[time-nuts] Re: Hybrid analog digital dual stage DMTD based on nanoVNA HW. First actual measurement results

[Erik Kaashoek]

Hi Magnus,

After making some improvements as shown in the block diagram [1] the 
performance has improved .
When measuring two 10Mhz signals (no need for sharp edges, sine wave is 
sufficient) either zero or 0.01 Hz apart the phase difference measures 
as shown in [2]
Calculating the linear residue of the unwrapped phase [3] shows phase 
measurement resolution of +/- 2e-12 seconds and maximum pulling of +/- 
1e-11 seconds
When increasing the tau the phase resolution does improves a lot but the 
pulling stay's the same.
For my testing purposes this level of resolution and accuracy is great.
Erik.

[1] http://athome.kaashoek.com/time-nuts/DMTD/Block_diagram.PNG
[2] http://athome.kaashoek.com/time-nuts/DMTD/Phase_difference.png
[3] http://athome.kaashoek.com/time-nuts/DMTD/Phase_difference_residue.png

On 30-9-2022 0:22, Magnus Danielson via time-nuts wrote:
> It would be interesting to see just how far one could get the 
> affordable nanoVNA setup to run.