Code modulation system
    1.
    发明授权
    Code modulation system 失效
    码调制系统

    公开(公告)号:US4628297A

    公开(公告)日:1986-12-09

    申请号:US696477

    申请日:1985-01-30

    CPC分类号: G11B20/1426

    摘要: In the code modulation system for converting input data levels into an output signal in the form of code words by providing M input levels among N input levels assigned to input data with stairlike code weights on the basis of the input levels, (N-M) input levels which are the difference between said N input levels and said M input levels are respectively disposed near transition points where said stairlike code weight is changed, and the code weights are provided with hysteresis in the ascent process and the descent process of the input data level.

    摘要翻译: 在用于将输入数据电平转换为码字形式的输出信号的码调制系统中,通过在分配给输入数据的N个输入电平之间提供基于输入电平的阶梯式码权重的M个输入电平,(NM)输入电平 所述N个输入电平和所述M个输入电平之间的差别分别设置在所述阶梯式码权重改变的过渡点附近,并且在上升处理中的代码权重和输入数据电平的下降处理被赋予滞后。

    Method of correcting errors of digital signals in the recording and
reproduction of digital signals
    2.
    发明授权
    Method of correcting errors of digital signals in the recording and reproduction of digital signals 失效
    在数字信号的记录和再现中校正数字信号的误差的方法

    公开(公告)号:US4661956A

    公开(公告)日:1987-04-28

    申请号:US703917

    申请日:1985-02-21

    摘要: Parity bits (check bits) having a relatively high redundancy are added to upper significant bits of a digital signal, and parity bits having a relatively low redundancy, are added to the lower significant bits of the digital signal. The signal and the parity bits are recorded on a recording medium. The position of an error in a data block group of the lower bits reproduced from the recording medium is estimated as existing in a block in which the error is detected by the check of the data block group of the upper bits, and in the blocks preceding and subsequent to the former.This error correction method is most suitable for a recording and reproduction system of digital video signals.

    摘要翻译: 具有较高冗余度的奇偶校验位(校验位)被添加到数字信号的高有效位,并且具有较低冗余度的奇偶校验位被添加到数字信号的较低有效位。 信号和奇偶校验位被记录在记录介质上。 从记录介质再现的低位的数据块组中的误差的位置被估计为存在于通过对高位的数据块组的检查检测出错误的块中,以及在前一个块 并在之前。 该纠错方法最适用于数字视频信号的记录和再现系统。

    Method for decoding double-encoding codes and apparatus using the same
    4.
    发明授权
    Method for decoding double-encoding codes and apparatus using the same 失效
    用于对双重编码码进行解码的方法及使用其的装置

    公开(公告)号:US4653052A

    公开(公告)日:1987-03-24

    申请号:US750513

    申请日:1985-07-01

    IPC分类号: G06F11/10 H03M13/27 H03M13/29

    CPC分类号: H03M13/29

    摘要: The present invention relates to a method and an apparatus for decoding double-encoding codes in which the information to be decoded comprises a first data and a second data. The operation for decoding double-encoding codes is achieved through two stages. A decoder of the first stage checks the first data, and when an error is found in the first data, all symbols of the first data are assumed to be wrong. The first-stage decoder then adds an erasure flag to all symbols to generate erasure symbols. As a result, these erasure symbols include the symbols which are actually erroneous and those which are correct. A decoder of the second stage is used to perform an error correction on the second data. For this purpose, the second-stage decoder detects the number of erasure symbols which are contained in the second data and which are actually erroneous. If the number of actually erroneous symbols does not exceed the maximum number of correctable symbols which can be corrected by the decoder of the second stage, the error correction is effected; otherwise, the decoder detects an error without conducting the error correction.

    摘要翻译: 本发明涉及一种用于解码双重编码码的方法和装置,其中待解码的信息包括第一数据和第二数据。 双编码解码操作通过两个阶段实现。 第一级的解码器检查第一数据,并且当在第一数据中发现错误时,假定第一数据的所有符号是错误的。 然后,第一级解码器将擦除标志添加到所有符号以产生擦除符号。 结果,这些擦除符号包括实际上是错误的符号和正确的符号。 第二级的解码器用于对第二数据执行纠错。 为此,第二级解码器检测包含在第二数据中并且实际上是错误的擦除符号的数量。 如果实际错误符号的数量不超过可由第二级的解码器校正的可校正符号的最大数目,则进行纠错; 否则,解码器在不进行纠错的情况下检测到错误。

