I do not understand why the passband ripple would be of any consequence in the big (or small as we typically talk about) picture. During any measurement interval, it will be a constant, for all practical purposes, including ours. A measurement at a different time, at a different temperature that may adversely affect where the ripple is, it will certainly create a slightly different amplitude and phase delay, however, again, a constant through the measurement process, not affecting the result. When we were designing the system I mentioned previously, both Dave and Fred of NIST were in assistance, as well as the staff of the relevant departments of MIT's LL, and no one saw any issues. Regards - Mike
Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ 07731 732-886-5960 -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Leigh L. Klotz, Jr. WA5ZNU Sent: Wednesday, June 23, 2010 6:15 PM To: did...@cox.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FRS-C TTL / sine outboard filter question Thank you, Didier. That pretty much sums it up. I was aware of the signal level issue but didn't consider that passband ripple would be temperature sensitive. It's fun learning to think in the long time domain. In the meantime I've found a 10 mbit ethernet ISA card in my office and will follow Robert G8RPI's suggestion to use G4HUP's document to obtain a ready-made 10 MHz filter from it. Plus as a bonus the box had a BNC T connector in it. Leigh/WA5ZNU _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
