[time-nuts] Re: What phase variations to expect in a DMTD due to temperature fluctuations?

[Attila Kinali]

On Wed, 16 Nov 2022 07:41:30 +0100
Erik Kaashoek via time-nuts <time-nuts at lists.febo.com> wrote:

> Its rather compute intensive and I'm not sure what the offset has to be 
> to become invisible but could you imagine this could work in a rather 
> limited HW?

Before you go into your digital down mixer or CIC, you will have some form
of anti-aliasing filter. This filter's bandwidth is your first indication
how far you should be away. Later filters in the signal chain then filter
out the remaining components.

If you want to minimize the influence of the probe signal, you can,
and IMHO should, add a notch filter into the signal path. That should
give you some 80-100dB of additional damping and remove the probe signal
for all intents and purposes.

It is still a good idea to check for some kind of modulation in the
(processed) output at the difference frequency and its multiples.

BTW: I recommend having a look at [1], which is a very hands on book
on signal processing. It gives examples of what kind of structures to
use for different signal processing tasks and discusses their advantages
and disadvantages.

			Attila Kinali

[1] "Understanding Digital Signal Processing",
by Richard Lyons, 3rd edition, 2011

-- 
In science if you know what you are doing you should not be doing it.
In engineering if you do not know what you are doing you should not be doing it.
        -- Richard W. Hamming, The Art of Doing Science and Engineering