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140 条记录 (耗时 0.022 秒)

    Error correction method and system
    31.
    发明公开
    Error correction method and system 失效
    错误校正方法和系统

    公开(公告)号：EP0129849A3

    公开(公告)日：1986-04-09

    申请号：EP84107110

    申请日：1984-06-20

    申请人： HITACHI, LTD.

    发明人： Okamoto, Hiroo ,  Kobayashi, Masaharu Hitachi-Hachimanyama ,  Nishimura, Keizo ,  Noguchi, Takaharu ,  Arai, Takao ,  Shibuya, Toshifumi

    IPC分类号： G11B05/09

    CPC分类号： G11B20/1809

    摘要： This invention relates to an error correction upon reproduction of digital signals. The error correction is performed by decoding code words such as cross-interleaved Reed Solomon codes, in which first code blocks are formed by a plurality of information words which are in the first arrangement state and a plurality of first check words which are produced by codes associated with the plurality of information words with a Hamming distance of d,, and second code blocks are formed by a plurality of information words and a plurality of first check words which are in the second arrangement state and which consist of the said plurality of information words and the said plurality of first check words which are respectively included in the different first code blocks, and by a plurality of second check words which are produced by codes associated with the plurality of information words and the plurality of first check words with a Hamming distance of d 2 . At the first decoding stage, at least errors are detected and at the same time the flags indicative of the decoding states are i added with respect to the second code blocks. At the second decoding stage, in accordance with the contents of the flags and on the basis of a combination of p 2 and q selected from their combinations satisfying 2p 2 +q≤d 1 -1, errors are detected and errors of p 2 words are corrected and erasures of q words to which the flags were added are corrected with respect to the first code blocks.

    Rotary head type digital information signal recording and reproducing apparatus and tracking control method therein
    32.
    发明公开
    Rotary head type digital information signal recording and reproducing apparatus and tracking control method therein 失效
    与数字信息信号和Nachführregelungsverfahren旋转头记录和重放设备。

    公开(公告)号：EP0137346A2

    公开(公告)日：1985-04-17

    申请号：EP84110989.5

    申请日：1984-09-14

    申请人： HITACHI, LTD.

    发明人： Noguchi, Takaharu ,  Yamazaki, Shigeru ,  Arai, Takao

    IPC分类号： G11B15/473 ,  G11B20/10 ,  G11B20/18

    CPC分类号： G11B15/4678 ,  G11B5/0086 ,  G11B5/00878 ,  G11B5/09 ,  G11B20/10527 ,  G11B20/1809

    摘要： In a rotary head type digital information signal recording and reproducing apparatus having plural rotary heads mounted on a rotary drum so as to be capable of recording and reproducing signals on parallel, oblique tracks on a magnetic tape (10), a tracking signal is recorded on at least one portion (50) of each track which is not overlapped with a portion (49) of each track where a digital information signal is recorded to avoid interference between the tracking signal and information signal. The tape travel speed and the rotary drum rotation speed are changed depending upon the transmission rate for a digital information signal to be recorded and reproduced to make the wavelength of a recorded signal frequency constant irrespective of the signal transmission rate. Tracking control is enhanced without increasing the error rate.

    Method and system for transsion/reception of encrypted digital signal
    35.
    发明公开
    Method and system for transsion/reception of encrypted digital signal 失效
    用于发送/接收加密的数字信号的方法和装置。

    公开(公告)号：EP0675655A3

    公开(公告)日：1997-09-24

    申请号：EP95104480.9

    申请日：1995-03-27

    申请人： HITACHI, LTD.

    发明人： Amada, Nobutaka ,  Yamazaki, Shigeru ,  Noguchi, Takaharu ,  Nishijima,Hideo ,  Ono, Hiroaki ,  Okamoto, Hiroo ,  Owashi, Hitoaki ,  Arai, Takao ,  Hatanaka, Yuji ,  Saito, Seiichi

    IPC分类号： H04N7/52

    CPC分类号： H04N7/52 ,  H04N5/9261 ,  H04N5/937

    摘要： A digital information signal transmitting/receiving method and system having a transmitter (100) for transmitting an encrypted digital information signal and a plurality of receivers (200) for receiving the encrypted digital information signal from the transmitter (100). The transmitter (100) simultaneously distributes a plurality of identification codes associated with the receivers (200) ahead of the digital information signal. Then, the digital information signal is distributed to the receivers. The receivers (200) detect particular, or their own, identification codes from the plurality of identification signals assigned to the receivers (200). The received encrypted digital information signal is decrypted into the original information on the basis of the particular identification codes associated with the corresponding receivers or the recorders (300). Either the receivers (200) or the recorders (300) generate an information request signal. The transmitter (100) is responsive to this information request signal to add to the digital information signal identification signals for identifying the receivers (200) or the recorders (300) which generated the information request signal. The recorders (300) control the received information signal to be recorded in response to the identification signals received by the receivers (200).

    Rotary head type magnetic recording and reproducing apparatus
    36.
    发明公开
    Rotary head type magnetic recording and reproducing apparatus 失效
    装置，用于记录和用旋转磁头鼓再现。

    公开(公告)号：EP0658052A3

    公开(公告)日：1995-10-18

    申请号：EP94119441.7

    申请日：1994-12-08

    申请人： HITACHI, LTD.

    发明人： Suzuki, Hideaki ,  Yoshida, Susumu ,  Amada, Nobutaka ,  Takeuchi, Toshifumi ,  Arai, Takao

    IPC分类号： H04N5/926 ,  H04N5/91

    CPC分类号： H04N5/78263 ,  H04N5/78213 ,  H04N5/783 ,  H04N5/913 ,  H04N9/7904 ,  H04N9/7973 ,  H04N9/802 ,  H04N9/8042 ,  H04N9/83 ,  H04N9/87 ,  H04N2005/91364

    摘要： A rotary head type magnetic recording and reproducing apparatus for recording and reproducing an analog wide-band video signal, audio signal and compressed digital signal on the same recording medium. The modulated analog wide-band video signal or the narrow-band-converted compressed digital signal is recorded on two video tracks adjacent to each other on a magnetic tape (301) by magnetic heads (301a, 301b and 302a, 302b) on a rotary drum (300). In another arrangement in which the audio signals multiplexed in frequency are recorded on the audio track adjacent to the video tracks on the magnetic tape (310) by the magnetic heads (303a, 303b) and the decision circuit (264), by utilizing the signal reproduced from the audio track, determines whether the signal recorded on the video tracks is analog or digital, the input analog wide-band video signal is divided into signals of two channels by the recording-system analog signal processing circuit (57), those signals are recorded on the magnetic tape (60) in multi-track recording by a pair of magnetic heads (62a, 62b) and another pair of magnetic heads (62, 62d), the input audio signals are modulated by the FM modulator (15) and the QPSK modulator (16), and recorded in a deep-layer portion of another track between the video tracks. A compressed digital digital signal received by the antenna (1) is added with error correction codes by the recording-system digital signal processing circuit (5), and is modulated by the 16QAM modulator (6) so that the spectral components of the compressed digital signal does not enter the audio signal frequency band, and is recorded on said audio track superposed but in a deeper-layer portion of the tape by yet another pair of magnetic heads (64a, 64b).

    Apparatus for the recording and/or the reproducing of video signals
    37.
    发明公开
    Apparatus for the recording and/or the reproducing of video signals 失效
    用于记录和/或再现视频信号的设备

    公开(公告)号：EP0581227A3

    公开(公告)日：1994-03-09

    申请号：EP93111922.6

    申请日：1993-07-26

    申请人： HITACHI, LTD.

    发明人： Okamoto, Hiroo, Higashitotsuka ,  Oku, Masuo, Kamakura ,  Noguchi, Takaharu, Totsuka ,  Arai, Takao

    IPC分类号： H04N5/92 ,  H04N5/91 ,  G11B20/00

    CPC分类号： G11B20/00086 ,  H04N5/913 ,  H04N5/9206 ,  H04N2005/91314 ,  H04N2005/91321 ,  H04N2005/91328

    摘要： In a reproducing apparatus, a generator circuit (9) for adding copy information during the vertical blanking period of a reproduced video signal output is provided, and copy information in compliance with copy information contained in the reproduced signal is added and delivered. In a recording apparatus, a detection circuit (7) for detecting copy information in an inputted video signal is provided, and permission/inhibition of copy is controlled on the basis of the detected copy information and when copy is permitted, necessary copy information is generated and added to a recording signal.

    摘要翻译： 在再现设备中，提供了用于在再现视频信号输出的垂直消隐时段期间添加复制信息的发生器电路（9），并且添加并传送与包含在再现信号中的复制信息一致的复制信息。 在记录设备中，提供用于检测输入视频信号中的复制信息的检测电路（7），并且基于检测到的复制信息来控制复制的允许/禁止，并且当允许复制时，生成必要的复制信息 并添加到记录信号。