That is not true.
- You could have two simultaneous false-pulses.
- You could have two false-pulses that happen in coordination:
- one high followed by the other high
- one low followed by the other high
- etc.
I am not so sure that this is such an infrequent thing. The processor operates at a 16 megahertz rate. That means there is the potential for 16X10^6 false positives/negatives every second. The probabilities don’t have to be very high for this to happen on a regular basis. It is not a question of -if- it happens, but how frequently.
Further, the external circumstances that cause false-positives and false-negatives happen very similarly for both encoder lines. In other words, both encoder wires are subject to the same EMF noise that causes voltage deviations. If there is a positive voltage deviation on one line, the other line is subject to the same environment, and likely experiences the same positive voltage deviation. So, if one encoder line experiences a false-positive pulse, it is very likely the other encoder line will, too, because they are run in parallel and receive the same ambient noise.
I agree with as a potential issue. However, if we appropriately size the capacitors, this won’t happen.
I like the idea of shielding the wires, and I think it is a very good step. However, capacitors cost something like $.01, which is a really cheap and easy modification. I would like to do both, because I see this as an unknown. I would really like to see some community members do some work to analyze this; both the effect of the capacitor and the shielded wire.