MDCP: Patent Abstact US05142521: Recording/reproducing device

US05142521 Recording/reproducing device

Assignee Sharp Corporation

Assign./Filed Aug. 25, 1992/ May 25, 1990

Inventors Terashima; Shigeo, Deguchi; Toshihisa, Kojima; Kunio, Maeda; Shigemi

Summary Recordable CD which allows data at various sampling rates to be recorded.

Abstract A recording/reproducing device performs the recording/reproduction on a recording medium having an information recording area and a table of contents area. The recording medium is provided with guiding grooves that snake in cycles corresponding to values of absolute addresses. The device divides the information recording area into a plurality of domains. Each domain corresponds to a single sampling frequency with respect to the information being recorded. An electromagnet and an optical head record information in the domain that corresponds to its sampling frequency and records additional information concerning the division in the table of contents. A spindle motor drives the disk which is adjusted such that the velocity of the disk is changed for each domain during recording and reproduction. A demodulator obtains the absolute addresses through demodulation by comparing frequencies determined from the snaking cycles of the guiding grooves with a reference frequency. An operational circuit converts the demodulated absolute addresses in accordance with the velocity of the disk into corrected absolute addresses that represented the period of time which has elapsed since the starting time. As a result, the burden imposed on the spindle motor is relieved, the demodulation of the absolute addresses may be executed accurately even when the rotational speed of the disk varies, and the time elapsed since the start of the recording/reproduction may be determined.

US05142521	Recording/reproducing device
Assignee	Sharp Corporation
Assign./Filed	Aug. 25, 1992/ May 25, 1990
Inventors	Terashima; Shigeo, Deguchi; Toshihisa, Kojima; Kunio, Maeda; Shigemi
Summary	Recordable CD which allows data at various sampling rates to be recorded.
Abstract	A recording/reproducing device performs the recording/reproduction on a recording medium having an information recording area and a table of contents area. The recording medium is provided with guiding grooves that snake in cycles corresponding to values of absolute addresses. The device divides the information recording area into a plurality of domains. Each domain corresponds to a single sampling frequency with respect to the information being recorded. An electromagnet and an optical head record information in the domain that corresponds to its sampling frequency and records additional information concerning the division in the table of contents. A spindle motor drives the disk which is adjusted such that the velocity of the disk is changed for each domain during recording and reproduction. A demodulator obtains the absolute addresses through demodulation by comparing frequencies determined from the snaking cycles of the guiding grooves with a reference frequency. An operational circuit converts the demodulated absolute addresses in accordance with the velocity of the disk into corrected absolute addresses that represented the period of time which has elapsed since the starting time. As a result, the burden imposed on the spindle motor is relieved, the demodulation of the absolute addresses may be executed accurately even when the rotational speed of the disk varies, and the time elapsed since the start of the recording/reproduction may be determined.