Self-tuning acoustic measurement system
First Claim
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1. A method of forming a distance measurement circuit, comprising:
- configuring the distance measurement circuit to form a driving signal to drive an ultrasonic transducer;
configuring the distance measurement circuit to substantially cease the driving signal;
configuring the distance measurement circuit to receive a resonant signal, having a present resonant frequency, produced by the ultrasonic transducer during a reverberation period in response to ceasing the driving signal;
configuring the distance measurement circuit to determine the present resonant frequency of the resonant signal from only one occurrence of the driving signal;
configuring the distance measurement circuit to tune a measurement frequency of the distance measurement circuit to a frequency within a predefined bandwidth of the present resonant frequency; and
configuring the distance measurement circuit to form a measurement signal at the measurement frequency.
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Abstract
In one embodiment, an acoustic distance measurement system can dynamically adjust its measurement frequency to a frequency that is within a preselected bandwidth of the resonant frequency of an acoustic transducer used in making acoustic distance measurements.
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Citations
20 Claims
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1. A method of forming a distance measurement circuit, comprising:
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configuring the distance measurement circuit to form a driving signal to drive an ultrasonic transducer; configuring the distance measurement circuit to substantially cease the driving signal; configuring the distance measurement circuit to receive a resonant signal, having a present resonant frequency, produced by the ultrasonic transducer during a reverberation period in response to ceasing the driving signal; configuring the distance measurement circuit to determine the present resonant frequency of the resonant signal from only one occurrence of the driving signal; configuring the distance measurement circuit to tune a measurement frequency of the distance measurement circuit to a frequency within a predefined bandwidth of the present resonant frequency; and configuring the distance measurement circuit to form a measurement signal at the measurement frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A self-tuning acoustic distance measurement circuit, comprising:
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a driving circuit which generates a driving signal having a measurement frequency used for an acoustic distance measurement operation, and is configured to selectively provide the driving signal to an acoustic transducer and to cease the driving signal during the distance measurement operation; a frequency determination circuit which, during the distance measurement operation, based on only one occurrence of the driving signal, determines a resonant frequency from a resonant signal produced by the acoustic transducer during a reverberation period that occurs immediately after the driving circuit ceases the driving signal, and wherein the frequency determination circuit further indicates the resonant frequency to the driving circuit; and wherein the driving circuit, in response to determining the resonant frequency, adjusts the measurement frequency to a frequency within a preselected bandwidth of the resonant frequency. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A distance measurement circuit for conducting ultrasonic distance measurements, comprising:
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an ultrasonic transmitter, including; a tunable oscillator which generates an oscillator signal at a selected driving frequency; and a signal generator coupled to the tunable oscillator and which generates a driving signal from the oscillator signal by pulsing the oscillator signal between selected start and stop times, wherein the driving signal is operable to cause an ultrasonic transducer to produce a resonant signal at a resonant frequency during a reverberation period responsive to the driving signal being stopped; an ultrasonic receiver, including; a signal processor operable to receive the resonant signal from the ultrasonic transducer during the reverberation period and produce a frequency information signal based on the resonant signal; and a frequency processor coupled to the signal processor that, based on only one occurrence of the driving signal, determines the resonant frequency from the frequency information signal and indicates the resonant frequency to the ultrasonic transmitter; wherein the ultrasonic transmitter adjusts the tunable oscillator to maintain the selected driving frequency within a preselected bandwidth of the resonant frequency. - View Dependent Claims (18, 19, 20)
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Specification