[time-nuts] Re: GPSDO Control loop autotuning

[Matthias Welwarsky]

On Dienstag, 12. April 2022 00:52:42 CEST Magnus Danielson via time-nuts 
wrote:

> A trivial state-space Kalman would have phase and frequency. Assuming
> you can estimate the phase and frequency noise of both the incoming
> signal and the steered oscillator, it's a trivial exercise. It's
> recommended to befriend oneself with Kalman filters as a student
> exercise. It can do fairly well in various applications.

I'm wondering, can the frequency really be part of the state? It is not a 
property we can measure independently, we can only derive it from the TIC 
measurements. There is the EFC value of course, but that doesn't directly 
correspond with the output frequency...