The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 13, 1993
Filed:
Jun. 28, 1991
Randall C Bauck, Boulder, CO (US);
Scott E Chase, Longmont, CO (US);
James W Hargarten, Lafayette, CO (US);
Maxtor Corporation, San Jose, CA (US);
Abstract
An automatic digital control system includes a proportional integral derivative (PID) compensator in which the digital differentiator portion, with its associated zero-order hold, is implemented according to an algorithm that reduces phase loss as a function of frequency. The digital differentiator is based only on a present error sample so that the output of the digital differentiator (with its ZOH) is made to resemble an amplitude-balanced step function (i.e., a doublet) during a given sample period T. The step transition occurs at one-half of the period (i.e., at T/2). Another embodiment further reduces phase loss by confining the output waveform of the differentiator to some fraction of the total sampling period. During the remaining portion of the sampling period the digital differentiator (again, with its associated ZOH) is forced to some desired reference level.