deskthority

I notice that the patent for the mid-size (second generation) ITW magnetic valve switch notes that the magnetic valve version (the other being mechanical) is analogue:

https://www.google.com/patents/US4227163

So, are all magnetic valve switches analogue?

Their definitions (distinctions?) seem counter-intuitive to what, I would say, is common usage today.

"operated either as an analog magnetic type of contactless keyswitch or as a mechanical type of keyswitch"

My take would be that most of us look at a pure "on/off" situation as being inherently "digital" regardless of the apparatus.

At least from my understanding, I'd say it's mostly On/Off.

In theory, if you could ramp up/down the magnetic field as you pressed the slider in a similar range to the magnetic field generated by the pulse, you could measure the output current (or voltage).
But this is pretty tricky (calibration nightmare) to do even now, let alone in 1979.

So I guess I can safely ignore mentions of "analog" in that patent then.

Regardless of whatever aspect is "continuously variable" the on/off clickover is all that really matters here.

https://www.merriam-webster.com/dictionary/analog

The signal could be analogue, but it would not be useful as an analogue signal if it isn't (nearly) linear or if it can't be consistently measured over significant key travel.

I remember from a Topre patent that the linearity was one of its key points - showing that traditional capacitative key switches are not.

Edit: Grammar.

From what I understood it's analog transferred to digital: https://en.wikipedia.org/wiki/Schmitt_trigger

The impression that I get is that laptop trackpads were always multi-touch capable, but since they were only targeted at moving a pointer, no-one considered the idea of handling multiple fingers at once.

What's not clear to me here, is whether the analogue nature of these switches is in any way useful. That is, did it simply not occur anyone to do what people are doing with analogue switches now, or is it too non-linear or otherwise too limited to be used in the manner of a proper analogue switch?

The patent contrasts "mechanical" with "analog", and in addition to the technical aspect, I'm wondering what their definition of "mechanical" is, and what the scope of that definition means.