公开(公告)号：US4823330A

公开(公告)日：1989-04-18

申请号：US52128

申请日：1987-05-04

申请人： Nelson K. Arter ,  Mark G. Call ,  Mark L. Rhoades

发明人： Nelson K. Arter ,  Mark G. Call ,  Mark L. Rhoades

IPC分类号： G11B7/09 ,  G11B7/12

CPC分类号： G11B7/094 ,  G11B7/0945 ,  G11B2007/0919 ,  G11B7/0909

摘要： Error compensation in a feedback servo system. The feedback servo loop in, for example, a head positioning circuit in an optical disk data recording and retrieval system is provided with a compensation signal to correct for misalignment or other errors. The head in such a system must be dynamically maintained at a best focus position but, through use and transporting, the alignment of the head position error detecting system can be disturbed. In some cases, the loop circuit parameters may drift from their original values. To correct for errors introduced from such causes, the head is positioned at best focus and the focus error (head position error) signal is sensed. A correction signal is supplied which cancels out the sensed value while the system is operating.

摘要翻译： 反馈伺服系统中的误差补偿。 在例如光盘数据记录和检索系统中的头定位电路中的反馈伺服环路被提供有补偿信号以校正未对准或其他错误。 这种系统中的头部必须被动态地保持在最佳对焦位置，但是通过使用和传送，头部位置误差检测系统的对准可能受到干扰。 在某些情况下，环路电路参数可能偏离其原始值。 为了纠正从这些原因引起的错误，头部被定位在最佳焦点处，并且感测到聚焦误差（头位置误差）信号。 提供校正信号，其在系统运行时消除感测值。

公开(公告)号：US4881076A

公开(公告)日：1989-11-14

申请号：US126653

申请日：1987-12-01

申请人： Jonathan J. Ashley ,  Mark G. Call ,  Paul H. Siegel

发明人： Jonathan J. Ashley ,  Mark G. Call ,  Paul H. Siegel

IPC分类号： H03M7/46 ,  G11B20/14 ,  H03M7/14

CPC分类号： G11B20/1426

摘要： Encoding method for data to be recorded on optical disks using the pit-per-transition technique or return-to-zero techniques whereby the characteristics of the encoded bits produce a stable, low frequency spectral notch and minimum interference with associated focus and tracking servomechanisms. RLL (d,k) code words are selected so that the ratio of the lengths of pits and lands approximate some nonzero fraction less than one-half which depends on the (d,k) code employed. For example, a fraction of 1/3 is appropriate for RLL (2,7).

公开(公告)号：US4494080A

公开(公告)日：1985-01-15

申请号：US321508

申请日：1981-11-16

申请人： Mark G. Call

发明人： Mark G. Call

IPC分类号： H03K3/282 ,  H03L7/099 ,  H03L7/10 ,  H03K3/03 ,  H03J7/04

CPC分类号： H03L7/099

摘要： A voltage-controlled oscillator (VCO) comprises a current controlled oscillator (ICO) and control circuitry which independently adjusts the gain (K.sub.v) and free-run or center frequency of the VCO. The control circuitry includes a first current source selected to set the free-run frequency of the VCO and a second current source selected to set the gain (K.sub.v) of the VCO. The current sources are coupled to a common node in a summing/difference configuration. The controlled current generated from the summing/difference configuration is delivered into the ICO. Independent current mirrors are utilized to supply controlled current into the node of the summing/difference configuration.

摘要翻译： 压控振荡器（VCO）包括电流控制振荡器（ICO）和控制电路，其独立地调节VCO的增益（Kv）和自由运行或中心频率。 控制电路包括被选择用于设置VCO的自由运行频率的第一电流源和被选择用于设置VCO的增益（Kv）的第二电流源。 电流源以总和/差分配置耦合到公共节点。 从求和/差分配置产生的受控电流传送到ICO。 利用独立电流镜将受控电流提供给求和/差分配置的节点。