Yep, that's what I was thinking.. If the line frequency gets bad enough, I'll add little TCXO 60khz oscillators to the front of my clocks and cut the trace that used to get the 60khz from the AC. This is a very well reasoned and clearly thought out illustration, and it demonstrates nothing quite so much as that a regular crystal is a terribly inaccurate way to run a clock. If you post the source code, I'd definitely use it. :D
-Adam On Mon, Jun 27, 2011 at 5:09 PM, threeneurons <[email protected]>wrote: > > If you can change the input source (3.58MHz xtal), or tweak it, you > might just want to leave things alone. > > There are 525,960 minutes in a year, on average. 525,600 for a normal > year, and 527,040 for a leap year. Being off 20 minutes in a year > works out to ~38ppm (East Coast). 8 minutes comes out to 15ppm (West > Coast). A typical crystal has 30 to 50 ppm accuracy, or between 15 to > 26 minutes off, in a year. You'll get no improvement with a common > crystal. You might just as well just stick with the line sync, and > just occasionally hit that minute button, to correct the time. > > That module won't help you unless you swap out that xtal, and tie a > TCXO to the clock input. Of course, you'll need to match the > frequency, or write your own uC code. A TCXO has an initial accuracy > in the 1ppm to 2.5ppm territory. Even when extra errors, such as aging > coming into play, you're still a lot better off than using a cheap > xtal. > > I actually use to sell a coded uC (a tiny12 in fact) on eBay, that > outputed 50Hz, 60Hz, and 1Hz. Sold it for $5 each. Maybe I should just > post the source code, to screw with that guy. Code is pretty trivial. > > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/neonixie-l?hl=en-GB. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
