| 摘要 |
PURPOSE:To prevent an operation error due to a static body, by processing a signal so that an output of H level and an output of L level can be obtained when there is a moving body in a detection set distance, and when there is a static body only, respectively. CONSTITUTION:When an ultrasonic output is made to oscillate from the oscillator 4, its output passes 5 during the on period of the input gate 3, and it is radiated from the transmitter 7. An ultrasonic wave which has been radiated is reflected by the body, is received by the receiver 8, and an output which passes only the on time of the gate 3 is obtained by the switch 10. On the other hand, the oscillating output which has been controlled by the switch 5 is mixed 11 with the receiving signal, and is detected 12. This detected output is provided to the AND circuit 18 through the band amplifier 13, the level comparator 14 and the integrating circuit 15. Also, the AND 16 output of the distance gate 2 and the input gate 3 is differentiated 17, becomes a signal processing start signal, and is provided to the circuit 18. Accordingly, when there is a moving body within a detection set distance from the circuit 18, and when there is a static body only, an output of H level and an output of L level are obtained, respectively, and they are provided to the FF19. |
