# US 5,353,271 A · Method and apparatus for recording or reproducing information on or from recording medium

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- Number: US 5,353,271 A
- Document ID: US5353271A
- Status: Granted
- Kind: A
- Application number: 07/930,778
- Filed: 1992-08-17
- Granted: 1994-10-04
- Earliest claimed: 1991-08-29
- Assignees: Ricoh Company, Ltd.
- Inventors: Michiharu Abe
- Web page: https://patentgrep.com/patent/US5353271A

## CPC

- G11B 20/10222: {clock-related aspects, e.g. phase or frequency adjustment or bit synchronisation (dedicated sync patterns in the modulation code G11B20/1403)}
- G11B 7/005: Reproducing (G11B7/0065 takes precedence)
- G11B 20/10009: {Improvement or modification of read or write signals}
- G11B 20/1403: {characterised by the use of two levels}
- H04L 7/0337: {Selecting between two or more discretely delayed clocks or selecting between two or more discretely delayed received code signals}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method for recording or reproducing information on or from a recording medium, the method capable of reproducing serial data on the basis of signals derived on each of front edges or each of rear edges of a plurality of pieces of recorded information on the recording medium, includes the steps of reproducing bit-synchronization signals corresponding to each ones of the front and rear edges from signals derived on the front and rear edges alternately provided in the recorded information, the bit-synchronization signals having individual phases but the same frequency as each other, switching the bit-synchronization signal for each of the front edges into the other bit-synchronization signal for each of the rear edges or vice versa after a predetermined time each time the bit-synchronization signal is detected, synthesizing the bit-synchronization signals so that a phase of the synthesized bit-synchronization signal constantly matches to phases of the front and rear edges to be detected, and sequentially reproducing the serial data from signals derived on a lot of the front and rear edges by using the synthesized bit-synchronization signal.

## Claims

### Claim 1

A method for recording or reproducing information on or from a recording medium, the method capable of reproducing serial data on the basis of signals derived on each of front edges and each of rear edges of a plurality of pieces of recorded information on said recording medium, comprising the steps of:
reproducing first and second bit-synchronization signals respectively corresponding to said front edges and said rear edges from signals derived on said front edges and said rear edges alternately provided in said recorded information, said first and second bit-synchronization signals having individual phases but the same frequency as each other;
alternatively switching the first and second bit-synchronization signals after a predetermined time every time the first or second bit-synchronization signal is detected;
synthesizing the first and second bit-synchronization signals in such a manner that a phase of the synthesized bit-synchronization signal constantly corresponds to phases of said front edges and said rear edges to be detected; and
sequentially reproducing the serial data directly from signals derived on a lot of said front edges and said rear edges by using the synthesized bit-synchronization signal.

### Claim 2 (depends on 1)

A method according to claim 1, wherein said predetermined time is (n+0.5) times a period of the first or second bit-synchronization signal, said n being an integer equal to or more than 0.

### Claim 3

An apparatus for recording or reproducing information on or from a recording medium, said apparatus capable of reproducing serial data on the basis of signals derived on each of front edges and each of rear edges of a plurality of pieces of recorded information on said recording medium, comprising:
a bit-synchronization signal reproducing circuit for reproducing first and second bit-synchronization signals respectively corresponding to said front edges and said rear edges from signals derived on said front edges and said rear edges alternately provided in said recorded information, said first and second bit-synchronization signals having individual phases but the same frequency as each other;
a bit-synchronization signal synthesizing circuit for alternatively switching the first and second bit-synchronization signals after a predetermined time every time the first or second bit-synchronization signal is detected, and for synthesizing the first and second bit-synchronization signals in such a manner that a phase of the synthesized bit-synchronization signal constantly corresponds to phases of said front edges and said rear edges to be detected;
a delay circuit for generating a delay signal as a gate signal on each switching by said synthesizing circuit; and
a data reproducing circuit for sequentially reproducing the serial data directly from signals derived on a lot of said front edges and said rear edges by using the synthesized bit-synchronization signal.