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公开(公告)号：US3609562A
公开(公告)日：1971-09-28
申请号：US3609562D
申请日：1970-07-17
Applicant: IBM
Inventor： GRANATA PETER J , MUELLER FRANCIS E
CPC classification number: G11B20/16 , G11B5/59616
Abstract: This invention relates to a demodulator used in a servopositioning system which is maintained in synchronization both during the track-seeking mode and the fine-positioning mode of operation of the servosystem. The demodulator monitors signals received from the servoed medium and obtains from this signal, positioning information between the servoed means and the servoing apparatus, while obtaining synchronization information from the same received signals. The demodulator is comprised of a positive level detector, a negative level detector, a synchronizable free-running multivibrator, delayed single shots, gates, a positive peak detector and a negative peak detector. A means for including a noise rejection means into the demodulator is also shown.
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公开(公告)号：CA1165824A
公开(公告)日：1984-04-17
申请号：CA377183
申请日：1981-05-08
Applicant: IBM
Inventor： ALLEN JAY W , GRANATA PETER J
Abstract: A sine wave oscillating circuit arrangement useful in generating an electromagnetic field, for example, comprises a resonant circuit including an inductor through which the current is tightly controlled and a capacitor connected in parallel, to which dc pulses are applied at a repetition rate equal to the resonant frequency. The current flowing in the inductor is sensed in phase detector and amplitude detectors. The results of these evaluations are applied to cascaded pulse position and pulse width and/or amplitude modulators. A current switching driver circuit driven by pulses from the modulator is connected to the resonant circuits for modifying the dc pulses applied for maintaining the sine wave current in the inductor at the proper amplitude and phase relationship and energy content inversely as the potential across the sampling resistor in the resonant circuit. The energy dissipated in damping the resonant circuit in one cycle of operation is replaced in the next cycle. SA979045
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