    Method and apparatus for generating error correction codes for digitized
picture signal recording/reproducing
    5.
    发明授权
    Method and apparatus for generating error correction codes for digitized picture signal recording/reproducing 失效
    用于产生用于数字化图像信号记录/再现的纠错码的方法和装置

    公开(公告)号:US4698811A

    公开(公告)日:1987-10-06

    申请号:US756706

    申请日:1985-07-19

    摘要: An apparatus for recording or reproducing codes resulting from digitalizing a picture signal on or from a video tape recorder includes a device for correcting code error produced due to interference in the course of recording or reproducing process. The pixel codes succeeding to one another in time are divided to high-order and low-order bit-blocks, respectively, wherein the high-order bits are used to constitute a pseudo pixel code which is then added with a pixel error correcting code. The pixel code consisting of the high-order bits is added with a bit error correcting code before being recorded. In reproduction, error correction can be realized at higher rate with the aid of the correction codes to improve the quality of reproduced picture.

    摘要翻译: 用于记录或再现由视频磁带录像机上的图像信号数字化所产生的代码的装置包括用于在记录或再现处理过程中纠正由于干扰而产生的码错误的装置。 在时间上彼此相继的像素码分别被分割为高阶位和低位位块,其中高阶位用于构成伪像素码,然后加上像素误差校正码。 由高位构成的像素码在记录之前加上位纠错码。 在再现中,借助于校正码可以以更高的速率实现纠错,以提高再现画面的质量。

    Adaptive transform encoder for digital image signal in
recording/reproducing apparatus
    7.
    发明授权
    Adaptive transform encoder for digital image signal in recording/reproducing apparatus 失效
    用于记录/再现装置中的数字图像信号的自适应变换编码器

    公开(公告)号:US5047852A

    公开(公告)日:1991-09-10

    申请号:US375727

    申请日:1989-07-05

    摘要: An adaptive transform encoder can keep a recording rate of a digital signal at a constant level. It comprises a unit for orthogonal-transforming one block of digital input signal, a unit for calculating an activity index of the orthogonal-transformed block, a unit for comparing the activity index of the block with a predetermined reference, a unit for classifying the block to a standard bit class having a predetermined number of bits when the activity index of the block is equal to the reference, classifying the block to a low bit class having a smaller number of bits than the predetermined number of bits of the standard bit class when the activity index of the block is smaller than the reference, and classifying the block to a high bit class having a larger number of bits than the predetermined number of bits of the standard bit class when the activity index is larger than the reference, a quantization unit for quantizing the input signal of the block with the number of bits designated by the bit class, a unit for selecting the block of the low bit class from the quantized blocks, an allocation unit for adding to the selected block of the low bit class the data having more bits than the number of bits of the standard bit class of the block of the quantized high bit class, and an encoder unit for encoding the quantized block signal.

    摘要翻译: 自适应变换编码器可以将数字信号的记录速率保持在恒定水平。 它包括用于正交变换一个数字输入信号块的单元,用于计算正交变换块的活动索引的单元,用于将块的活动性指数与预定参考进行比较的单元,用于对块进行分类的单元 当块的活动索引等于参考时,将具有预定比特数的标准比特类分类为具有比标准比特类的预定比特数少的比特数比特的低比特级, 该块的活动指数小于参考值,并且当活动指数大于参考值时,将块分类为具有比标准比特类的预定比特数大的比特数的比特数较大的高比特级,量化 用于通过由位类别指定的比特数量量化块的输入信号的单元,用于从量化块中选择低比特等级的块的单元 分配单元,用于向所选择的低位类别的块添加比量化高位类别的块的标准位类别的位数多的位的数据,以及用于对量化块信号进行编码的编码器单元 。

    Demodulation apparatus
    8.
    发明授权
    Demodulation apparatus 失效
    解调装置

    公开(公告)号:US4983965A

    公开(公告)日:1991-01-08

    申请号:US444845

    申请日:1989-12-04

    IPC分类号: G11B20/14 H03M5/14

    CPC分类号: H03M5/14

    摘要: An original digital signal is converted into either a Miller-squared code signal or a Miller code signal, and undergoes serial-to-parallel conversion to produce n-phase signals (where n is desired to be a positive even number). N-phase virtual demodulated signals are simultaneously generated at clock timing having a period equivalent to 1/n times the period of the transmission clock. Out of the n-phase virtual demodulated signals, n/2 phases are selected to undergo parallel-to-serial conversion, the original digital signal being thus obtained.

