| 摘要 |
Disclosed is an apparatus to detect a tracking error signal although the phase difference between E, F signals is - 180 degree. The apparatus comprises the first operational amplifier(A1), the second operational amplifier(A2), the first switch(SW1), the second switch(SW2) and a switching controller(10). The first operational amplifier(A1) operates the E signal of (-) input and F signal of (+) input to detect a tracking error signal. The second operational amplifier(A2) operates the E signal of (+) input and F signal of (-) input to detect a tracking error signal. The first switch(SW1) controls the path of E signal to the first and second amplifiers(A1, A2). The second switch(SW2) controls the path of F signal to the first and second amplifiers(A1, A2). The switching controller(10) controls the first and second switches(SW1, SW2) according to the phase difference between the E and F signals. Thereby, it is possible to detect the tracking error signal although the phase difference between E, F signals is - 180.
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