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公开(公告)号：US5583706A
公开(公告)日：1996-12-10
申请号：US341723
申请日：1994-11-17
CPC分类号： G11B20/10055 , G11B20/10009 , G11B20/10037 , G11B20/1403 , G11B19/04
摘要： In a sampled amplitude read channel for magnetic recording, a nonlinear discrete time decimation filter in a negative feed back loop adjusts a DC offset in an analog read signal from a magnetic read head without distorting the read signal. In sampled amplitude recording, adding the samples of an isolated positive pulse to the samples of an isolated negative pulse generates the DC offset of the discrete time sample values. A decimation filter adds the sample values from a positive pulse to the sample values of a negative pulse in order to detect and pass the DC offset in the read signal. The detected discrete time DC offset from the discrete time decimation filter is converted into an analog DC offset signal and subtracted from the analog read signal in a negative feedback loop. A running average decimation filter removes the DC offset during acquisition, and a decision-directed decimation filter removes the DC offset during tracking.
摘要翻译： 在用于磁记录的采样幅度读取通道中，负反馈回路中的非线性离散时间抽取滤波器调整来自磁读头的模拟读取信号中的DC偏移，而不会使读取信号失真。 在采样振幅记录中，将隔离的正脉冲的样本加到分离的负脉冲的采样中，产生离散时间采样值的直流偏移。 抽取滤波器将来自正脉冲的采样值与负脉冲的采样值相加，以便检测并通过读信号中的直流偏移。 从离散时间抽取滤波器检测到的离散时间直流偏移被转换为模拟直流偏移信号，并从负反馈回路中的模拟读取信号中减去。 运行平均抽取滤波器在采集期间去除DC偏移，并且决策导频抽取滤波器在跟踪期间去除DC偏移。
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2.发明授权Detecting servo data and servo bursts from discrete time samples of an analog read signal in a sampled amplitude read channel 有权在采样振幅读通道中从模拟读信号的离散时间采样中检测伺服数据和伺服脉冲串
公开(公告)号：US6144513A
公开(公告)日：2000-11-07
申请号：US166598
申请日：1998-09-28
CPC分类号： G11B21/083 , G11B21/085 , G11B21/106 , G11B5/59655 , G11B5/59688 , G11B20/10037 , G11B20/10055
摘要： A discrete time servo demodulation technique incorporated within a sampled amplitude read channel to demodulate embedded servo field information stored on a magnetic medium. The servo field information is transduced by a read head into an analog signal, and converted to a sequence of sample values in the read channel. The demodulation technique is responsive to the sample values and includes a discrete time peak detector for detecting servo data, and a discrete time servo burst amplitude detector for measuring the amplitude of servo bursts. Peaks are detected in the analog read signal by sensing a change of slope from the sequence of sample values. The peaks are qualified by polarity in that a peak is detected only if its polarity is opposite in sign from the previous peak. The servo burst amplitudes are measured by interpolating, rectifying, and accumulating the sequence of sample values corresponding to the servo bursts. A plurality of registers store the amplitude measurement of corresponding servo bursts such as the four servo bursts in a quadrature system. The sample values are interpolated, squared, and the sampling frequency dithered in order to decrease the sensitivity of the burst amplitude measurement to variations in the sampling phase and to increase the effective resolution of the read channel ADC for servo demodulation. Control signals are generated in response to the detected servo data which are transferred to a servo controller over a fully digital interface, thus obviating the analog-to-digital converter found in conventional servo controllers.
摘要翻译： 一种并入采样振幅读通道内的离散时间伺服解调技术，用于解调存储在磁介质上的嵌入式伺服场信息。 伺服字段信息由读取头转换为模拟信号，并转换为读通道中的一系列采样值。 解调技术响应于采样值，并且包括用于检测伺服数据的离散时间峰值检测器和用于测量伺服脉冲串幅度的离散时间伺服脉冲串幅度检测器。 通过从样本值序列感测斜率的变化，在模拟读取信号中检测峰。 峰由极性限定，只有当峰的极性与前一峰的符号相反时才检测到峰。 通过内插，整流和累加对应于伺服脉冲串的采样值序列来测量伺服脉冲串幅度。 多个寄存器将相应伺服脉冲串的振幅测量值存储在正交系统中，例如四个伺服脉冲串。 样本值被内插，平方，并且采样频率抖动，以便将脉冲串幅度测量的灵敏度降低到采样相位的变化并且增加用于伺服解调的读通道ADC的有效分辨率。 响应于通过全数字接口传送到伺服控制器的检测到的伺服数据产生控制信号，从而避免了在常规伺服控制器中发现的模拟 - 数字转换器。
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