That's a brilliant idea, using hysteresis so that
the negative pulse is detected too. Just keeping on
with the "minimum parts" idea I wonder if this could
be implemented by adding a capacitor to the single
transistor circuit, so the + pulse charges it and
the - pulse discharges it. This might give good
fractional response but will probably generate the
occasional false pulse as the cap discharges after
the thing stops turning.
-Roman


Peter L. Peres wrote:
>
> Roman, I did not consider that you would have to resolve single detents.
> You are right about there being one detent where there are two (-) pulses.
> I propose the following two solutions:
>
> 1. Use a Schmitt trigger on each input. The Schmitts will 'integrate' the
> pularised pulses and produce normal quardature outputs (sin,cos, indigital
> form). The Shmitt can be implemented with the opamps I suggested.
>
> Try these values: 10K/10K and decouple to gnd with 1uF for reference,
> connect motor common here.
>
> Each trigger has - input to referencee, 1K from (+) input to motor phase,
> 1M positive feedback from out to (+) input and 4k7 pullup on the output.
> The 1M may have to be reduced to up to 100k to improve noise immunity.
>
> 2. Build two fliflops using IIL technology with a few discrete
> transistors, each controlled by a motor phase. IIL has low logic levels
> and it should work with the motor voltages properly.

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