FM demodulator
    1.
    发明授权
    FM demodulator 失效
    FM解调器

    公开(公告)号:US4629994A

    公开(公告)日:1986-12-16

    申请号:US743369

    申请日:1985-06-11

    IPC分类号: H03D3/00

    CPC分类号: H03D3/00

    摘要: An FM signal demodulator has a phase shifter including transversal filters for producing from a FM video signal two FM video signals which are different in phase by 90.degree. from each other, and a demodulator for detecting phase information of the FM video signal, wherein the carrier frequency is at least quadrupled prior to demodulation so as to suppress components of the FM video signal not to be included in the demodulated video signal.

    摘要翻译: FM信号解调器具有移相器,该移相器包括横向滤波器,用于从FM视频信号产生相位相差90°的两个FM视频信号,以及用于检测FM视频信号的相位信息的解调器,其中载波 频率在解调之前至少是四倍,以便抑制FM视频信号中不包括在解调视频信号中的分量。

    Digital signal magnetic recording/reproducing apparatus
    2.
    发明授权
    Digital signal magnetic recording/reproducing apparatus 失效
    数字信号磁记录/重放装置

    公开(公告)号:US5119243A

    公开(公告)日:1992-06-02

    申请号:US452380

    申请日:1989-12-19

    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。

    Digital signal magnetic recording/reproducing apparatus
    3.
    发明授权
    Digital signal magnetic recording/reproducing apparatus 失效
    数字信号磁记录/重放装置

    公开(公告)号:US4979052A

    公开(公告)日:1990-12-18

    申请号:US251094

    申请日:1988-09-29

    IPC分类号: G11B5/09 G11B20/10

    CPC分类号: G11B20/10 G11B5/09

    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。

    Digital signal magnetic recording/reproducing apparatus using
multi-level QAM modulation and maximum likelihood decoding
    5.
    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

    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。

    Digital signal magnetic recording/reproducing apparatus
    6.
    发明授权
    Digital signal magnetic recording/reproducing apparatus 失效
    数字信号磁记录/重放装置

    公开(公告)号:US5062007A

    公开(公告)日:1991-10-29

    申请号:US450997

    申请日:1989-12-15

    IPC分类号: G11B5/09 G11B20/10

    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。

    Video signal reproduction apparatus
    7.
    发明授权
    Video signal reproduction apparatus 失效
    视频信号再生装置

    公开(公告)号:US4704639A

    公开(公告)日:1987-11-03

    申请号:US842802

    申请日:1986-03-21

    IPC分类号: H04N9/83

    CPC分类号: H04N9/83

    摘要: A video signal reproduction apparatus for reproducing a composite color video signal from a recording medium. A signal reproduced from the recording medium is divided into a frequency-modulated (FM) signal and a low-band-converted signal by filters. The FM signal is demodulated by a demodulater into a luminance signal. A first conversion circuit produces from the low-band-converted signal a chrominance signal without a phase jitter component. A second conversion circuit produces from the low-band-converted signal a high-band component of luminance signal with a same phase jitter component as that of the luminance signal obtained from the demodulator. The luminance signal from the demodulator, the high-band component of luminance signal and the chrominance signal are mixed to obtain the composite color video signal.

    摘要翻译: 一种用于从记录介质再现合成彩色视频信号的视频信号再现装置。 从记录介质再现的信号通过滤波器被分成调频(FM)信号和低频带转换信号。 FM信号由解调器解调成亮度信号。 第一转换电路从低频带转换信号产生没有相位抖动分量的色度信号。 第二转换电路从低频带转换信号产生具有与从解调器获得的亮度信号相同的相位抖动分量的亮度信号的高频带分量。 来自解调器的亮度信号,亮度信号的高频分量和色度信号被混合以获得复合彩色视频信号。