System and method for eliminating audible noise for ultrasonic transducers
AssigneeAutomotive Technologies International, Inc.
InventorsDavid S. Breed, Wilbur E. DuVall, Wendell C. Johnson
Life of this patent
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Abstract
Methods for reducing clicking of ultrasonic air-coupled transducers in which a mechanical filter that attenuates audible frequencies relative to ultrasonic frequencies is placed in the path of the ultrasonic waves as the travel from the transducer to a target such as an object in the vehicle compartment.
Claims20
A method for producing ultrasonic sound waves with an ultrasonic transducer to realize reduced audible noise, the method comprising the steps of:
- arranging a filter which attenuates low frequencies to a greater extent than higher frequencies in front of the ultrasonic transducer;
- and
- applying a transducer drive signal as input to the ultrasonic transducer to produce ultrasonic sound waves which pass through the filter and provide filtered ultrasonic sound waves with reduced audible noise effects.
A method for producing ultrasonic sound waves with an ultrasonic transducer to realize reduced audible noise, the method comprising the steps of:
- arranging a filter that selectively attenuates audio frequencies relative to ultrasonic frequencies in front of the ultrasonic transducer;
- and
- applying a transducer drive signal as input to the ultrasonic transducer to produce ultrasonic sound waves which pass through the filter and provide filtered ultrasonic sound waves with reduced audible noise effects.
An ultrasonic ranging system, comprising:
- an ultrasonic transducer for generating ultrasonic sound waves and transmitting the ultrasonic sound waves in a transmission path, said ultrasonic transducer being arranged to receive ultrasonic sound waves reflected from a target in the transmission path and converting the received reflected sound waves to an electrical signal;
- a filter for selectively filtering audible frequencies relative to ultrasonic frequencies, said filter being arranged in front of said ultrasonic transducer in the transmission path;
- and
- a processor coupled to said ultrasonic transducer for processing the electrical signal from said ultrasonic transducer into time and distance information to the target.
A vehicle including an ultrasonic ranging system, comprising:
- an ultrasonic transducer for generating ultrasonic sound waves and transmitting the ultrasonic sound waves in a transmission path, said ultrasonic transducer being arranged to receive ultrasonic sound waves reflected from an object in an interior compartment of the vehicle in the transmission path and converting the received reflected sound waves to an electrical signal;
- a filter for selectively filtering audible frequencies relative to ultrasonic frequencies, said filter being arranged in front of said ultrasonic transducer in the transmission path;
- and
- a processor coupled to said ultrasonic transducer for processing the electrical signal from said ultrasonic transducer into time and distance information to the object.
Dependencies are inferred from the claim text.