| 摘要 |
<p>PURPOSE:To obtain a vehicle borne ultrasonic sensor which can simulteneously and highly accurately detect existence of protrusives and steps. CONSTITUTION:The sensor of this invention is provided with a transmitter/ receiver 2, a protrusives detection circuit 8 and a step detection circuit 9. The transmitter/receiver transmits first wide ultrasonic bursts and second short ultrasonic burst alternatively, and also receives reflected waves. The protrusives detection circuit 8 is turned on in response to a reflected wave at a high level and with substantially the same width as the first burst. The step detection circuit 9 is turned on in response to zero input between low-level signals. The protrusives detection circuit 8 turns into a detecting condition upon sending the first burst, while the step detection circuit 9 turns into a detecting condition upon sending the second burst.</p> |
