RetiredHAL
New Member
Hi, I have spent a day or so (on this site and the internet) trying to determine which is the better approach to get an accurate clock. (seconds over a year)
I only want to consider the arguments relating to using a 32.768 Khz crystal as opposed to a 4.194304 Mhz crystal.
I am not interested in special oven or temperature controlled or software driven correction method ICs. I am only really interested in 4000 Ic series usage.
I have looked at almost everything, but readily admit that my maths skills are not sufficient to understand the integration, differentiation and calculus involved to make a valued judgement. I refer to Uni papers and other technical treatises on this subject.
I note (drooling mouth and lips) the Oliverb's Clock and the accuracy he has achieved.
This is an academic exercise. The 32kHz Xtal is used in all battery operated clocks and watches and keeps exceptionally good time.
The 4.19Mhz Xtal is less widely used but is still a natural 2^n divisible number.
Given that the Xtal manufacturers specify +/- 50-100 ppm error in the cut crystal is there an advantage using either Xtal?
I have done numerous exercises calculating seconds in a year, with slightly different error rates, but am unable to derive at a definite answer.
My other question of course is how do you check the time. I do not not have ready access to GPS and I am not sure that the "time pips" in Australia can be traced to a Standard.
Cheers
RetiredHAL
I only want to consider the arguments relating to using a 32.768 Khz crystal as opposed to a 4.194304 Mhz crystal.
I am not interested in special oven or temperature controlled or software driven correction method ICs. I am only really interested in 4000 Ic series usage.
I have looked at almost everything, but readily admit that my maths skills are not sufficient to understand the integration, differentiation and calculus involved to make a valued judgement. I refer to Uni papers and other technical treatises on this subject.
I note (drooling mouth and lips) the Oliverb's Clock and the accuracy he has achieved.
This is an academic exercise. The 32kHz Xtal is used in all battery operated clocks and watches and keeps exceptionally good time.
The 4.19Mhz Xtal is less widely used but is still a natural 2^n divisible number.
Given that the Xtal manufacturers specify +/- 50-100 ppm error in the cut crystal is there an advantage using either Xtal?
I have done numerous exercises calculating seconds in a year, with slightly different error rates, but am unable to derive at a definite answer.
My other question of course is how do you check the time. I do not not have ready access to GPS and I am not sure that the "time pips" in Australia can be traced to a Standard.
Cheers
RetiredHAL