running and include a good am/fm wake up radio ic .
Yes i can buy all that for $90 , but that is not the point.
My first question is -- which is the more accurate , a 10Mhz Xtal at 30ppm error or a Tuning fork Xtal (32.768Khz) at 20ppm accuracy over a 6months or a year. I have tried to do the maths but unfortunately my math skills have deserted me to come to a definitive answer
I wish to make a clock using (well "almost" discrete) components using 4xxx cmos IC's .
I have looked at Oliverb's clock and would like to do something similar.
I would also like to incorporate a "failsafe" battery back up to keep the clock running and include a good am/fm wake up radio ic .
Yes i can buy all that for $90 , but that is not the point.
My first question is -- which is the more accurate , a 10Mhz Xtal at 30ppm error or a Tuning fork Xtal (32.768Khz) at 20ppm accuracy over a 6months or a year. I have tried to do the maths but unfortunately my math skills have deserted me to come to a definitive answer