Re: Quadrature Counting

[Jon Elson <elson-at-pico-systems.com>]

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>On 12/21/02 1:43 AM, "Adam Hunt" <adam.r.hunt-at-gmx.net> wrote:
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>>I was wondering about the logic used to count a quadrature signal
>>(encoder).  It seems that I was told one time that such a signal is 2 bit
>>gray code.  I would guess that a simple state machine would be used.
>>    
>>
Yes, that is exactly right.  A state machine with 4 states does it.  You 
can add a little more fancy
stuff to filter noisy signals from the encoder.  A pair of signals in 
quadrature is identical to
a 2-bit Gray code.

Jon