Uses invasion body detection manner and this manner which use the ultra wave the ultrasonic sensor

摘要

PURPOSE: To permit the sampling of the correct standard data by starting or suspending the sampling processing for the standard data when the noise level is below a prescribed level or exceeds the prescribed level. ;CONSTITUTION: When, in a noise level comparison circuit 11, it is judged that the noise signal level included in a received signal after decoding exceeds a prescribed level, it is considered that the normal sampling is impossible because of the external noise, and a judging signal is transmitted to a gate circuit 10, and the output of the transmission gate signal and the received wave gate signal is suspended, and the sampling of the standard data is suspended. While, when the circuit 11 judges that the noise signal level does not exceed the prescribed level, a transmitter T transmits ultrasonic waves through the transmission gate subsequently to the noise sampling gate signal, and the reflection wave is received by a receiving device R, and the signal which is decoded for the wave receiving period is stored as standard data in a memory circuit 108 in the order of time sequence.;COPYRIGHT: (C)1993,JPO&Japio