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2019
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Invention
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Ultrasonic sensor element having improved performance. The present invention provides an ultrason... |
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2018
|
Invention
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Improved ultrasound super-directional speaker system and frequency modulation processing method t... |
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|
Invention
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Ultra-directional speaker circuit with enhanced stability. The present invention relates to an ul... |
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2017
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Invention
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Complex speaker system capable of simultaneously outputting ultra-directional and non-directional... |
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2016
|
Invention
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Tunnel information broadcasting system using speakers for tunnel that have an improved ability to... |
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Invention
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Information providing system using ultrasonic speaker transmitting differential signal. The prese... |
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Invention
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Information provision system using ultrasonic speaker. The present invention provides an informat... |
