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

[Bob kb8tq]

Hi

When you blow cold air over this or that, you likely create a temperature 
gradient. Sensitivities of various parts are actually higher to gradients
than to temperature offsets. It’s typically a stress / strain relation that relaxes
out in steady state. 

In addition to ( as noted above ) suspecting everything in the circuit. You 
also have to suspect the measurement technique……

Bob

> On Oct 23, 2022, at 12:05 PM, Erik Kaashoek via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> During the testing of a DMTD there appears to be a "large" sensitivity to temperature variations.
> Opening a door in the room with the DMTD causes changes in the phase difference in the order of 1 ps
> Blowing cold air over the encased DMTD causes phase variations up to 10 ps.
> The analog part of the DMTD exists out of some coax, SMA connectors, active mixers and ADC's. The rest is digital and not expected to be temperature sensitive.
> Its not clear yet which parts are causing the temperature sensitivity
> As the design is symmetric (both inputs have the same components almost the same layout) I did not expect this.
> Are these levels to be expected?
> Erik.
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