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:
Aug. 16, 1988
Filed:
Dec. 17, 1986
Hiroshi Sasaki, Hitachi, JP;
Tomio Chiba, Katsuta, JP;
Mitsuyasu Kido, Hitachi, JP;
Yoshio Sato, Hitachi, JP;
Atsumi Watanabe, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A disc is provided with the equal-interval pits along tracks, at which digital signals are recorded bit by bit. Such a disc is rotated at the constant angular velocity. A signal processing apparatus according to the present invention detects the linear velocity of the track which is at present followed by a pickup. The filtering of a source signal to be recorded and the analog-to-digital conversion of the filtered signal, in the signal processing for recording, are controlled and timed in accordance with the detected linear velocity. Further, the digital-to-analog conversion of a signal read out from the disc and the filtering of the converted signal, in the signal processing for reproducing, are also timed and controlled in response to the detected linear velocity. Thereby, a disc memory device having the large storage capacity and suited for the random access memory can be realized.