Sanyo Electric Co., Ltd.

Nec Corporation

Kabushiki Kaisha Toshiba

Toshiba Corporation

Masato Fuma

Miyuki Okamoto

Akihito Ogawa

Yutaka Kashihara

Yutaka Yamanaka

Tsuyoshi Yamamoto

Tatsunori Ide

Nagatoshi Sugihara

Hideki Takahashi

Shigeru Shimonou

Fumiaki Nagao

Takao Inoue

Katsuki Hattori

Masaru Matsui

Yutaka Tamura

Kazuo Watabe

Shuichi Ohkubo

Hiroshi Watanabe

Morio Nakatani

Shinichiro Tomisawa

Satoshi Kanai

Takanori Kishida

Katsumi Hattori

An optical disc has a read-only system lead-in area and a recordable data area. Disc boundary information representing a boundary in a radial direction of an area on which capability of recording at a predetermined recording speed is guaranteed is recorded on the system lead-in area while being related to each tuple speed. An optical disc device, upon user's instruction of tuple-speed recording, compares the boundary information related to the instructed tuple speed with a present recording position, performs recording at the instructed tuple speed if the present recording position is on the outside of the boundary, and performs recording at a tuple speed lower than the instructed tuple speed if the present recording position is on the inside of the boundary.

Optical disc for tuple-speed recording and optical disc device for tuple-speed recording

In an optical disk recording method of recording data onto a recordable optical disk which includes a data zone where data is recorded and a management data zone where management data indicating the recorded part of the data zone is recorded, an extended management data zone in which the management data is to be recorded is set in the data zone in response to an extension instruction.

Optical disk, optical disk recording method, and optical disk recording apparatus

Data is recorded on an optical disc using a combination of a user data area where user data is recorded, a control data area for reproduction provided on an inner radius side of the user data area, and an outer guard zone provided on an outer radius side of the user data area as a unit of one recording operation. In this configuration, a track pitch TP of the optical disc is greater than or equal to 0.3 &#x3bc;m and smaller than or equal to 0.4 &#x3bc;m, and the width of the outer guard zone along a radius direction of the optical disc is greater than or equal to a value of (100&#xd7;TP) and smaller than or equal to a value of (125&#xd7;TP).

Optical disc recording method and apparatus

An error correction circuit capable of detecting burst errors included in a data signal with reliability. The error correction circuit comprises a reading unit, a first estimation unit, a second estimation unit, and a correction unit. The reading unit reads the data signal. The first estimation unit estimates error locations based on BIS code included in the data signal, and stores the locations into an error location storing unit. The second estimation unit estimates error locations based on characteristics of bit strings adjoining the BIS code, and stores the locations into the error location storing unit. The correction unit identifies erasure locations based on the error locations stored in the error location storing unit, and performs erasure correction on the erasure locations identified. Since the error locations are estimated based on the BIS code and the characteristics of the bit strings adjoining the BIS code as well, it is possible to detect burst errors without fail.

Method of detecting error location, and error detection circuit, error correction circuit, and reproducing apparatus using the method

An object of the present invention is to provide an optical recording/reproducing apparatus capable of improving medium usability through a laser power adjusting process while keeping compatibility with a read only type medium. The optical recording/reproducing apparatus adjusts laser power using a PCA till the PCA is used up. After the PCA is used up, an additional area is reserved at the outermost circumference position, thereafter when the additional area is used up, a new additional area is reserved at an inner circumference side of the used up additional area to adjust laser power. The additional area is reserved at an outer circumference than a lead-out area, and therefore format compatibility with a read only type optical disc can be maintained. The additional area is reserved only when the PCA is used up, thus capacity compatibility with a read only type optical disc can be maintained while laser power is adjusted with only the PCA.

Optical recording/reproducing apparatus

A method according to the present invention generates weight data for each audio band and assigns a number of bits to each band according to the weight data. The method then calculates a total of the numbers of bits of one block and compares the total with an upper limit and with a lower limit of a compression target value. Based on the comparison result, the method increases or decreases the value of the weight data to update it. The method reassigns a number of bits based on the updated weight data.

Method and apparatus for subband coding, allocating available frame bits based on changable subband weights

User data transmitted from the host side is first stored in write cache regions of an SDRAM on the basis of an error correction process. When executing an ECC&bull;EDC encode process of adding redundancy data such as an error correction code to the stored user data on the basis of the error correction processing, an encode region of SDRAM is used. The data subjected to the ECC&bull;EDC encode process is sequentially read out from encode region to be modulated and then written onto a disk.

