The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 30, 1987
Filed:
Jun. 19, 1985
Hiroaki Obayashi, Yokosuka, JP;
Hiroshi Kobayashi, Yokohama, JP;
Nissan Motor Company, Limited, Kanagawa, JP;
Abstract
An ultra-sonic sensor includes a driver circuit outputting a high-frequency driver signal which orders a transmitter to transmit ultra-sonic waves toward a target object. The driver circuit also sends the driver signal to a receiver. The driver signal is superimposed on a receiver signal. The receiver differentiates the receiver signal and compares the differentiated receiver signal level to a threshold level to detect reception of the reflected ultra-sonic wave. The receiver also detects when the transmitter is actively transmitting the ultra-sonic waves toward the object and disables the aforementioned comparison at such times. Accordingly, by comparing the differentiated receiver signal level with the threshold, the influence directly transmitted ultra-sonic waves on detection of the reflected ultra-sonic wave is successfully avoided. In addition, by interrupting the comparison during a period in which the transmitter is transmitting the ultra-sonic waves, the threshold level can be low enough to allow the system to detect the reflected ultra-sonic wave with great sensitivity.