Closed-loop scaling in fixed-point digital control

In fixed-point implementation of digital controllers, the effects of quantization can be reduced by proper scaling of the controller parameters. Commonly, controllers are scaled using l/sub 1/ norm based calculations, i.e., determining the worst case impulse response of the controller. This is only possible, however, if the controller is asymptotically stable. If this is not the case, a solution is to calculate the scaling transformation on the basis of the closed-loop impulse responses. From the experience with actual implementation on a compact disc system, frequency weighting reflecting the disturbance spectrum has to be applied as well to obtain good experimental results.<
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