Siemens Probability Meter

[EEVblog]

Anyone have any idea what this does?

https://twitter.com/spotlynx/status/1551277849268682752

[Ed.Kloonk]

Looks suspiciously like a sophisticated bullshit meter to me.

Plug the news into it. Off the scale, I'm sure.

[Someone]

Looks like an input and an output on the front panel?

[xrunner]

Does it have something to do with phases of two inputs being measured?

[EEVblog]

Someone on Twitter said this:

It's a Vibration analysis meter, but ask a German schooled engineer who was around in the early 70s, I can only go by the google searched translations of German texts.
SIEMENS-ZEITSCHRIFT, Band 48, Nr. 9, 1974; P. Ringlage: "Schwingungsanalyse mit dem Probabilitymeter" *

Could be a coherence meter?

[tszaboo]

I'm going to guess, that it's some sort of statistical meter, where you input pulses on the two coax, and it gives you some statistical probability of the process. But the minimum frequency indicated on the front makes me wonder, that it's probably not that.

[HighVoltage]

I would think it measures the phase shift between two signals.

Hook it up to a function generator with 2 outputs and play with the phase angle to see how this instrument reacts.

[georgd]

I bet it's a window comparator. Channels have separated level controls and common delta.

https://en.wikipedia.org/wiki/Window_detector

[switchabl]

@georgd Yes, I believe so. It will show the duty cycle of the comparator output, i.e. the percentage of time spent within the window. So if you e.g. fix ΔU_REF and vary U_REF (with suitable step-size) you will get a histogram. That would be U-mode, I guess it will also have an A-B correlation mode.

The output will be on the back. Likely just the "probabilty" as a 0-1V voltage signal or something. Potentially with a switchable low-pass filter (the output knob has a "DC" position and another one that is not visible).

Btw has anyone else noticed that the plastic knob for the U_B reference voltage is not actually missing? It has just been "misplaced". Where's Wally?

[AVGresponding]

@georgd Yes, I believe so. It will show the duty cycle of the comparator output, i.e. the percentage of time spent within the window. So if you e.g. fix ΔU_REF and vary U_REF (with suitable step-size) you will get a histogram. That would be U-mode, I guess it will also have an A-B correlation mode.

The output will be on the back. Likely just the "probabilty" as a 0-1V voltage signal or something. Potentially with a switchable low-pass filter (the output knob has a "DC" position and another one that is not visible).

Btw has anyone else noticed that the plastic knob for the U_B reference voltage is not actually missing? It has just been "misplaced". Where's Wally?

Hiding the evidence that someone has overloaded it!   

[Xandinator]

I second the vibration analysis approach. In contrast to a scope this will also show nice readings for incommensurable cycles/nonperiodic incidents, e.g. when dealing with a lot of nonlinear stuff. Like fluid dynamics feedback on electromechanical components...