Write cache circuit, recording apparatus with write cache circuit, and write cache method

A write address counter counts a write clock WCK and determines output as a write address, while read address counter counts a read clock RCK and determines output as a read address. The position of LSB in both the counters is shifted by the same number of bits at predetermined intervals, and the position of LSB of the read address counter before shifting is corresponded with the shifted position of the write address counter after shifting. Both the counters count and determine their outputs as write and read addresses. Thus, memory capacity can be reduced, and data can be written and read with different write and read orders.

Address generating circuit

Logarithm of data x being input is taken to calculate a decibel value y. The input value x is separated into mantissa value a and exponent value b by a separator or on the basis of an expression x&equals;a&middot;2 . Logarithmic value 10&middot;log a corresponding to the mantissa value a is read from ROM. The exponent value b is multiplied with a constant 10&middot;log 2 for logarithm of 2 by a multiplier. A logarithmic value of the value a read from the ROM is added to b&middot;10&middot;log 2 output from the multiplier by an adder to obtain the decibel value y. Thus, a simple circuit can compute the decibel value at a high speed.

Logarithmic value calculation circuit

There is disclosed a discrete cosine transform circuit for use in a voice recording/reproducing device to solve problems that RAM in which data is stored is frequently accessed and that the power consumption is large. In discrete cosine transform, an algorithm can be constituted to include four or less items of operand data in one operation equation. Correspondingly, four registers,-,to,-,are arranged on the output side of RAM,. The discrete cosine transform includes a predetermined regularity. For example, a plurality of operation equations using the same operand data are included in the processing. By continuously processing all of the operation equations, the data read into the registers,-,to,-,can be reused without being overwritten in another processing, so that accesses to RAM,can be suppressed.

Discrete cosine transform circuit and operation method thereof

The present invention relates to an error correcting and detecting apparatus that executes a decode process at high speed. The error correcting and detecting apparatus receives digital data including an error correction code and an error detection code and performs error correction and error detection on the digital data. In one embodiment, the apparatus includes: an input interface for receiving the digital data from a recording medium and writing the digital data into a memory device; an error correction decoder for receiving the digital data from the memory device and performing error correction on the digital data in accordance with error correction codes; an error detection decoder for receiving the digital data from the memory device and performing error detection on the digital data in accordance with error detection codes; and an output interface for reading digital data from the memory device and outputting the read digital data, the read digital data having undergone the error correction and error detection. The error correction by the error correction decoder and the error detection by the error detection decoder are performed in parallel.

Decoder for executing error correction and error detection in parallel

A synchronous circuit which detects a detection synchronizing signal generated from a reproduction signal in a detecting window having a prescribed time width, and in a detecting window having a prescribed time width, and generates a frame synchronizing signal. The synchronous circuit includes a counter for counting how many times detection synchronizing signals are not consecutively detected, and a detecting window width determining unit for increasing the time width of the detecting window if, as a result of comparison between a value counted by the counter and a prescribed value set in advance, the counted value reaches the prescribed value.

Synchronous circuit and optical disk reproduction device capable of

A read only disc according to the present invention has a spiral recording track formed on the surface thereof. The recording track includes a plurality of record unit blocks formed continuously by an optical recording method, wherein each record unit block includes a dubbing permitted area and a dubbing inhibited area. Digital audio information having compressed data is recorded in the dubbing permitted area. On the other hand, display data associated with the digital audio information is recorded in the dubbing inhibited area. Thus, digital dubbing of digital audio information can be carried out and dubbing of display data is prevented to ensure dominance of the read only disc as a master software.

Read only digital audio information recording medium and digital dubbing

An audio data dubbing system includes a reproduction side device and a recording side device. The reproduction side device reproduces intermittently from a reproduction side disc compressed audio data on the basis of a predetermined reproducing unit, which is first stored in a reproduction side memory and read out continuously therefrom to be provided as compressed audio data for recording. Recording side device first stores in a recording side memory compressed audio data for recording provided from the reproduction side device and reads out the same therefrom intermittently in a predetermined recording unit to be recorded on a recording side disc. The recording side device suspends the reproduction operation of compressed audio data from the reproduction side disc in the reproduction side device when the data amount in the recording side memory is increased to exceed a first reference value. The reproduction side device suspends the recording operation of the compressed audio data for recording to the recording side disc in the recording side device when the data amount in the reproduction side memory is decreased to become lower than a second reference value.

Audio data recording/reproduction device having digital high speed

A disc recorder containing a compressed data memory for storing compressed audio data to be recorded to a disc or reproduced from a disc. When a reduction pause state is set during reproduction operation, reading out of data from a compressed data memory is limited. Therefore, discontinuity of reproduced audio at the time of pause cancellation is prevented. When a recording pause state is set during recording operation, the compressed data memory is made empty. Therefore, discontinuity of the recording audio is also prevented at the time of pause cancellation.

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Ichinomiya, Japan

Masato Fuma