EP0601894A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Disc reading method and disc reading apparatus

Assignee: Panasonic Holdings Corp

•

Filing: 1993-12-13

•

Granted: —

•

Expires: 2013-12-13

📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A disc reproducing apparatus for reproducing data stored on plural disc surfaces at a constant linear density comprises: plural heads for reproducing the data on the plural disc surfaces at the same time respectively; a controller for controlling positions of the heads such that a total data rate of data reproduced form the plural heads is constant, each of the disc surfaces being divided into N circumference zones; N signal processing circuits, having N processing speeds corresponding to N data rates corresponding to the N circumference zones, for processing the reproduced data respectively; a switch for supplying the reproduced data to the N signal processing circuits such that data reproduced by each of the plural heads is supplied to either of the N signal processing circuits suitable for the data rate of the supplied data thereto; and a combining circuit for combining the processed data signals from the N signal processing circuits into a combined serial data signal of which data rate corresponds to the total of data rates. A disc reproducing method of reproducing data stored on a plurality of disc surfaces at a constant linear density using N signal processing circuits and the switch is also disclosed.

Inventors

👤 Shigeru Furumiya
👤 Yoshinari Takemura

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-09 00:36

CPC Classifications

G; G11; G11B; G11B20/00; G11B20/10; G11B20/12; G11B20/1217; G11B20/1258

Claims Analysis

Total Claims: 5

Claim 1

Independent Claim 248 words

A disc reading apparatus for reading data stored on a plurality of disc surfaces at a constant linear density comprising: (a) rotating means for rotating said disc surfaces at a constant rotational speed; (b) a plurality of heads for reading said data on said plurality of disc surfaces at the same time respectively; (c) position detection means for detecting positions of said plurality of heads to produce position signals; (d) position control means for controlling radial positions of said plurality of heads such that a total of data rates of data read by said plurality of heads in accordance with said position signals is constant, each of said disc surfaces being divided into N circumferential zones, wherein said N is a natural number; (e) N signal processing circuits for processing said read data respectively, said N signal processing circuits having N processing speeds corresponding to N data rates corresponding to said N circumferential zones; (f) switch means for supplying said read data to said N signal processing circuits in accordance with at least one said position signals such that data read by each of said plurality of heads is supplied to the one of said N signal processing circuits corresponding to the one of said N circumferential zones at which that head is located; and (g) combining means for combining said processed data signals from said N signal processing circuits into a combined serial data signal of which the data rate corresponds to said total of data rates.

Claim 2

Dependent Claim 32 words

A disc reading apparatus as claimed in claim 1, wherein each of said N signal processing circuits comprises a waveform equalisation circuit, having a pre-determined time constant, for waveform-equalizing said read data.

Claim 3

Dependent Claim 42 words

A disc reading apparatus as claimed in claim 1 or claim 2, wherein each of said N signal processing circuits comprises a clock signal producing circuit, having a pre-determined time constant, for producing a clock signal from said read data supplied thereto.

Claim 4

Dependent Claim 54 words

A disc reading apparatus as claimed in claim 1, 2 or 3 wherein said combining circuit comprises N memory circuits for storing said processed read data for producing N time-divided-and time-compressed serial data signals at each pre-determined interval, and for combining said N time-divided-and time-compressed serial data signals into said combined serial data signal.

Claim 5

Independent Claim 194 words

A method of reading data stored on a plurality of disc surfaces at a constant linear density, said plurality of disc surfaces being rotated at a constant rotational speed, comprising the steps of: (a) reading said data on said plurality of disc surfaces at the same time with a plurality of heads respectively; (b) detecting positions of said plurality of heads to produce position signals; (c) controlling positions of said plurality of heads such that a total of data rates of data read by said plurality of heads is constant, each of said disc surfaces being divided into N circumferential zones, said N data rates corresponding to said N circumferential zones wherein said N is a natural number; (d) supplying and processing said read data to N signal processing circuits in accordance with at least one of said position signals such that data read by each of said plurality of heads is supplied to the one of said N signal processing circuits corresponding to the one of said N circumferential zones at which that head is located; and (e) combining said processed data derived from said plurality of heads into serial data with time-compression.

References Cited (Backward Citations)

EP0273384A1 Cited

EP0316084A2 Cited

US5111345A Cited

EP0487296A2 Cited

EP0506447A1 Cited

USPTO Annuity & Maintenance Windows

Maintenance schedule is calculated for granted US utility patents.

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag

Select Category

Notes (Optional)