Hi A lot of folks get surprised by the phase noise at the output of a narrowband filter …… You do need a pretty wide “don’t care” region past the cutoff.
Bob > On Sep 16, 2021, at 8:24 AM, Mike Feher <[email protected]> wrote: > > Back in the late 80's we were building a synthesizer with extremely strict > phase noise characteristics at an output of 44 GHz. At the output of our > ultra low noise Rubidium, we also added a 100 Hz BW crystal filter. At the > time, even though Dave Allen was involved, our spec was such as the noise > power was not to exceed a certain power lever integrated over specified BW, > without any exclusion band around the carrier. Lincoln Lab built the > feasibility model and I manually integrated their noise power and they > exceeded the limit by 10 dB. So, I argued that they needed to give us an 8 > KHz exclusion window in the spec, and won. Regards - Mike > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell NJ 07731 > 848-245-9115 > > -----Original Message----- > From: Francis Grosz <[email protected]> > Sent: Wednesday, September 15, 2021 1:06 PM > To: [email protected]; [email protected] > Subject: [time-nuts] Re: time-nuts Digest, Vol 209, Issue 14 > > Marek, > > Following Mark's suggestion, if you really want to clean up the 10 MHz > you might want to look at the AXTAL AXPLO10. Not a cheap solution, but > it's specifically designed to do what you're looking for. > > Francis Grosz > > > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send an > email to [email protected] > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
