In a message dated 2/27/2007 15:01:44 Pacific Standard Time, [EMAIL PROTECTED] writes:
Sorry, my original post was not very clear - I had only wondered if faster PPS signals might ever help with the measurement each second; I didn't mean to suggest that they might affect the required overall loop time much. ( Thinking back to all the posts a couple of months ago, I should probably resist any urge to comment on the effect of sawteeth on stability for the moment... ) Anyway, I was just curious. It's one of the many things I don't have much time to mess with, so wondered if anyone else had - but apparently not. Angus. Hi Angus, in a traditional PLL where the low-noise reference source is basically "disciplining" a noise oscillator (VCO in this context), the phase comparator frequency is related to the achievable phase noise. Higher comparison frequencies result in lower phase noise. Take a look at National Semiconductor's application notes about this, they give you the underlying math. Analog Devices has great app notes, a PLL simulator etc on their website as well. For a GPSDO, the tables are exactly turned: the reference is much more noisy (short term ADEV) and the VCO is the provider of low short-term phase noise, while the GPS reference provides low long-term phase noise. bye, Said <BR><BR><BR>**************************************<BR> AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
