Servo system, apparatus comprising a servo system, sigma delta modulator, and integrated circuitcomprising a sigma delta modulator
AssigneeKoninklijke Philips Electronics N.V.
InventorsAlbert Immink, Johannes Aldegonda Theodora Van Den Homberg, Aalbert Stek
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Abstract
A servo system comprising an analog sigma delta modulator for generating a normalized digital error correction signal from first and second analog control signals. The sigma delta modulator comprises an analog low-pass filter, a quantizer delivering the digital error correction signal and a multiplying DA-converter in feedback arrangement between the output of the quantizer and the input of the low-pass filter for multiplying the feedback signals with the sum of the analog control signals.
Claims14
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).
A sigma delta modulator for generating a digital representation of a quotient (P−Q)/(P+Q) between a difference (P−Q) and a sum (P+Q) of a first control (P) and a second control signal (Q) signal, characterized in that the sigma-delta-modulator is an analog sigma-delta-modulator (M) having an analog low-pass filter (F), a quantizer (E) 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 with 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 of the multiplying DA-converter (W) to an input of the analog low-pass filter (F).
Dependencies are inferred from the claim text.