Paul B. Webster VK2BZC wrote:
>
> James Henke wrote:
>
> > But don't forget that if you're pulsing the LEDs in a quadrature
> > encoder, you must sample the output fast enough to satisfy the Nyquist
> > criteria, in synchrony with the led pulsing.  What's the maximum RPM x
> > counts per revolution? Sample at LEAST that fast, and preferably much
> > faster.
>
>   Hey!  Do I gather he's being very clever here and multiplexing the
> quadrature encoder by pulsing the LEDs?  Cool idea!
>
>   Cheers,
>         Paul B.
Better sample twice as fast. As I remember it (too lazy too look it up)
Fs = 2x Fmax
, where Fs = sample frequency, and Fmax is maximum frequency to be
sampled.

Hans