Abstract: A data phase locked loop circuit includes a phase locked loop circuit, a judging circuit, a detecting circuit and a control circuit. The phase locked loop circuit outputs a reference signal according to a data signal, which is generated by an optical drive reading an optical disk. When the judging circuit judges that a jitter signal is smaller than a threshold value, the control circuit stores a frequency of the reference signal. When the detecting circuit detects a defect zone of the optical disk read by the optical drive, the phase locked loop circuit fixes the frequency of the reference signal to a latest stored one.

Abstract: An encryption/decryption method and devices for protecting data in a memory device from unauthorized access is provided. First, obtaining a specific code from a memory device and then encrypting the specific code and original data for obtaining encrypted data during a write cycle. Finally, writing the encrypted data to the memory device according to an access address. The access address can be also encrypted to generate the encrypted data. The encryption level increases by this way so that the valuable information is under protection.

Abstract: A data phase locked loop circuit includes a phase locked loop circuit, a judging circuit, a detecting circuit and a control circuit. The phase locked loop circuit outputs a reference signal according to a data signal, which is generated by an optical drive reading an optical disk. When the judging circuit judges that a jitter signal is smaller than a threshold value, the control circuit stores a frequency of the reference signal. When the detecting circuit detects a defect zone of the optical disk read by the optical drive, the phase locked loop circuit fixes the frequency of the reference signal to a latest stored one.

Abstract: An encryption/decryption method and devices for protecting data in a memory device from unauthorized access is provided. First, obtaining a specific code from a memory device and then encrypting the specific code and original data for obtaining encrypted data during a write cycle. Finally, writing the encrypted data to the memory device according to an access address. The access address can be also encrypted to generate the encrypted data. The encryption level increases by this way so that the valuable information is under protection.