摘要:
To enable a physically rewritable disc to be appropriately used as a write-once type.When the rewritable disc is used in rewritable application, the position where writing of a predetermined data unit (for example, an ECC block) in data is started is set to a first position with respect to a reference position to record or play back the data. In contrast, when the rewritable disc is used in write-once application, the position where writing of the predetermined data unit in the data is started is set to a second position different from first position to record or play back the data. The position where writing of the data is started in the rewritable application is shifted from the position where writing of the data is started in the write-once application to disable rewriting of the data recorded on a rewritable recording medium when the rewritable recording medium for the write-once application is loaded in a recording-playback apparatus that does not assume the use of the rewritable recording medium in the write-once application.
摘要:
A recording medium as a physically rewritable disk is appropriately used as a write-once type. In order to use the rewritable media in write-once applications, the recording medium in the data structure thereof includes, in a second data unit (an ECC block of 64 Kbytes), flag information WF1-WF4 indicating whether a first data unit (2 Kbytes) is stored. More specifically, whether a plurality of first data units (a sector handled by a host) has been recorded in the second data unit (a recording unit sector on the recording medium) is directly indicated. When an access request is issued in emulation in a disk drive device, the flag information is referenced, and the disk drive device determines whether one of writing or reading of the first data unit as a target responsive to a command is enabled.
摘要:
To enable a physically rewritable disc to be appropriately used as a write-once type. When the rewritable disc is used in rewritable application, the position where writing of a predetermined data unit (for example, an ECC block) in data is started is set to a first position with respect to a reference position to record or play back the data. In contrast, when the rewritable disc is used in write-once application, the position where writing of the predetermined data unit in the data is started is set to a second position different from first position to record or play back the data. The position where writing of the data is started in the rewritable application is shifted from the position where writing of the data is started in the write-once application to disable rewriting of the data recorded on a rewritable recording medium when the rewritable recording medium for the write-once application is loaded in a recording-playback apparatus that does not assume the use of the rewritable recording medium in the write-once application.
摘要:
An optical disk apparatus for a phase-change optical disk detects the boundary between a first region and a second region prior to detecting a synchronization mark. The synchronization mark is detected in accordance with the position of the detected boundary between the first region and the second region. User data is read from a data region in accordance with the detected synchronization mark.
摘要:
An ACS of a Viterbi decoder generates status data that an SMU represents a status transition corresponding to the maximum likelihood status transition selected corresponding to each read clock pulse. A merge block generates decoded data corresponding to status data. A timing generator generates timings of a leading edge and a trailing edge of a reproduced RF signal corresponding to status data. A PEC generates a phase error signal PE corresponding to a reproduced signal value sampled at these the timings (namely, sampling values of an A/D converter). With the phase error signal PE, a VCO is controlled. The memory length of the SMU that generates the timings is smaller than the memory length for a decoding process. One of the memory lengths can be selected depending on whether data is reproduced from a header area or a data area.
摘要:
In a Viterbi decoder, an SMU is used instead of a PMU. The SMU has four status memories that process a status data value composed of a plurality of bits that represent a status at a time. The status memories generate a sequence of four status data values. A merge block generates decoded data corresponding to the four status data values, detects mismatches of four status data values, and generates a mismatch detection signal NM. The number of mismatches is counted corresponding to the mismatch detecting signal NM. The quality of decoded data and reproduced signal are evaluated corresponding to the count value.
摘要:
A structure for detecting a phase error for causing a PLL of an information reproducing apparatus to be locked and for selecting Viterbi determination mode, MSB determination mode (for obtaining a phase error detection timing corresponding to MSB of output data of an A/D converter disposed on the preceding stage of a Viterbi decoder) is disclosed. One of the three modes is selected corresponding to the state of the PLL. A Viterbi timing generating circuit, an MSB timing generating circuit, and a frequency lock mode timing generating circuit are provided. Phase error detection timings generated by the three circuits are selectively supplied to a phase error detecting circuit by a sampling pulse selecting switch. The selected phase error detection timing is switched between the acquisition mode and the tracking mode.
摘要:
In a magneto-optic disc apparatus corresponding to six-value four-status Viterbi decoding method, an RAA has 12 registers so as to separately adapt amplitude reference values for an address portion and amplitude reference values for a data portion on a magneto-optic disc. Normally, stored values of the registers at the time a reproducing operation has been just completed are used for initial values for an adapting process in the next reproducing operation. On the other hand, when data cannot be correctly reproduced and thereby a read-retry operation or the like is preformed, predetermined values that are stored in 12 registers in the RAA are used as initial values. In this case, the adapting process for amplitude reference values is not performed.
摘要:
An A/D converter (30) samples an analog signal synchronously with a sampling clock from a VCO (70). These sampled values are stored in a shift register (410). A code judging section (420) detects the positive/negative sign pattern (time-series code pattern) of the sampled values held in storage elements (S0 to S5) of the shift register (410) and stores the sampled values in predetermined register (431 to 434) according to the detected sign pattern. According to this, a calculating section (430) determines the phase difference between the analog signal and the sampling clock. The phase difference is fed to a VCO (70) through a D/A converter (50) and a loop filter (60).
摘要:
In a magneto-optic disc apparatus corresponding to six-value four-status Viterbi decoding method, an RAA has 12 registers so as to separately adapt amplitude reference values for an address portion and amplitude reference values for a data portion on a magneto-optic disc. Normally, stored values of the registers at the time a reproducing operation has been just completed are used for initial values for an adapting process in the next reproducing operation. On the other hand, when data cannot be correctly reproduced and thereby a read-retry operation or the like is preformed, predetermined values that are stored in 12 registers in the RAA are used as initial values. In this case, the adapting process for amplitude reference values is not performed.