| 摘要 |
<p>PURPOSE:To make it possible to complete the detection of an object over a wide range within a short time, by setting a control signal to an ON-level simultaneously with the emission of a signal such as an ultrasonic wave to continuously change the amplifying degree of an amplifier for a receiving signal according to an index function curve. CONSTITUTION:A control signal CRTL comes to L being an ON-level simultaneously with the emission of a signal such as an ultrasonic wave and the transistor Qe of the scanning signal generation circuit 83b of a function generation circuit 83 is turned OFF and, by a constant current through an operational amplifier OP2, a Zener diode 2D and a variable resistor VR2, a capacitor C5 discharged at the H-time of the signal CTRL is charged. The charge voltage of said capacitor C5 is supplied through a non-linear signal processing circuit 83a and the amplifying degree of an amplifying circuit 82, to which an ultrasonic reflected receiving signal is applied from a terminal IN, continuously changes according to index function. Therefore, the receiving signal corresponding to a distance successively changed over and inputted comes to a constant value through the circuit 82 regardless of a distance and a wide range of the objects is certainly detected within a short time by one measurement.</p> |
