Reproducing apparatus reproducing data from a recording medium having a preformatted address area at a starting position of each sector

Claim 2

A reproducing apparatus of a recording medium having an address area preformatted at a starting position of each of a plurality of sectors, the apparatus comprising: pattern detection means for detecting a predetermined pattern of a data pulse train in said starting position of each sector; timing creation means for creating a reading timing, at which an address of a sector is to be read, according to the detection of said predetermined pattern of the data pulse train; and discrimination means for discriminating whether an address read from said recording medium based on said reading timing created by said timing creation means is correct or not; wherein said timing creation means creates reproducing timings for the sector of said address and an address reading timing for a next sector which follows said sector, based on a point in time when said address is read.

Claim 3

A reproducing apparatus according to claim 1, wherein said timing creation means includes a counter which counts a predetermined count while being reset by an output from said pattern detecting means, and gating means responsive to the output from said counter for generating a mask signal which inhibits the detection of said predetermined pattern for a predetermined period from the point in time when said predetermined pattern has been detected.

Claim 4

A reproducing apparatus according to claim 2, further comprising a selector for selecting an output from said pattern detection means and said discrimination means, and control means for controlling selection of said selector to select a predetermined number of successive outputs from said pattern detection means at an initial stage of beginning to detect start positions of successive sectors on said recording medium, and then to select successive outputs from said discrimination means.

Claim 5

A reproducing apparatus according to claim 3, wherein each sector includes at the starting position thereof first and second CRC codes respectively attached to two same addresses of said sector and wherein said discrimination means checks the first address on the basis of the first CRC code and then checks the second address on the basis of the second CRC code only when the check of said first address has resulted in failure.

Claim 6

A reproducing apparatus according to claim 4, wherein when said selector issues an output from said discrimination means which indicates said second address being successfully checked on the basis of said second CRC code, said counter is reset with a predetermined value which is equal to a value said counter would take at that time if said counter had been reset by detection of a successful check of said first address.

Claim 7

A reproducing apparatus according to claim 5, further comprising means responsive to an output of said counter to generate first and second gate signals which enable said discrimination means to check said first and second addresses respectively within predetermined periods within which respective successful checks of said first and second addresses are expected to occur.

Claim 8

A reproducing apparatus according to claim 5, wherein when the check of said second address results in failure on the basis of said second CRC code, said counter is reset with a predetermined value which is equal to a value said counter would take at that time if said counter had been reset by detection of a successful check of said first address.

Claim 9

A reproducing apparatus according to claim 7, wherein said control means causes said selector to select the output from said pattern detection means when unsuccessful detections of both of said first and second addresses have successively occurred a predetermined number of times.

Claim 10

A reproducing apparatus according to claim 1, further comprising: storing means for successively storing data indicating the point in time when said address has correctly been read; and difference calculating means for calculating a difference between said point in time for a previous sector and said point in time for a current sector, based on a content of said storing means; wherein said timing creation means generates said address reading timing for said next sector based on the calculated difference.

Claim 11

A reproducing apparatus according to claim 9, wherein said recording medium has first and second same addresses at the starting position of each of said sectors, and wherein said difference calculating means is capable of calculating an immediately previous inter-sector distance from the point in time when one of said first and second addresses in the previous sector was read and the point in time when one of said first and second addresses in the current sector has been read.

Claim 12

A reproducing apparatus according to claim 1, wherein each sector includes at the starting position thereof a CRC code attached to the address of said sector and said discrimination means discriminates whether said address is correct or not on the basis of said CRC code.

Claim 13

A reproducing apparatus according to claim 11, wherein said timing creation means includes a counter which counts a predetermined clock while being reset by an output from said pattern detection means, and further comprising means responsive to an output of said counter to generate a gate signal which enables said discrimination means to check said address within a predetermined period within which a successful check of said address is expected to occur.

Claim 14

A reproducing apparatus of a recording medium having an address area preformatted at a starting position of each of a plurality of sectors at which a VFO pattern and an address of the sector are recorded, said apparatus comprising: pattern detection means for detecting the VFO pattern in said starting position of each sector; and timing creation means for creating an address reading timing for a sector which follows a preceding sector whose VFO pattern point has been detected by said pattern detection means, based on a time point of detection of said VFO pattern of said preceding sector; said timing creation means creating an address reading timing for a sector which follows the sector whose address has been read, based on a time point when said address has been read, and also creating reproducing timings for a data area of the sector whose address has been read, based on a time point when said address has been read.

Claim 15

A reproducing apparatus of a recording medium having an address area preformatted at a starting position of each of a plurality of sectors at which a VFO pattern and an address of the sector are recorded, said apparatus comprising: pattern detection means for detecting the VFO pattern in said starting position of each sector; and timing creation means for creating an address reading timing for a sector which follows a preceding sector whose VFO pattern point has been detected by said pattern detection means, based on a time point of detection of said VFO pattern of said preceding sector; said timing creation means creating an address reading timing for a sector which follows the sector whose address has been read, based on a time point when said address has been read, and also creating reproducing timings for a data area of the sector whose address has been read, based on a time point when said address has been read.

Claim 16

A reproducing apparatus according to claim 13, wherein said timing creation means includes a counter which counts a predetermined clock while being reset by an output from said pattern detection means.

Claim 17

A reproducing apparatus according to claim 13, further comprising means for generating a mask signal which inhibits the detection of said VFO pattern by said VFO pattern detection means for a predetermined period from the time point when said VFO pattern has been detected.

Claim 18

A reproducing apparatus of a recording medium having an address area performatted at a starting position of each of a plurality of sectors at which an address of the sector and a CRC code corresponding to said address are recorded, said apparatus comprising: discrimination means for checking an address read from said address area of said recording medium on the basis of said CRC code corresponding to said address to determine whether said address has correctly been read; and timing creation means for creating an address reading timing for a sector which follows the sector whose address has been read, based on a time point when said address has correctly been read; said timing creation means creating reproducing timings for a data area of the sector whose address has correctly been read, based on a time point when said address has correctly been read.

Claim 19

A reproducing apparatus of a recording medium having an address area performatted at a starting position of each of a plurality of sectors at which an address of the sector and a CRC code corresponding to said address are recorded, said apparatus comprising: discrimination means for checking an address read from said address area of said recording medium on the basis of said CRC code corresponding to said address to determine whether said address has correctly been read; and timing creation means for creating an address reading timing for a sector which follows the sector whose address has been read, based on a time point when said address has correctly been read; said timing creation means creating reproducing timings for a data area of the sector whose address has correctly been read, based on a time point when said address has correctly been read.

Claim 20

A reproducing apparatus according to claim 16, wherein each sector includes at the starting position thereof first and second CRC codes respectively attached to two same addresses and wherein said discrimination means checks the first address on the basis of the first CRC code and then checks the second address on the basis of the second CRC code when the check of said first address has resulted in failure.

Claim 21

A reproducing apparatus according to claim 17, wherein said timing creation means includes a counter which counts a predetermined clock while being reset by an output from said discrimination means.

Claim 22

A reproducing apparatus according to claim 18, wherein when said discrimination means issues a signal indicative of said second address being successfully checked on the basis of said second CRC code, said counter is reset with a predetermined value which is equal to a value said counter would take at that time if said counter had been reset by detection of a successful check of said first address.

Claim 23

A reproducing apparatus according to claim 19, further comprising means responsive to an output of said counter to generate first and second gate signals which enable said discrimination means to check said first and second addresses respectively within predetermined periods within which respective successful checks of said first and second addresses are expected to occur.

Claim 24

A reproducing apparatus according to claim 19, wherein when the check of said second address results in failure on the basis of said second CRC code, said counter is reset with a predetermined value which is equal to a value said counter would take at that time if said counter had been reset by detection of a successful check of said first address.

Claim 25

A reproducing apparatus for reproducing data from a disc medium having thereon a plurality of tracks each being divided into a plurality of sectors, each of said sectors having an identification (ID) area and a data area in which an address unique to said sector and user data are respectively recorded, said ID area of each sector being preformatted with a VFO pattern, which is used to generate a synchronization clock for recording to and reproducing from said sector, and a CRC code which is used to check the address of said sector whether said address has correctly been read, said apparatus comprising: reproducing means for reproducing data on a sector of said disc medium; CRC operation means for performing a CRC operation to an address recorded in the ID area of said sector which is contained in said data reproduced by said reproducing means; counting means for performing a counting operation according to a result of said CRC operation; and starting-position indication means for generating a reference signal which provides a reference of a starting position of a given sector when said CRC operation of a sector preceding said given sector has successfully resulted and said CRC operation of said given sector successfully results by a time at which a count of said counting means reaches a predetermined value.

Claim 26

A reproducing apparatus for reproducing data from a disc medium having thereon a plurality of tracks each being divided into a plurality of sectors, each of said sectors having an identification (ID) area and a data area in which an address unique to said sector and user data are respectively recorded, said ID area of each sector being preformatted with a VFO pattern, which is used to generate a synchronization clock for recording to and reproducing from said sector, and a CRC code which is used to check the address of said sector whether said address has correctly been read, said apparatus comprising: reproducing means for reproducing data on a sector of said disc medium; CRC operation means for performing a CRC operation to an address recorded in the ID area of said sector which is contained in said data reproduced by said reproducing means; counting means for performing a counting operation according to a result of said CRC operation; and starting-position indication means for generating a reference signal which provides a reference of a starting position of a given sector when said CRC operation of a sector preceding said given sector has successfully resulted and said CRC operation of said given sector successfully results by a time at which a count of said counting means reaches a predetermined value.

Claim 27

A reproducing apparatus according to claim 22, wherein said ID area in each sector of said disc medium includes a plurality of addresses unique to said sector along with a plurality of corresponding CRC codes, and said starting-position indication means treats said CRC operations with respect to said plurality of addresses of a sector as being successful if at least one of said CRC operations successfully results.

Claim 28

A reproducing apparatus according to claim 22, wherein said counting means includes a counter which counts a predetermined clock while being reset by an output from said CRC operation means which indicates a successful result of said CRC operation.