Parametric audio system
First Claim
1. A method of broadening a frequency response of an acoustic transducer array, comprising the steps of:
- providing an acoustic transducer array including a backplate having a surface and a series of depressions formed on the surface, and a membrane with at least one conductive surface disposed adjacent the backplate, wherein the respective depressions have one or more variable dimensions, wherein the membrane and the series of depressions define a plurality of acoustic transducers, and wherein the plurality of acoustic transducers have a plurality of associated center frequencies, respectively, the plurality of associated center frequencies being determined at least in part by the variable dimensions of the respective depressions;
for each of at least some of the plurality of acoustic transducers, determining the center frequencies of the respective acoustic transducers, including setting the variable dimensions of the respective depressions such that the plurality acoustic transducers define by the membrane and the series of depressions include at least one first acoustic transducer having at least one first specified center frequency followed by at least one second acoustic transducer having at least one second specified center frequency; and
spacing the at least one first specified center frequency of the at least one first acoustic transducer and the at least one second specified center frequency of the at least one second acoustic transducer apart to span a predetermined frequency range, thereby broadening the frequency response of the acoustic transducer array.
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Abstract
A parametric audio system having increased bandwidth for generating airborne audio signals with reduced distortion. The parametric audio system includes a modulator for modulating an ultrasonic carrier signal with a processed audio signal, a driver amplifier for amplifying the modulated carrier signal, and an array of acoustic transducers for projecting the modulated and amplified carrier signal through the air along a selected projection path to regenerate the audio signal. The acoustic transducer array includes a backplate having a succession of depressions formed thereon with at least one varying feature and/or dimension, and a membrane disposed along the backplate. The feature and/or dimension of the respective depressions vary so that the center frequencies of the respective acoustic transducers span a desired frequency range, thereby broadening the frequency response of the acoustic transducer array.
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Citations
32 Claims
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1. A method of broadening a frequency response of an acoustic transducer array, comprising the steps of:
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providing an acoustic transducer array including a backplate having a surface and a series of depressions formed on the surface, and a membrane with at least one conductive surface disposed adjacent the backplate, wherein the respective depressions have one or more variable dimensions, wherein the membrane and the series of depressions define a plurality of acoustic transducers, and wherein the plurality of acoustic transducers have a plurality of associated center frequencies, respectively, the plurality of associated center frequencies being determined at least in part by the variable dimensions of the respective depressions; for each of at least some of the plurality of acoustic transducers, determining the center frequencies of the respective acoustic transducers, including setting the variable dimensions of the respective depressions such that the plurality acoustic transducers define by the membrane and the series of depressions include at least one first acoustic transducer having at least one first specified center frequency followed by at least one second acoustic transducer having at least one second specified center frequency; and spacing the at least one first specified center frequency of the at least one first acoustic transducer and the at least one second specified center frequency of the at least one second acoustic transducer apart to span a predetermined frequency range, thereby broadening the frequency response of the acoustic transducer array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of broadening a frequency response of an acoustic transducer array, comprising the steps of:
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providing an acoustic transducer array including a backplate having a surface and a series of holes formed on the surface, and a membrane with at least one conductive surface disposed adjacent the backplate, wherein the respective holes have at least one variable dimension, and wherein the membrane and the series of holes define a plurality of acoustic transducers, each of the plurality of acoustic transducers having an associated center frequency, the associated center frequency being determined at least in part by the variable dimension of a respective depression; for each of at least some of the plurality of acoustic transducers, determining the center frequency of the respective acoustic transducer by setting the variable dimension of the hole associated with the respective acoustic transducer such that the plurality acoustic transducers defined by the membrane and the series of depressions include at least one first acoustic transducer having at least one first specified center frequency followed by at least one second acoustic transducer having at least one second specified center frequency; and spacing the at least one first specified center frequency of the at least one first acoustic transducer and the at least one second specified center frequency of the at least one second acoustic transducer apart to span a predetermined frequency range, thereby broadening the frequency response of the acoustic transducer array. - View Dependent Claims (14, 15)
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16. An acoustic transducer array, comprising:
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a backplate having a surface and a series of depressions formed on the surface; and a membrane with at least one conductive surface disposed adjacent the backplate, wherein the respective depressions have at least one variable dimension, wherein the membrane and the series of depressions define a plurality of acoustic transducers, each of the plurality of acoustic transducers having an associated center frequency, the associated center frequency being determined at least in part by the variable dimension of a respective depression, wherein, for each of at least some of the plurality of acoustic transducers, the center frequency of the respective acoustic transducer is determined by a setting of the variable dimension of the depression associated with the respective acoustic transducer such that the plurality acoustic transducers defined by the membrane and the series of depressions include at least one first acoustic transducer having at least one first specified center frequency followed by at least one second acoustic transducer having at least one second specified center frequency, and wherein the at least one first specified center frequency of the at least one first acoustic transducer and the at least one second specified center frequency of the at least one second acoustic transducer are spaced apart to span a predetermined frequency range, thereby broadening a frequency response of the acoustic transducer array. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification