BALLANCE ADJUSTING APPARATUS FOR PHOTO-DETECTOR FOR TRACKING ERROR DETECTING

摘要

An improved balance adjustment device that does not require a low pass filter to calculate an average value of a tracking error signal.;The balance adjusting device according to the present invention comprises: two amplifiers each amplifying two optical output signals generated from a two-segment photodetector; A subtractor for subtracting the outputs of the amplifiers from each other; A comparator for comparing the output of the subtractor with a predetermined reference voltage and outputting the result as a digital signal; And a controller for controlling the amplification gain of the amplifier based on the time difference between the two states in the digital signal provided from the comparator.;The balance adjusting device according to the present invention calculates the average value of the tracking error signal by a comparator and a counter, and thus does not require a low pass filter as in the prior art. Therefore, the RC time constant circuit and the procedure for adjusting the same do not need to have the effect of improving the productivity of the product.