Patent EP0123946A1 successfully refreshed from Google Patents.
EP0123946A1
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EP
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Reproducing rate control apparatus for information recording disc
Assignee: Hitachi Ltd
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Filing: 1984-04-03
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Granted: —
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Expires: 2004-04-03
Abstract
Abstract The angular speed of a DAD-disk (1) is controlled to maintain a constant linear velocity. To save time in the search mode, the angular speed is changed to a calculated new value before the head (32) has reached the desired track. There are also means (30, 31) to measure the speed in order to ascertain the velocity at which the disk was recorded. This value is used when computing the angular speed at the desired track.
Inventors
- 👤 Yoshimi Iso
- 👤 Harushige Hitachi-Hachimanyama Nakagaki
- 👤 Masafumi Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 21:26
CPC Classifications
G; G11; G11B; G11B19/00; G11B19/20; G11B19/24; G11B19/28; G11B20/00; G11B20/10; G11B20/10527; G11B21/00; G11B21/02; G11B21/08; G11B21/081; G11B21/083; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/32
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
133 words
A reproducing rate control apparatus for an information recording disc (1) in which pieces of information and absolute times for respective information pieces representative of the reproduction time measured from the innermost circumference of the information recording disc are recorded on said disc at a constant linear velocity, said apparatus comprising: means (23, 24) for predicting a revolution number of said disc at a command position; means (10, 19, 21, 23, 24) for controlling rotation of a motor (2) for rotating said disc so that said disc rotates at a predicted revolution number; and means (33, 34, 35) for moving an information reader (32) adapted to read the information recorded on said disc to the command position when the revolution number controlling is effected or after the revolution number controlling has been completed.
Claim 2
Dependent Claim
133 words
A reproducing rate control apparatus for an information recording disc (1) in which pieces of information and absolute times for respective information pieces representative of the reproduction time measured from the innermost circumference of the information recording disc are recorded on said disc at a constant linear velocity, said apparatus comprising: means (23, 24) for predicting a revolution number of said disc at a command position; means (10, 19, 21, 23, 24) for controlling rotation of a motor (2) for rotating said disc so that said disc rotates at a predicted revolution number; and means (33, 34, 35) for moving an information reader (32) adapted to read the information recorded on said disc to the command position when the revolution number controlling is effected or after the revolution number controlling has been completed.
Claim 3
Dependent Claim
67 words
A reproducing rate control apparatus for an information recording disc according to Claim 1 wherein said revolution number prediction at said command position is carried out in accordance with an absolute time-revolution number correspondence table recorded on a storage unit, and said revolution number controlling is carried out by selecting one of a plurality of voltage sources (V to V x ) provided for various revolution numbers.
Claim 4
Dependent Claim
64 words
A reproducing rate control apparatus for an information recording disc according to Claim 1 wherein said revolution number prediction at said command position is carried out in accordance with an absolute time-revolution number correspondence table recorded on a storage unit, and said revolution number controlling is carried out by using a PWM wave generator (26) and a low-pass filter (19) connected in series therewith.
Claim 5
Dependent Claim
62 words
A reproducing rate control apparatus for an information recording disc according to Claim 1 further comprising a disc drive motor revolution number detector (30), whereby a revolution number detected by said disc drive motor revolution number detector is compared with said predicted revolution number to effect the revolution number controlling so that the former revolution number coincides with the latter revolution number.
Claim 6
Dependent Claim
43 words
A reproducing rate control apparatus for an information recording disc according to Claim 4 wherein said motor rotation controlling means (24) comprises a ramp function generator (Fig. 13) including an integration amplifier (107), and two constant current sources (101, 102) of different polarities.
Claim 7
Dependent Claim
87 words
A reproducing rate control apparatus for an information recording disc according to Claim 4, further comprising a position detector (31) for said information reader (32), whereby a disc recording linear velocity is measured from an output of said information reader position detector and an output of said disc drive motor revolution number detector, and the revolution number prediction at the command position is effected by calculating an absolute time-revolution number correspondence corresponding to the linear velocity or selecting one of calculation results recorded on a storage unit.
Claim 8
Dependent Claim
87 words
A reproducing rate control apparatus for an information recording disc according to Claim 5, further comprising a position detector (31) for said information reader (32), whereby a disc recording linear velocity is measured from an output of said information reader position detector and an output of said disc drive motor revolution number detector, and the revolution number prediction at the command position is effected by calculating an absolute time-revolution number correspondence corresponding to the linear velocity or selecting one of calculation results recorded on a storage unit.
References Cited (Backward Citations)
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