Disc recording/reproducing system
First Claim
1. A disc recording/reproducing system wherein record tracks on a disc are divided in multiple zones in a radial direction of the disc and wherein the disc is rotated and driven at a constant angular velocity so that a recording/reproducing data rate changes stepwise for every zone on the disc or rotated and driven such that an angular velocity changes stepwise for every zone on the disc, the disc recording/reproducing system comprising:
- a data rate control area provided at a boundary between a first zone and a second zone on said disc or controlling said recording/reproduced data rate;
a control area detecting means for detecting said data rate control area when data extends between said first and said second zones; and
a frequency control means for controlling a frequency of one of a recording/reproducing data extracting PLL and a recording reference frequency generating PLL when said data rate control area is detected, wherein said frequency control means comprises;
a reference clock;
a comparator that compares an output of said data extracting PLL and an output of said reference clock;
an up/down counter which is incremented or decremented based on an output of said comparator thereby outputting a count value; and
means for modifying said count value into a pulse width modulated signal and providing said pulse width modulated signal as an input to said data extracting PLL to control a frequency of said output of said data extracting PLL.
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Accused Products
Abstract
A disc recording/reproducing system where recording/reproduced data rates change stepwise when spiral record tracks on a disc medium are divided in multiple zones in the radial direction and the disc is rotated and driven at a constant angular velocity or when a rotating and driving angular velocity changes stepwise for every zone, the disc recording/reproducing system is provided with a data rate control area provided at the boundary between a first and second zones on the disc medium for controlling the recording/reproduced data rate, a control area detecting device for detecting the data rate control area when continuously recording/reproducing data extends over the first and second zones and a frequency controller means for controlling the frequency of a recording/reproducing data extracting PLL or a recording reference frequency generating PLL when the data rate control area is detected.
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Citations
5 Claims
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1. A disc recording/reproducing system wherein record tracks on a disc are divided in multiple zones in a radial direction of the disc and wherein the disc is rotated and driven at a constant angular velocity so that a recording/reproducing data rate changes stepwise for every zone on the disc or rotated and driven such that an angular velocity changes stepwise for every zone on the disc, the disc recording/reproducing system comprising:
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a data rate control area provided at a boundary between a first zone and a second zone on said disc or controlling said recording/reproduced data rate; a control area detecting means for detecting said data rate control area when data extends between said first and said second zones; and a frequency control means for controlling a frequency of one of a recording/reproducing data extracting PLL and a recording reference frequency generating PLL when said data rate control area is detected, wherein said frequency control means comprises; a reference clock; a comparator that compares an output of said data extracting PLL and an output of said reference clock; an up/down counter which is incremented or decremented based on an output of said comparator thereby outputting a count value; and means for modifying said count value into a pulse width modulated signal and providing said pulse width modulated signal as an input to said data extracting PLL to control a frequency of said output of said data extracting PLL. - View Dependent Claims (2, 3, 4, 5)
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Specification
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- Resources
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Current AssigneeKabushiki Kaisha Toshiba (Toshiba Corporation)
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Original AssigneeKabushiki Kaisha Toshiba (Toshiba Corporation)
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InventorsIshizawa, Yoshiyuki
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Primary Examiner(s)Hindi, Nabil Z.
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Application NumberUS08/233,878Time in Patent Office805 DaysField of Search369/32, 369/50, 369/48, 369/54, 369/58, 369/124, 369/44.26, 360/51, 360/49, 360/77.08, 360/78.14US Class Current369/47.3CPC Class CodesG11B 20/1258 where blocks are arranged w...G11B 20/1403 characterised by the use of...G11B 7/00745 Sectoring or header formats...
