摘要 |
A method of detecting an abnormal disc is provided. Firstly, an objective lens is moved along a one-way path for enabling the light beam of the objective lens to pass through the data layer of a disc. Next, the path having RF signal is detected and recorded. Then, whether the terminal of the one-way path is reached is determined: if the terminal is not reached, the method continues to move the objective lens; if the terminal is reached, the method calculates the length of vibration path on which RF signal is detected. After that, whether the length of vibration path is larger than a path threshold is determined: if the length of vibration path is not larger than a path threshold, the disc is a normal disc; if the length of vibration path is larger than the path threshold, the disc is an abnormal disc.
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