| 摘要 |
PURPOSE:To prevent erroneous warning generation due to an external noise by deciding that only when received wave outputs for reflected waves of two latched ultrasonic waves, etc., coincide with each other, the received wave outputs are discriminated as obstruction detection outputs. CONSTITUTION:The 1st and the 2nd signal latch circuits 10 and 11 controlled by the 1st latch pulse generating circuit 9 latch successively received wave signals from a receiver 3, etc., for ultrasonic waves, etc., reflected by an obstacle. When latch contents of the circuits 10 and 11 coincide with each other, it is decided that they are a reflected wave from the obstacle, and the 2nd latch pulse generating circuit 1 is driven in response to the output of a coincidence deciding circuit 12; and the 3rd signal latch circuit 14 latches the latch contents of the circuit 10 and the warning of collision prevention, etc. is generated through a warning circuit 8. This constitution prevents erroneous warning generation due to an external noise. |
