[time-nuts] Re: time-nuts Digest, Vol 209, Issue 14

[Bob kb8tq]

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 <mfeher at eozinc.com> 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 <nolafg47 at gmail.com> 
> Sent: Wednesday, September 15, 2021 1:06 PM
> To: time-nuts at lists.febo.com; marek.dorsic at gmail.com
> 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 -- time-nuts at lists.febo.com -- To unsubscribe send an email to time-nuts-leave at lists.febo.com
> To unsubscribe, go to and follow the instructions there.