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    Magnetic reproduction apparatus for reproducing a video signal
    1.
    发明授权
    Magnetic reproduction apparatus for reproducing a video signal 失效
    用于再现视频信号的磁再现装置

    公开(公告)号：US5377053A

    公开(公告)日：1994-12-27

    申请号：US910757

    申请日：1992-07-08

    申请人： Soichi Iwamura ,  Junichi Aoki ,  Hiroaki Nogami

    发明人： Soichi Iwamura ,  Junichi Aoki ,  Hiroaki Nogami

    IPC分类号： G11B20/02 ,  G11B20/06 ,  H04N5/922 ,  H04N9/797 ,  H04N9/80 ,  H04N9/81 ,  H04N9/87 ,  H04N9/896 ,  H04N5/78

    CPC分类号： H04N9/896 ,  H04N9/7973 ,  H04N9/81

    摘要： A magnetic reproduction apparatus which uses a magnetic recording medium on which frequency-modulated signals produced by frequency-modulating a carrier with video signals are recorded, and demodulates reproduced signals from the magnetic recording medium into the video signals. The apparatus includes a frequency convertor for causing the reproduced signals to shift to a higher frequency region and a pulse-count-type FM demodulator for demodulating the reproduced signals which have shifted to the higher frequency region into the video signals. This arrangement restrains the mixing of the reproduced signals in the video signals. Therefore the video signals are reproduced with lessened waveform distortion, achieving a high-quality image.

    摘要翻译： 一种使用磁记录介质的磁再现装置，其中记录了通过对具有视频信号的载波进行频率调制而产生的调频信号，并将从磁记录介质再现的信号解调成视频信号。 该装置包括用于使再现信号转换到较高频率区域的频率转换器和用于将已经转移到较高频率区域的再现信号解调为视频信号的脉冲计数型FM解调器。 这种布置限制了视频信号中的再现信号的混合。 因此，以更小的波形失真再现视频信号，实现高质量的图像。

    Magnetic reproducing apparatus for reproducing a video signal from a magnetic recording medium
    2.
    发明授权
    Magnetic reproducing apparatus for reproducing a video signal from a magnetic recording medium 失效
    用于从磁记录介质再现视频信号的磁再现装置

    公开(公告)号：US5260838A

    公开(公告)日：1993-11-09

    申请号：US708927

    申请日：1991-05-31

    申请人： Soichi Iwamura ,  Hiroaki Nogami

    发明人： Soichi Iwamura ,  Hiroaki Nogami

    IPC分类号： H04N5/922 ,  G11B20/06 ,  H04N5/92 ,  H04N9/89

    CPC分类号： H04N5/92 ,  H04N9/89

    摘要： An FM carrier is FM-modulated with a video signal for recordal on a magnetic medium. The phase of the FM carrier corresponding to a tip portion of a horizontal synchronizing pulse in the video signal is reset to, and the phase is fixed at, a reference phase at a leading edge of the horizontal synchronizing pulse and is fixed during every period of the horizontal synchronizing pulse width. In reproducing the video signal, the FM carrier, with its frequency doubled, is demodulated by a pulse count type FM demodulator having a frequency-doubling function. The FM carrier is always maintained in phase with the horizontal synchronizing pulse in the video signal, so that beat stripes or moire do not appear on the reproduced picture, and interference due to the leakage appears as reproduced picture distortion in correlation with the video signal. A reference burst signal necessary to a time base correction is extracted from the reproduced FM carrier.

    Carrier reset FM modulator and method of frequency modulating video signals
    3.
    发明授权
    Carrier reset FM modulator and method of frequency modulating video signals 失效
    载波复位FM调制器和频率调制视频信号的方法

    公开(公告)号：US5157359A

    公开(公告)日：1992-10-20

    申请号：US667941

    申请日：1991-03-12

    申请人： Hiroaki Nogami ,  Soichi Iwamura

    发明人： Hiroaki Nogami ,  Soichi Iwamura

    IPC分类号： H04N5/95 ,  G11B20/06 ,  H03C3/09 ,  H04N5/92

    CPC分类号： H04N5/92 ,  H03C3/09

    摘要： An FM modulator includes a base clock generating circuit (7) receiving an incoming video signal for generating an AFC reference frequency signal having a frequency and phase corresponding to a horizontal synchronizing signal of the incoming video signal, a first carrier reset pulse having the same frequency as the horizontal synchronizing signal and a second carrier reset pulse whose frequency is an integer mutliple of that of the horizontal synchronizing signal. The second reset pulse is generated at a timing speed lagged behind the first reset pulse. The FM modulator further includes an adder (3) for adding the first reset pulse to the incoming video signal for lowering the DC level at the leading edge portion of the horizontal synchronizing signal, and an oscillator (9, 9a, 9b, 10, 10a, 10b) whose oscillation frequency is changed dependent on the DC level of the output signal from the adder to produce a carrier FM modulated by the video signal. The oscillator is reset by the second reset pulse.

    Recording-reproduction apparatus applying double reset to the phase of an FM carrier
    6.
    发明授权
    Recording-reproduction apparatus applying double reset to the phase of an FM carrier 失效
    记录再生装置对FM载波的相位进行双重复位

    公开(公告)号：US5355226A

    公开(公告)日：1994-10-11

    申请号：US831214

    申请日：1992-02-07

    申请人： Hiroaki Nogami ,  Soichi Iwamura

    发明人： Hiroaki Nogami ,  Soichi Iwamura

    IPC分类号： H04N9/797 ,  H04N9/83 ,  H04N9/89 ,  H04N9/80

    CPC分类号： H04N9/797 ,  H04N9/83 ,  H04N9/89

    摘要： A magnetic recording-reproduction apparatus records and reproduces a wide-band video signal without a color burst signal. For this purpose, a two-step phase resetting operation is conducted on the FM carrier at the front porch and the horizontal sync pulse of the video signal so as to permit those phases to coincide with reference phases. A synchronizing panel clock generator generates the first reference signal with the first FM frequency corresponding to a peak level of the horizontal sync pulse and the second reference signal with the second FM frequency corresponding to a front porch level. In this case, the reference signals are phase-synchronous with each other at the leading edge of the horizontal sync pulse, and each of the FM frequencies is set to be an integer multiple of the horizontal scanning frequency. In another arrangement, a secondary FM carrier whose frequency has been shifted to a low-band is formed by generating a frequency conversion signal synchronous with the horizontal sync pulse and combining the phase-reset FM carrier with the frequency conversion signal. Either of the above arrangements can eliminate unwanted higher harmonic wave components and transient distortions in the frequency-demodulated output, thereby improving the image quality.

    摘要翻译： 磁记录再现装置记录并再现没有色同步信号的宽带视频信号。 为此，在前沿的FM载波和视频信号的水平同步脉冲上进行两步相位复位操作，以允许这些相位与参考相位一致。 同步面板时钟发生器产生第一参考信号，其中第一FM频率对应于水平同步脉冲的峰值电平，第二参考信号具有对应于前沿电平的第二FM频率。 在这种情况下，参考信号在水平同步脉冲的前沿彼此相位同步，并且每个FM频率被设置为水平扫描频率的整数倍。 在另一种布置中，通过产生与水平同步脉冲同步的频率转换信号并将相位复位FM载波与频率转换信号组合，形成频率已经移位到低频带的次级FM载波。 上述任一种可以消除频率解调输出中的不需要的高次谐波分量和瞬态失真，从而提高图像质量。