公开(公告)号：JPH02179416A

公开(公告)日：1990-07-12

申请号：JP27698189

申请日：1989-10-24

Applicant: MARELLI AUTRONICA

Inventor： DEIEGO RAZAANIYA ,  FURANSESUKO SEMERARO

IPC: G01B7/30 ,  G01B7/00 ,  G01D5/244 ,  G01D5/245 ,  G01R19/175 ,  H03K5/1536

Abstract: PURPOSE: To detect a low peak signal by providing a circuit for resetting an accumulation means so that the means reaches 0 every time when a signal generated by a sensor exceeds a threshold signal. CONSTITUTION: When a rotor 2 rotates, a voltage signal Vi is outputted from a pickup 4 every time when a gear 3 passes the front of the pickup 4, and the signal Vi is supplied to a clamp circuit 6 via a resistor 5. Then, an output signal Ve from the circuit 6 is inputted to a threshold comparison circuit 7 and a threshold signal generation circuit 8. A threshold signal Vs is outputted to the comparator 7 from the circuit 8. In the comparator 7, its output signal Vo is changed from high to low levels when the signal Ve exceeds a signal Vs. The signal Vo operates a monostable circuit 14, and the circuit 14 switches a switch 12 into conduction state for a predetermined time. Therefore, a capacitor 11 momentarily discharges through the switch 12. Then, when the characteristic time of the circuit 14 passes, the switch 12 is changed to a nonconduction state, and the capacitor 11 is charged to a new peak voltage of the signal Ve.