麻省理工大学公开课
南师大自考>采矿工程考研died专利名称：ULTRASONIC DETECTOR 发明人：SASAKI HAJIME
申请号：JP16464790
申请日：19900621
横亘公开号：JPH0454480A
公开日：lfl
介词短语
19920221
save me专利内容由知识产权出版社提供
fow摘要：PURPOSE:To improve the conversion efficiency at the time of wave transmission by switching the impedance of a transmitter receiver in a wave transmission period to low impedance. CONSTITUTION:A microcomputer 1 outputs a signal of t frequency f1 to a transmitting amplifier 2 for a period T1 and the signal is amplified and then outputted to a microphone 3. The microcomputer 1 outputs a control signal of L to a transistor(TR) Q1 through a resistance R1 for the period T1 and the TR Q1 turns off. Conquently, the microphone 3 nds a wave with impedance Z1 corresponding to the frequency f1. The control signal from the microcomputer 1 to the TR Q1 is inverted from L to H the period T1 later and the TR Q1 turns on to connects a capacitor C1 to the microphone 3 in parallel. The microphone 3 receives a reflected wave from a target, etc., with impedance Z2. A received signal after a reverberation period is detected to judge whether or not there is the target, etc.
申请人：MATSUSHITA ELECTRIC WORKS LTDlastchristmas
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