On 7/17/06, trossin wrote: > > Back in the old days we would buy a 22pF trimmer cap and use a screw driver > to tune the frequency. Today you can do it with software. > > The other fun fact is that the frequency of the oscillator is temperature > dependent. Years ago folks would put their crystals in mini crystal ovens > and regulate the temperature to get a very stable source. > The modern solution is a "TCXO" or temperature-compensated crystal oscillator. You can buy them with a few ppm accuracy over temperature for less than $10 (digikey, ones). Or steal one from a digital cell phone. The cell phone specs require a rather accurate oscillator. Regards, Mark markrages@gmail -- You think that it is a secret, but it never has been one. - fortune cookie -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist