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公开(公告)号：US5119243A
公开(公告)日：1992-06-02
申请号：US452380
申请日：1989-12-19
申请人： Hiroaki Shimazaki , Toyohiko Matsuta , Etsuto Nakatsu , Masafumi Shimotashiro , Masaaki Kobayashi
发明人： Hiroaki Shimazaki , Toyohiko Matsuta , Etsuto Nakatsu , Masafumi Shimotashiro , Masaaki Kobayashi
CPC分类号： G11B20/10222 , G11B20/10009 , G11B20/1403 , G11B20/1496 , G11B5/09 , H03M5/20
摘要： A digital signal magnetic recording/reproducing apparatus modulates a digital signal with a carrier and performs recording/reproducing of the modulated signal. The carrier frequency is made equal to the clock frequency multiplied by a factor (N/M), where N and M are integers. The carrier and clock are reproduced using only one phase locked loop. When the carrier-modulated signal is recorded/reproduced using a magnetic recording medium, the phase of the modulated signal is shifted relative to the phase of the carrier. Shifting the clock phase before using the clock for decoding the demodulated signal prevents a degradation of error rate. By periodically inserting a clock phase reference signal in the recording signal, accuracy of adjustment of clock phase is improved.
摘要翻译： 数字信号磁记录/再现装置用载波调制数字信号并执行调制信号的记录/再现。 载波频率等于时钟频率乘以因子（N / M），其中N和M是整数。 载波和时钟仅使用一个锁相环进行复制。 当使用磁记录介质记录/再现载波调制信号时，调制信号的相位相对于载波的相位移位。 在使用时钟解码解调信号之前切换时钟相位可防止错误率的降低。 通过在记录信号中周期性地插入时钟相位参考信号，提高了时钟相位的调整精度。
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公开(公告)号：US5062007A
公开(公告)日：1991-10-29
申请号：US450997
申请日：1989-12-15
申请人： Etsuto Nakatsu , Hiroaki Shimazaki , Toyohiko Matsuta , Masafumi Shimotashiro , Masaaki Kobayashi
发明人： Etsuto Nakatsu , Hiroaki Shimazaki , Toyohiko Matsuta , Masafumi Shimotashiro , Masaaki Kobayashi
CPC分类号： G11B20/10
摘要： A digital signal magnetic recording/reproducing apparatus converts a digital signal into a multi-value digital signal, followed by recording/reproducing the quadrature biphase modulated multi-value quadrature amplitude modulated signal. By using a multi-value quadrature amplitude modulation, a direct current component in the recorded signal can be eliminated, and the utilization efficiency of the recording frequency band of the digital signal magnetic recording/reproducing apparatus can be improved. Also, with respect to the amplitude non-linear characteristic which occurs in the magnetic recording/reproducing process, by providing a compensating circuit during the mapping before recording or after reproducing and demodulating, the deterioration of the S/N ratio of the reproduced and demodulated signal can be reduced to decrease the errors in the decoded data. Furthermore by bias-recording the multi-value quadrature amplitude modulation signal, the non-linearity of the electromagnetic conversion system is alleviated to decrease the deterioration of the S/N ratio due to distortion, thereby making the application of the modulation scheme more reliable.
摘要翻译： 数字信号磁记录/再现装置将数字信号转换为多值数字信号，随后记录/再现正交双相调制多值正交幅度调制信号。 通过使用多值正交幅度调制，可以消除记录信号中的直流分量，并且可以提高数字信号磁记录/再现装置的记录频带的利用效率。 此外，关于在磁记录/再现处理中发生的振幅非线性特性，通过在记录之前或再现和解调之后的映射期间提供补偿电路，再现和解调的S / N比的恶化 可以减少信号以减少解码数据中的误差。 此外，通过对多值正交幅度调制信号进行偏置记录，可以减轻电磁转换系统的非线性，以减少由于失真引起的S / N比的恶化，从而使得调制方案的应用更可靠。
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3.发明授权
公开(公告)号：US5124861A
公开(公告)日：1992-06-23
申请号：US329720
申请日：1989-03-28
申请人： Masafumi Shimotashiro , Toyohiko Matsuta , Masaaki Kobayashi , Etsuto Nakatsu , Hiroaki Shimazaki
发明人： Masafumi Shimotashiro , Toyohiko Matsuta , Masaaki Kobayashi , Etsuto Nakatsu , Hiroaki Shimazaki
CPC分类号： H04L27/362 , G11B20/10 , G11B20/14 , H04L27/3836 , H04N5/926 , H04N5/935 , H04N9/8722
摘要： A digital signal magnetic recording and playback apparatus which is applicable to digital video signals, utilizes quadrature amplitude modulation to produce a recording signal from a digital input signal with a carrier frequency being employed which is less than or equal to than the frequency of a recording system clock signal that is synchronized with the successive data values of the digital input signal. Carrier bursts are periodically inserted into the recording signal with a fixed period, through data inserted by a burst data insertion circuit and the carrier and clock signal are arranged to periodically coincide in phase, with the aforementioned period. The carrier frequency is made equal to the clock frequency multiplied by a factor (n/m), where n and m are integers and n
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4.发明授权Digital signal magnetic recording/reproducing apparatus using multi-level QAM modulation and maximum likelihood decoding 失效使用多级QAM调制和最大似然解码的数字信号磁记录/再现装置
公开(公告)号：US5095392A
公开(公告)日：1992-03-10
申请号：US302325
申请日：1989-01-27
CPC分类号： H03M13/41 , G11B20/1496 , G11B20/1809 , G11B20/1833 , G11B5/09 , H03M13/25 , H03M13/39 , H03M5/20 , H04L27/3438 , H04N5/926
摘要： A digital signal magnetic recording/reproducing apparatus converts a digital signal into multi-value digital signals and performs recording/reproducing of a multi-value quadrature amplitude-modulated signal. By using the multi-value quadrature amplitude modulation, it is possible to remove the DC component in the recording signal and improve the utilization efficiency of the recording frequency band. Further, using a system to memorize the frequency characteristic of the magnetic recording/reproducing unit and effect Viterbi decoding regarding the intersymbol interference caused by the frequency as a convolutional coding, it is possible to detect the level without necessitating frequency equalization. Accordingly, there arises no deterioration of the S/N ratio by frequency equalization. Furthermore, by providing an encoder for error control coding by increasing the number of multi-values and a corresponding decoder, the error rate can be improved against the deterioration of the S/N ratio. Further, by bias recording the multi-value quadrature amplitude modulated signal, non-linearity of the electromagnetic conversion system is relaxed, and deterioration of the S/N ratio by distortion is improved.
摘要翻译： 数字信号磁记录/再现装置将数字信号转换为多值数字信号，并执行多值正交幅度调制信号的记录/再现。 通过使用多值正交幅度调制，可以去除记录信号中的DC分量并提高记录频带的利用效率。 此外，使用系统来存储磁记录/再现单元的频率特性，并且将由频率引起的码间干扰作为卷积编码进行维特比解码，可以在不需要频率均衡的情况下检测电平。 因此，通过频率均衡不会导致S / N比的恶化。 此外，通过提供用于通过增加多值的数量的差错控制编码的编码器和相应的解码器，可以相对于S / N比的劣化来提高错误率。 此外，通过偏置记录多值正交幅度调制信号，电磁转换系统的非线性松弛，并且通过失真降低S / N比。
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公开(公告)号：US4979052A
公开(公告)日：1990-12-18
申请号：US251094
申请日：1988-09-29
摘要： A digital signal magnetic recording/reproducing apparatus converts a digital signal into a multi-value quadrature amplitude modulated signal, and records and reproduces the multi-value quadrature amplitude modulated signal. By using the multi-value quadrture amplitude modulation, any DC component in the recording signal is removed and utilization efficiency of the recording frequency band can be improved. By bias recording of the multi-value quadrature amplitude modulated signal, non-linearity of the electromagnetic of conversion system is reduced, and deterioration of SN ratio due to distortion is improved.
摘要翻译： 数字信号磁记录/再现装置将数字信号转换为多值正交幅度调制信号，并记录和再现多值正交幅度调制信号。 通过使用多值二次振幅调制，去除记录信号中的任何DC分量，并且可以提高记录频带的利用效率。 通过多值正交幅度调制信号的偏置记录，转换系统的电磁场的非线性减小，并且由于失真引起的SN比的恶化得到改善。
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公开(公告)号：US5255127A
公开(公告)日：1993-10-19
申请号：US724888
申请日：1991-07-02
CPC分类号： H04L1/0047 , G11B20/10009 , H03M13/39 , H04L1/0054
摘要： In transmission or recording of a digital signal by means of digital amplitude and phase modulation, particularly recording into and reproducing the same from the a magnetic recording medium, a digital amplitude/phase modulated signal to be demodulated is commonly affected by the non-linear amplitude characteristics and the effects of unwanted jitter and envelope variation. As the result, the error rate of decoded data will be increased. For compensation, the Viterbi decoding technique is employed with the use of a weighted distance value calculated by multiplying an Euclidean distance between the signal point of a reproduction signal and the datum point of each code by a positive weighting factor which is determined smaller when the code datum point is located further from the origin point of a coordinate system. Accordingly, the weighted distance of each reproduction signal point from its corresponding datum point can approximately be uniform thus ensuring less error decoding in general.
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7.发明授权
公开(公告)号：US5465158A
公开(公告)日：1995-11-07
申请号：US409964
申请日：1995-03-24
CPC分类号： H04N9/83 , H04N9/8205
摘要： In a video tape recorder of the color under recording type, in which a low frequency band converted carrier chrominance signal is recorded together with an FM luminance signal, another FM modulator is provided for modulating a wide band chrominance signal. An additional head records the FM chrominance signal on at least a part of a track on which video signal has been recorded in the color under recording. In reproduction, it is checked whether the FM chrominance signal is reproduced or not for selecting the FM chrominance signal or the color under recorded carrier chrominance signal as a reproduced chrominance signal output.
摘要翻译： 在与FM亮度信号一起记录低频带转换载波色度信号的记录类型的彩色录像机中，提供另一FM调制器用于调制宽带色度信号。 附加的头在记录有颜色的视频信号的轨道的至少一部分上记录FM色度信号。 在再现中，检查FM色度信号是否被再现，用于选择FM色度信号或记录载波色度信号下的颜色作为再现的色度信号输出。
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8.发明授权Digital signal magnetic recording/reproducing apparatus using amplitude phase shift keying and frequency-multiplexing 失效使用幅度相移键控和频率复用的数字信号磁记录/再现装置
公开(公告)号：US5402272A
公开(公告)日：1995-03-28
申请号：US178623
申请日：1994-01-07
申请人： Etsuto Nakatsu , Haruo Ohta , Masaaki Kobayashi
发明人： Etsuto Nakatsu , Haruo Ohta , Masaaki Kobayashi
CPC分类号： G11B20/10
摘要： A digital signal magnetic recording/reproducing apparatus subjects a digital signal to a digital amplitude phase shift keying and records and reproduces the modulated signal thus obtained on a magnetic recording medium. Use of the digital amplitude phase shift keying technique makes it possible to remove the direct-current component in the recording signals, and to improve the utilization efficiency of the recording frequency band, thus making high density recording possible. In addition, since a plurality of modulated signals are frequency-multiplexed and recorded, almost the entire frequency band recordable on a magnetic recording medium can be utilized, resulting in an increase in recording density. Further in addition, a pilot signal produced by frequency-converting a carrier is frequency-multiplexed with a modulated signal and recorded and reproduced and the carrier is reproduced from the reproduced pilot signal, so that a redundant part for reproducing the carrier is not necessary.
