[time-nuts] phase noise webinar from IEEE MTT-S

[Attila Kinali]

On Tue, 13 Oct 2020 12:46:46 -0500
"Bill Byrom" <time at radio.sent.com> wrote:

> I just attended this webinar. It focused on oscillator design
> theory and the results the author had achieved for various 
> specific projects. He discussed in general amplitude limiting to 
> reduce amplitude noise, with the result that we only need to worry 
> about phase noise in most cases. Very little time was spent on 
> atomic clocks - he gave three slides which showed Rubidium 
> resonance lines and vapor cells and a block diagram but there was 
> little else. He discussed flicker noise but didn't get into the 
> physical cause of that phenomenon. He spend a bit of time 
> discussing frequency tweaking using varactor phase shifters.

A couple of notes here:

Everard is a great practical guy. He knows oscillators and he
knows them well. The papers comming out his group are great
resources on how to build oscillators for various applications.
I haven't had time to read his book yet, but the few pages I
looked at gave a very good impression. If you ever meet him
and have questions, he is very enthusiastic in answering them.

About flicker noise: over a century after we discovered them,
we still do not understand how it comes to be. A bit simplified,
all we know is that defects increase flicker noise. But beyond
that, we have no idea how defects causes flicker noise. So I
am not surprised he doesn't go into that.

Similarly, Rb vapor cells are not his business, oscillators and
filters are. He probably had just a project that was used in
an Rb standard, so it's understandable he didn't go into those
details either.

Overall the presentation was a nice overview of his works.

			Attila Kinali

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