Patent ID: 8254221

Claim:
A circuit for generating a tracking error signal, the circuit outputs the tracking error signal according to a first pick-up signal, a second pick-up signal, a third pick-up signal and a fourth pick-up signal respectively representing reflected intensities of a main beam measured by a first light detecting element, a second light detecting element, a third light detecting element and fourth light detecting element of a pick-up head, the circuit comprising: a first adding circuit, for adding the first pick-up signal and the second pick-up signal, so as to obtain a first adding signal; a second adding circuit, for adding the third pick-up signal and the fourth pick-up signal, so as to obtain a second adding signal; a digitizing circuit, for respectively comparing the first adding signal and the second adding signal with a reference voltage, so as to obtain a first digital signal and a second digital signal; a short signal removing circuit, for respectively removing pulses in the first digital signal and the second digital signal to generate a first determining signal and a second determining signal, when the pulse width of the removed pulses are shorter than a preset time, wherein the short signal removing circuit is implemented using a pure digital logic circuit; and a phase comparator, for outputting the tracking error signal according to a phase difference between the first determining signal and the second determining signal.