摘要翻译： 数字信号磁记录/再现装置使数字信号进行数字幅度相移键控，并记录并再现由磁记录介质获得的调制信号。 使用数字幅度相移键控技术可以消除记录信号中的直流分量，并提高记录频带的利用效率，从而使得高密度记录成为可能。 此外，由于多个调制信号被频率复用和记录，所以可以利用可记录在磁记录介质上的几乎整个频带，导致记录密度的增加。 此外，通过对载波进行频率转换而产生的导频信号与调制信号进行频率复用并被记录和再现，并且从再现的导频信号再现载波，从而不需要用于再现载波的冗余部分。
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公开(公告)号：US5335125A
公开(公告)日：1994-08-02
申请号：US969482
申请日：1992-10-30
IPC分类号： G11B5/008 , G11B15/12 , G11B15/18 , G11B15/467 , H04N5/765 , H04N5/7826 , H04N5/926 , H04N5/945 , H04N9/79 , H04N9/83 , H04N5/78
CPC分类号： G11B15/1875 , G11B15/125 , H04N5/9264 , H04N5/9268 , H04N9/7921 , H04N9/83 , G11B15/4673 , H04N5/945
摘要： A video tape recorder capable of recording a normal definition video signal and a high definition video signal having an image quality higher than the normal one in a simulcast for broadcasting an identical program in a conventional broadcasting system and a high definition system. The common video signal is recorded in a conventional analog signal format at a tape feeding speed of the normal mode by an EP mode head defining a tracking width narrower than that of a standard mode head, while the high definition video signal is recorded in a digital form by a high definition video head additionally mounted on a rotary drum. Additionally, a common video signal recorded by a conventional video tape recorder can be reproduced.
摘要翻译： 一种能够记录正常清晰度视频信号的磁带录像机和具有高于普通视频信号的图像质量的高分辨率视频信号，用于在常规广播系统和高分辨率系统中广播相同节目。 公共视频信号以常规模式信号格式以通常模式的磁带馈送速度通过限定比标准模式磁头窄的跟踪宽度的EP模式磁头记录，而高分辨率视频信号被记录在数字 通过另外安装在旋转鼓上的高清晰度视频头来形成。 此外，可以再现由常规磁带录像机记录的公共视频信号。
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10.发明授权Apparatus for demodulating and decoding multi-level amplitude modulation signal conveying digital data 失效用于解调和解码传送数字数据的多电平幅度调制信号的装置
公开(公告)号：US5233479A
公开(公告)日：1993-08-03
申请号：US591240
申请日：1990-10-01
申请人： Etsuto Nakatsu , Haruo Ohta , Masaaki Kobayashi
发明人： Etsuto Nakatsu , Haruo Ohta , Masaaki Kobayashi
摘要： An apparatus for demodulating and decoding a multi-level amplitude modulation signal used to convey digital data, such as a QAM signal, having amplitude modulated carrier components differing in phase. The apparatus derives demodulated data values from that signal, and derives from average values of sets of these data values a set of compensated reference point data respectively corresponding to signal reference points of the multi-level modulation signal which are expressible as a symbol constellation in the I-Q plane. The compensated reference point data are used to obtain correct digital code values from the demodulated data, even if there is considerable distortion of the multi-level amplitude modulated signal, as is the case for such a signal when recorded and reproduced from a magnetic recording medium.
摘要翻译： 一种用于解调和解码用于传送诸如QAM信号的数字数据的多电平幅度调制信号的装置，其具有相位不同的幅度调制载波分量。 该装置从该信号导出解调的数据值，并且从这些数据值的集合的平均值中导出分别对应于多电平调制信号的信号参考点的一组补偿参考点数据，这些参考点数据可表示为 智商飞机。 补偿参考点数据用于从解调数据获得正确的数字码值，即使在多电平幅度调制信号存在相当大的失真的情况下，如在从磁记录介质记录和再现时的这种信号的情况 。
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