Matsushita Electric Industrial Co., Ltd.

Kabushiki Kaisha Toshiba

Pioneer Electronic Corporation

Hitachi, Ltd.

Panasonic Corporation

Toshiyuki Shimada

Koichi Hirayama

Tadashi Kojima

Takeshi Nakajima

Akira Kurahashi

Ryusuke Horibe

Shin-ichi Tanaka

Shinichi Tanaka

Takao Arai

Toshifumi Takeuchi

Yoshiaki Moriyama

Hisashi Yamada

Fumihiko Yokogawa

Noboru Kikuchi

Kazuhiro Aoki

Hiromichi Ishibashi

Teruyuki Takizawa

Hiroyuki Miyachi

Satoshi Kondo

Takashi Ishida

Mamoru Shoji

Mitsurou Moriya

Shunji Ohara

Yoshikazu Goto

Masahiro Honjo

Yoshiyuki Ishizawa

Hironori Deguchi

Yasuaki Edahiro

Masaharu Imura

Masao Kitagawa

Hiromiti Ishibashi

Yoshiaki Pioneer Electronic Corp Moriyama

Fumihiko Pioneer Electronic Corp Yokogawa

In carrying out PWM-recording on optical disks, RESYNC BYTES including a bit compensation part, RESYNC detection part, and bit synchronization part are periodically inserted in the recorded data code stream. After encoding and at the time of decoding, RESYNC BYTES are detected by detection of the RESYNC detection part. The decoder is initialized by detecting the position of the bit synchronization part, and decoding is performed satisfactorily free from error. With this configuration, even for synchronization bytes having a comparatively long portion of consecutive code values, bit resynchronization is enabled free from mis-detection caused by peak shift. Even with the recording and reproducing characteristics with an un-symmetrical unerased area of the mark and space parts, the RESYNC detection part is fixed to either mark or space and RESYNC BYTES with little influence on an unerased area can be realized.

Optical recording disk capable of resynchronization in digital encoding and decoding

A transmitting method of digital data whereby information data can be reproduced at a high precision. In order to retain digital data in sectors comprising a plurality of sync frames and sequentially transmit, the sync frame is comprised of the sync signal and the run length limited code which satisfies the limitations of the minimum run length and the maximum run length, and the sync signal includes the sync pattern constituted by a bit pattern of a run length that is longer than the maximum run length by onlyT and addition bit patterns which are arranged before and after the bit pattern and each of which has a urn length that is longer than the minimum run length. The sync signal includes a specific code which indicates a position in the sector and which enables the DC control to be performed.

Digital data transmitting method

An image processing apparatus comprises a noise detection means for performing noise detection on an input image; a noise removal means for removing noise from a predetermined region of the input image, on the basis of the result of the noise detection; a counting means for obtaining the ratio of an area targeted for noise removal to the predetermined region of the input image; a statistics calculation means for obtaining the statistics on the ratios obtained by the counting means over a predetermined period of time; an image generation means for generating an image indicating the statistics; and an image composition means for superimposing the image generated by the image generation means on the image outputted from the noise removal means to generate a composite image for display. Therefore, the viewer can easily know how much noise is removed from the predetermined region of the input image, for every predetermined period of time.

Image processing method and image processing apparatus

A transmitting method of digital data whereby information data can be reproduced at a high precision. In order to retain digital data in sectors comprising a plurality of sync frames and sequentially transmit, the sync frame is comprised of the sync signal and the run length limited code which satisfies the limitations of the minimum run length and the maximum run length, and the sync signal includes the sync pattern constituted by a bit pattern of a run length that is longer than the maximum run length by only 3T and addition bit patterns which are arranged before and after the bit pattern and each of which has a run length that is longer than the minimum run length. The sync signal includes a specific code which indicates a position in the sector and which enables the DC control to be performed.

A digital modulation apparatus applies a method for converting data words to runlength-limited code words using plural conversion tables. The data words are converted to code words that significantly suppress the low frequency component of the final nonreturn-to-zero inverted signal. This digital modulation apparatus includes ROM tables for storing plural conversion tables containing the runlength-limited code words corresponding to the data words; end-runlength memories and evaluators for determining whether the runlength-limit constraints are satisfied in the interconnection between two consecutive code words when the data words to be converted are supplied; and a DSV controller for storing each of the code words that can be selected from two conversion tables to buffer memories when the runlength-limit constraints are satisfied, and selecting the code words wit the greatest effect suppressing the low frequency component in the obtained signal when the code words are NRZI converted.

Digital modulation apparatus, a digital modulation method, and a

A data transmission apparatus for transmitting an original data has a converter for converting the original data to sequential data codes. The data code is formed by a combination of HIGH level binary codes and LOW level binary codes. The maximum length of a continuous binary codes of one level, such as HIGH level, in the data codes is limited to T.sub.max, e.g., to 14T, in which T is a unit length representing one binary code, and the minimum length of a continuous binary codes of one level, such as HIGH level, in the data codes is limited to T.sub.min, e.g., 3T. A generator generates a synchronization code. The synchronization code is formed by a combination of HIGH and LOW level binary codes. The synchronization code comprises an identifier having a continuous binary codes of one level, such as HIGH level, with a predetermined length 16T which is 2T greater than T.sub.max. An inserter inserts the synchronization code intermittently in the sequential data codes.

