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:
May. 20, 1997
Filed:
Jan. 10, 1995
Johannes L Bakx, Eindhoven, NL;
Other;
Abstract
An optical writing and/or reading device. A radiation source (10) generates a radiation beam (11). This radiation beam (11) is directed by an optical system onto a servotrack (4) of a rotating record carrier (1). The beam reflected via the record carrier is passed on to a push-pull detector (12). The servotrack has a periodical radial wobble whose frequency is modulated in accordance with a position-information signal. A signal-regaining circuit (17) regains the position-information signal from the push-pull signal. A balancing circuit (41, 42; 50, 51) adjusts a weighting the ratio between the detection signals which contribute to the difference signal. The DC component in the adapted push-pull signal is derived by means of a low-pass filter (44). In dependence upon the determined DC component, a circuit (45) sets the weighting ratio to a value at which the determined DC component is substantially zero.