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OPTICAL INFORMATION CARRIER, OPTICAL DEVICE FOR GENERATING TRACKING SIGNALS AND OPTICAL DEVICE FOR GENERATING ERROR SIGNALS FOR FOCUSSING
OPTICAL INFORMATION CARRIER, OPTICAL DEVICE FOR GENERATING TRACKING SIGNALS AND OPTICAL DEVICE FOR GENERATING ERROR SIGNALS FOR FOCUSSING
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机译:光学信息载体,用于生成跟踪信号的光学装置以及用于生成用于聚焦的错误信号的光学装置
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摘要
The process makes it possible to generate on the basis of discrete preetching elements or flags, the radial tracking error and/or focusing error signals. The flags comprise portions displaced with respect to the mean axis of the tracks to be followed. According to a first variant, each track comprises portions displaced on either side of the axis. According to a second variant the flags comprise portions alternately displaced to one and then the other side thereof. In response to the passages of these portions, windows are generated and the pulses supplied by the photodetectors of the interaction of these portions on the focused scan beam are compared between successive windows.
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