Peter C. Wallace wrote: > Certainly at high speed the interpolation is not of much use, but the > interpolator will of course also go bad at 0 speed. > No, the analog values from the encoder disc should be perfectly accurate at 0 speed. It is just analog sin/cos interpolation of the optical output from the disc. > We've considered using such and interpolator with our embedded motion > controller to avoid the (expensive if embedded) divide used for velocity > estimation. The interpolator is just a second order DPLL, fairly easy to > build > into the encoder logic, and has the advantage that the velocity falls out > directly from the first accumulator. > If you are trying to interpolate an already-digital signal, then what you say is true. But, analog interpolation works at zero speed, and can improve positional resolution as well as velocity.
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