Mitsubishi Denki Kabushiki Kaisha

Fumio Matsuda

Minoru Ozaki

Kazuya Sato

Kaoru Kawasaki

Kazuhiko Nakane

Masaharu Ogawa

Hajime Nakajima

Kyosuke Yoshimoto

Kunimaro Tanaka

Koichi Takeuchi

Kouichi Yamada

Hiroyuki Kumazawa

Masayoshi Shimamoto

Mitsuo Maeda

Motomu Yoshimura

Yoshiki Nakajima

Tooru Inoue

An input image is digitized. The corresponding digital video data are reproduced while they are successively recorded on a magnetic video device. A successive recording control unit manages at which position of a successive recording area the digital data are to be successively recorded to realize the endless recording in a limitative recording area. When an event occurs, the control unit manages to exclude the recorded image before and after the corresponding event image from the endless recording area so that the event image can be held as an event recording image. Since the monitored image can be reproduced while it is recorded, it can be reproduced timely retroactively, and the image before and after an event occurs can also be reproduced instantaneously. Further, since the recording is continued while the image is reproduced, event images corresponding to plural events can be left.

Video recording device for retroactively reproducing a video image of an

An apparatus in accordance with the present invention sequentially fixes the wavelength of a light beam irradiated from a light source whose oscillation wavelength sequentially varies to a plurality of different wavelengths to a recording medium to required wavelengths each capable of forming a hole at absorption spectrum of the recording medium, synchronizes timing of change of the wavelength of the light source with timing of recording or regenerating each bit of information, records the optical hole formed in a manner that each bit of information corresponds to the wavelength varying in sequence, and detects the formed hole to regenerate information. Furthermore, the holes formed by the same wavelength are recorded at the positions separated by a distance capable of avoiding interference, while the holes formed by different wavelengths in correspondence to each bit of information are recorded at nearly the same position while that position is slightly displaced at a time, and thereby information is multiple-recorded with high density.

Frequency selective optical data record/regenerate apparatus

In an information storage apparatus having an error-correcting code, wherein digital information and check symbols are stored in groups of codewords which are divided into blocks of equal size and a synchronization field for data synchronization is added to each block, a detector detects errors in consecutive synchronization fields when the digital information is read, and a flag-setting circuit sets dropout flags when a signal from the detector indicates an error in consecutive synchronization fields. The flags are set from the last synchronization field that is correctly detected before the error up to the first synchronization field that is correctly detected after the error. In decoding the codewords, the errors in them are corrected with reference to the dropout flags.

Information storage apparatus

A recording format on a recording medium comprises a data portion (4) in which a data train should be recorded. The data portion (4) comprises a user data portion (44 and 47), a check data portion (45) and resynchronizing pattern portions (46). The data train is divided into m or 4 code words, each code word being n=148 bytes. The resynchronizing pattern portions (46) are added to the data train for every m.times.3=12 bytes of data to be recorded, and serves to recover data synchronization in the event that data synchronization is missed. Each code word having a check data portion (45) is capable of correcting errors of T bytes, and errors generated in each code word by missing of data synchronization can be corrected.

Data recording method with improved synchronization recovery

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Tokyo, Japan

Fumio Matsuda