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

[glen english LIST]

I have used the switched capacitor type, with direct control over the 
switching caps .

We were able to high speed dither the switch settings to get 1/2 and 1/4 
and 1/8 steps of the minimum capacitor switch step. This way, we got 
high control resolution.

BUT- this only works for requirements that are tolerant of the switching 
spurs, phase mod etc.

The medium term frequency stability was important - over seconds -Â  not 
very short term of milli seconds.

If I need very low noise I use a varactor (capacitance) or YIG style 
control , analog LPF and single bit sigma delta converter in the FPGAÂ  
(free in FPGA fabric) , and a then fractional dither to get my sub-bit  
resolution.

-glen

On 19/02/2022 11:24 am, Magnus Danielson via time-nuts wrote:
> Hi Erik,
>
> I only saw that thread later, and I will have to return to that as I 
> have a little more energy.
>
> I'm trying to get you up to speed with