| 摘要 |
PURPOSE:To amplify only the plus side of a necessary signal to remove an unnecessary signal component by providing a comparator which inputs the output signal of a sensor and its phase-inverted signal and a charging and discharging circuit between its plus input terminal and the ground. CONSTITUTION:Opposite-phase signals (a) and (b) from the magnetic sensor are supplied to the minus and plus input terminals of the comparator 10. The charging and discharging circuit consisting of a capacitor C1 and a resistance R1 and a transistor (TR) T1 connected in parallel thereto are provided between the plus input terminal of the comparator 10 and the ground. The capacitor C1 is charged by the minus side of the signal (a), i.e. the plus side of the signal (b) and discharged gradually through the resistance R1. The TR, T1 is turned on by the plus side of the signal (a) to discharge the capacitor C1 completely. Consequently, the plus terminal of the comparator 10 is held at some potential after the charging and the potential is invariably higher than that of an unnecessary waveform arriving at the minus terminal, thus amplifying only the plus side of the necessary signal (a). |
