I sure do agree, that with very low data rate systems it is significant. In fact, when David Allan & Fred Walls came up with the proposal of using this measurement as an FOM for oscillators over 30 years ago, digital communication rates were slow, and, the measurement was a good one. Due to the filtering process within ADEV by collecting and integrating a large number of samples, has a filtering effect of its own. Therefore, it can, and will, miss the fact that there may be instantaneous phase transitions that could cause havoc with high data rates and higher order PSK modulation schemes. So, again, I apologize, as I should have mentioned higher data rates. However, you must admit that your application, while extremely critical, is in the minority. I like to use the example of something like DirecTV. Here, they use a down-converter that utilizes a free running DRO, that is ridiculously noisy, and, varies all over in frequency, especially over the temperature ranges it subjected to. In spite of all of that, one gets a perfect pictures. Regards - Mike
Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-901-9193 cell -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of jimlux Sent: Friday, November 12, 2010 11:33 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT loosing things Mike Feher wrote: > Relax - we all need a little humbleness and humor every once in a while. > Besides, I am honestly beginning to doubt the usefulness of ADEV in today's > communications systems, and yet it seems we are stuck on it. Regards - Mike > > You just need to look at a different kind of communication system. If you're working at 8 bps like I do, or you want to measure the distance to a spacecraft around Saturn with an accuracy of millimeters, ADEV is important. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