    摘要翻译: 原始数字信号被转换成米勒平方码信号或米勒码信号,并进行串并转换以产生n相信号(其中n希望为正偶数)。 在具有相当于传输时钟的周期的1 / n倍的周期的时钟定时处同时产生N相虚拟解调信号。 在n相虚拟解调信号中,选择n / 2相进行并行到串行转换,从而获得原始数字信号。

    Optical tape apparatus with a tracking control mechanism and/or a
focusing control mechanism
    9.
    发明授权
    Optical tape apparatus with a tracking control mechanism and/or a focusing control mechanism 失效
    具有跟踪控制机构和/或聚焦控制机构的光带装置

    公开(公告)号:US4970707A

    公开(公告)日:1990-11-13

    申请号:US239389

    申请日:1988-09-01

    IPC分类号: G11B7/003 G11B7/09

    摘要: An optical tape apparatus having improved focus and tracking control. An optical head records, reproduces, or rewrites data on an optical tape by helically scanning the tape with a laser beam. A guide plate is disposed between the optical head and the tape to prevent the beam from becoming unfocused due to fluctuation of the tape cuased by an air film between the optical head and the tape. The optical head contains a semiconductor laser and an optical system exhibiting chromatic aberration for directing the laser beam onto the tape. The optical system includes a condenser lens for focusing the beam onto the tape. Fine focus control is achieved by changing the wavelength of the laser beam by directing part of the beam reflected from the tape back to the laser, thereby changing the focal point of the beam by virtue of the chromatic aberration of the optical system. Coarse focus control is achieved by mounting the condenser lens on a piezoelectric actuator which moves the consenser lens to focus the beam onto the tape. A recording head for recording timing marks and tracking signals on the tape is disposed in advance of the optical head. A reading head reads the timing marks and the optical head reads the tracking signals. The timing marks and tracking signals are used to control the operation of the apparatus such that the tape is transported with a constant speed and data on diagonal signal tracks on the tape is accurately recorded, reproduced, or rewritten.

    摘要翻译: 具有改进的聚焦和跟踪控制的光带装置。 光学头通过用激光束螺旋扫描磁带来记录,再现或重写光学带上的数据。 引导板设置在光头和带之间,以防止由于光头和带之间的空气膜带来的带的波动而导致光束不聚焦。 光头包含半导体激光器和具有用于将激光束引导到带上的色差的光学系统。 光学系统包括用于将光束聚焦到胶带上的聚光透镜。 通过将从带反射的光束的一部分引回到激光器来改变激光束的波长,从而通过光学系统的色差来改变光束的焦点来实现精细对焦控制。 通过将聚光透镜安装在压电致动器上来实现粗调焦控制,该压电致动器移动辅助透镜以将光束聚焦到带上。 在光学头之前设置用于在带上记录定时标记和跟踪信号的记录头。 读头读取定时标记,光头读取跟踪信号。 定时标记和跟踪信号用于控制装置的操作,使得磁带以恒定速度传送,并且磁带上对角线信号轨道上的数据被精确地记录,再现或重写。

    Apparatus for recording/reproducing digital video signals in both a
standard mode and a long playing mode
    10.
    发明授权
    Apparatus for recording/reproducing digital video signals in both a standard mode and a long playing mode 失效
    用于在标准模式和长播放模式下记录/再现数字视频信号的装置

    公开(公告)号:US4963992A

    公开(公告)日:1990-10-16

    申请号:US301462

    申请日:1989-01-26

    CPC分类号: H04N9/797 H04N5/926

    摘要: An apparatus for recording an reproducing a digital video signal is disclosed which includes n sampling circuits each for performing a sub-Nyquist sampling operation for the digital video signal in such a manner that the amount of data is reduced to one-n-th of an original amount (where n is a positive integer) and a pixel sampled by the sub-Nyquist sampling operation is not sampled by the remaining sampling circuits, recording/reproducing means for recording and reproducing information at all or part of pixels which are sampled by the n sampling circuits and a device for reconstructing the digital video signal from reproduced information at pixels with the aid of a synthesizing technique or interpolation technique.

    摘要翻译: 公开了一种用于记录再现数字视频信号的装置,其包括n个采样电路,每个采样电路用于对数字视频信号执行子奈奎斯特采样操作,使得数据量减少到数字视频信号的1 / 原始量(其中n是正整数)和通过亚奈奎斯特采样操作采样的像素不被剩余的采样电路采样,用于在全部或部分像素记录和再现信息的记录/再现装置 n个采样电路和用于通过合成技术或插值技术在像素处从再现信息重构数字视频信号的装置。