[time-nuts] Re: 10 MHz TCXO periodically jumping 20 mHz up and down

[Attila Kinali]

On Fri, 18 Feb 2022 11:56:02 +0100
Magnus Danielson via time-nuts <time-nuts at lists.febo.com> wrote:

> I think you have yourself a digital TCXO controller. Those use a 
> tempsensor, use the reading to calculate the compensation and the use a 
> normal varactor control to steer the frequency.

Quick side note: On modern, cheap TCXO systems, expecially those
for RTCs, frequency control is being done by a bank of switched
capacitors. This is mostly because capacitors can be implemented
in a standard digital CMOS process (or analog CMOS process).

A varactor, on the other hand, would need a special doping
profile (high-doping concentration with an abrupt transition).
Or in other words an additional half a dozen processing steps
which cost a lot of time and money... especially for a single
diode on a chip.

			Attila Kinali

-- 
The driving force behind research is the question: "Why?"
There are things we don't understand and things we always 
wonder about. And that's why we do research.
		-- Kobayashi Makoto