| 摘要 |
PROBLEM TO BE SOLVED: To unnecessitate the manual adjusting operation for the waveform of an output signal from plural photodetectors by providing a processing circuit which receives an output signal from plural photodetectors for a carriage position detection and processes the waveform of the output signal to be in a prescribed voltage range. SOLUTION: A subtraction amplifier circuit 1, receiving the output signal PT0-PT3 of an amplitude PT0-PT3 from four detection phototransistors for the carriage position detection, calculates X1×(PT0-PT2)+Y1 and X2×(PT 1-PT3)+Y2. A digital signal processing circuit 4 determines an arithmetic coefficient X1, X2, Y1, Y2 necessary for the waveform of the output signal PT0-PT3 to be in a prescribed range, and outputs the subtraction amplifier circuit 1 through an analog switch 2, D/A converter 3. Consequently, a manual adjusting operation is unnecessitated that is for the output signal from the phototransistors, enabling automatic correction against change in a signal waveform through secular deterioration.
|
