MEMS-based audio speaker system using single sideband modulation
First Claim
1. A speaker apparatus, comprising:
- a first speaker device that comprises;
a first oscillation element configured to generate a first ultrasonic acoustic signal along a first directional path; and
a second oscillation element configured to modulate the first ultrasonic acoustic signal such that a first acoustic signal is generated; and
a second speaker device that comprises;
a third oscillation element configured to generate a second ultrasonic acoustic signal along the first directional path; and
a fourth oscillation element configured to modulate the second ultrasonic acoustic signal such that a second acoustic signal is generated, wherein the second acoustic signal is a linear derivation of the first acoustic signal and is a different acoustic signal than the first acoustic signal, andwherein the first speaker device and the second speaker device are each contained in a volume with at least one dimension of unit smaller than a wavelength of the first ultrasonic acoustic signal.
3 Assignments
0 Petitions
Accused Products
Abstract
Techniques described herein generally include methods and systems related to a MEMS-based audio speaker system configured with multiple speaker devices to generate an audio signal that is substantially without a high-band ultrasonic signal. Energy may be transferred to a low frequency sideband of the audio signal output and substantially eliminated from the high frequency sideband of the audio signal by passing an acoustic carrier signal through two different modulators. One modulator may implement a first modulation function on the acoustic carrier signal to generate a first audio signal, where the first modulation function may be based on a target acoustic output signal for the MEMS-based audio speaker system. The second modulator may implement a second modulation function on the acoustic carrier signal to generate a second audio signal, where the second audio signal may be the Hilbert transform of the first audio signal.
-
Citations
26 Claims
-
1. A speaker apparatus, comprising:
-
a first speaker device that comprises; a first oscillation element configured to generate a first ultrasonic acoustic signal along a first directional path; and a second oscillation element configured to modulate the first ultrasonic acoustic signal such that a first acoustic signal is generated; and a second speaker device that comprises; a third oscillation element configured to generate a second ultrasonic acoustic signal along the first directional path; and a fourth oscillation element configured to modulate the second ultrasonic acoustic signal such that a second acoustic signal is generated, wherein the second acoustic signal is a linear derivation of the first acoustic signal and is a different acoustic signal than the first acoustic signal, and wherein the first speaker device and the second speaker device are each contained in a volume with at least one dimension of unit smaller than a wavelength of the first ultrasonic acoustic signal. - View Dependent Claims (2, 3, 4, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
- 5. The speaker apparatus of cl aim 4, wherein the controller is configured to offset a phase of the first acoustic signal relative to a phase of the second acoustic signal and to alter an amplitude of the first acoustic signal relative to an amplitude of the second acoustic signal to generate the acoustic directionality of the resultant acoustic signal.
-
25. A method to generate an acoustic signal with a microelectromechanical system (MEMS) structure-based audio speaker that includes a first speaker device and a second speaker device which are configured to emit the acoustic signal from a same location, the method comprising:
- displacing an oscillation element of the first speaker device by use of a first modulation function to generate a first acoustic signal; and
displacing an oscillation element of the second speaker device by use of a second modulation function to generate a second acoustic signal, wherein the second modulation function comprises a Hilbert transform of the first modulation function;
generating an ultrasonic acoustic signal that is directed toward the oscillation element of the first speaker device and the oscillation element of the second speaker device; and
wherein the first speaker device and the second speaker device are each contained in a volume with at least one dimension of unit smaller than a wavelength of the first ultrasonic acoustic signal. - View Dependent Claims (26)
- displacing an oscillation element of the first speaker device by use of a first modulation function to generate a first acoustic signal; and
Specification