Recording medium data transmission method and apparatus and data

An optical disk and optical disk apparatus used for accurately reproducing and recording information regardless of the physical distortions of disks and the electrical distortions of a tracking system. This is achieved in the present invention by providing an optical disk apparatus which takes into account the physical fluctuations, such as radial tilt and tangential tilt, and the electrical fluctuations, such as focus errors and tracking errors, and makes appropriate adjustments in the optical disk apparatus accordingly. These adjustments are made based upon relationships existing between a jittering amount of the reproduced signals and the above-mentioned fluctuations. Specifically, the present invention generates a predetermined pattern of marks which, when recorded, are arranged such that a signal reproduced from the predetermined pattern of marks is caused to jitter. Depending on the specific pattern of marks generated, the reproduced signal experiences an amount of jittering that is optimal so as to allow the present invention to make appropriate adjustments.

Optical disk and optical disk apparatus having a predetermined pattern

A digital video disk stores data codes and multifunctional synchronization codes in a data structure. The synchronization codes contain type information code identifying whether the synchronization code is located in a code sequence at the beginning of the data block, the beginning of a data block sector other than the first sector in the data block, the beginning of a line, or the middle of a line. The type information is expressed by two alternative patterns, type information code 1 and type information code 2, expressing the same information and differing in the number of is in the 5-bit sequence, i.e., an odd or even number of 1s. Which one of the two type information code pattern is used is selected according to the DSV so as to minimize bias in the dc component of the frame following the synchronization code.

Recording medium, recording method and apparatus, and reproduction

An optical disk drive for reading information recorded on a recording surface of an optical disk medium using an optical head to generate a read-out signal, comprises focus position control means for controlling a focal point of a light beam emitted from the optical head so that it is positioned on a focus position that is set as a position in the vicinity of the recording surface of the optical disk medium; equalizing means for performing waveform equalization using a set equalization quantity, to the read-out signal generated by the optical head, and outputting an equalization signal; jitter measuring means for measuring a jitter of the equalization signal output from the equalizing means; and optimum value searching means for searching for a focus position and an equalization quantity, at which the jitter is minimized. In this optical disk drive, for both the focus position and the equalization quantity, the jitter minimized point can be searched accurately.

Optical disk drive equipped with waveform equalizer and focus adjustment

A phase error between an information signal including a reference signal that can be detected asynchronously and a synchronized signal that is synchronously produced from the information signal is detected, and a signal in response to an absolute value of the phase error is produced. Further, a defect detecting signal is produced in response to the absolute value of the phase error. Therefore, whether a pulse signal exceeding a maximum value of the pulse width of the information signal, that is, a pulse signal exceeding the pulse width of the reference signal, is detected or not, it is possible to detect that the signal reproduction enters a defect region immediately after the entry. Accordingly, a defect with noise or a track jumping can be detected rapidly. Furthermore, an information transition interval of the information signal is measured for a prescribed period of time, and the defect detecting signal is terminated in response to a measured value of a time length of the reference signal that is detected in the prescribed period of time, in other words, the passing of the signal reproduction through the defect region is detected with reference to the synchronization of the reference signal. Therefore, pseudo locking of a PLL is avoided when it is operated again, and the PLL can be accurately re-locked.

Optical disk device

The information to be recorded is divided into 8-bit long data words. Each data word is then converted to 14-bit long code word. The code words are sequentially connected with a one-bit merging bit inserted between the code words to define a code bit sequence. The run-length of 0s in the code bit sequence is limited to be between 2 and 11. The one-bit merging bit normally takes a bit value of 0, but is changed to 1 when any one of the T.sub.min control or T.sub.max control is applied so as to accomplish the run-length limitation. The T.sub.min control is applied when the adjacent bits on both sides of the merging bit are 1s. The T.sub.max control is applied when trailing P bits of a code word preceding the merging bit and leading Q bits of a code word following the merging bit are all 0s, provided that P+Q.gtoreq.11, and in this case, at least either one of the P bits and Q bits has a bit sequence of (00000), and the bit sequence (00000) is changed to (00100).

Single merging bit DC-suppressed run length limited coding

Source data each consisting of m-bits can be converted into conversion codes each consisting of n (&gt;m) bits with ease, and reverse conversion thereof can be performed with ease. The code conversion and the reverse conversion can be characterized in terms of a series of tables. The current input source data and the next input source data are respectively taken in by registers. Whether or not the run length at a connecting portion between consecutive source data satisfies conditions is determined by a control unit, and a table to be used is selected to finally obtain a conversion code.

Code conversion and demodulation apparatus, a method thereof, and a

A data detection apparatus retrieved binary data modulated in conformity with the (d, k) constraint from an analog signal includes a timing extracting unit for generating a timing signal representing the timing at which the analog signal crosses the threshold value, a clock generating unit for generating a clock signal having a cycle corresponding to one bit of the binary data from the timing signal, a timing position detector for detecting the position in the cycle of the timing, and an error correcting unit for correcting an error in the binary data in accordance with the detected position.

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Kobe, Japan

Toshiyuki Shimada