SIGNAL PROCESSING DEVICE AND ROTATION ANGLE DETECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a signal processing device such as a Hall electromotive force signal detection device, which does not lose accuracy of offset cancellation when performing following steps; modulating a Hall electromotive force signal detected from a Hall element by synchronizing a direction of a bias current supplied to the Hall element with a two-phase clock signal and sequentially and alternately switching them; performing ΔΣ modulation by a ΔΣ modulator after performing modulation-demodulation processing which synchronizes the modulated Hall electromotive force signal with the clock signal and demodulates it; performing offset cancellation processing which performs frequency separation of an offset component to remove it from the ΔΣ-modulated signal; and performing gain adjustment based on a gain adjustment signal adjusting a duty ratio in repeating an integration operation by an integrator of the ΔΣ modulator.

SOLUTION: A signal processing device comprises a gain adjustment signal generator 145 generating a pulse signal which performs gain adjustment once for every half cycle period adjacent to a clock signal which is sent by a clock signal generator.

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