Patent ID: 7046177
Filing Date: 2006-05-16
Classification: G11B

Abstract:
1. A servo system for generating a normalized digital actuator-signal from a first and control signal (P) and a second control signal (Q), said servo system comprising a sigma delta modulator for generating a digital representation of a quotient (P−Q)/(P+Q) between a difference (P−Q) and a sum of the two control signals (P+Q), characterized in that the sigma-delta-modulator is an analog sigma-delta-modulator (M) having an analog low-pass filter (F), a quantizer (E) arranged for receiving an output signal of the analog low-pass filter, a multiplying DA-converter (W) for converting and multiplying an output signal of the quantizer by the sum (P+Q) of the first and second control signals and means for supplying the difference (P−Q) of the first and second control signals and the output signal of the multiplying DA-converter (W) to an input of the analog low-pass filter (F).