Abstract: The present invention relates to a hearing aid comprising a receiver and signal processor circuitry operatively connected hereto. The signal processor circuitry comprises amplifying means (e.g., a Class D amplifier) adapted to generate a switched output voltage for driving the receiver of the hearing aid. Moreover, a power supply unit is included and is adapted to generate a DC output voltage from the switched output voltage. The present invention further relates to an associated method for generating a DC output voltage.

Abstract: The invention is directed to echo cancellation for a microphone system. An exemplary microphone system comprises a first transistor, wherein a gate terminal of the first transistor is connected to a ground terminal via a microphone electret element, the microphone electret element being associated with a capacitance and a voltage, the microphone electret element reverse biasing the first transistor; and a second transistor in parallel with the first transistor, wherein a gate terminal of the second transistor is connected to the ground terminal via a capacitor, the capacitance of the capacitor being selected to suppress at least a portion of a common mode signal, and wherein the gate terminal of the second transistor is not connected to the microphone electret element. The common mode signal comprises the echo, which may be the output of a speaker system that is received as input to the microphone system.

Abstract: An amplifier including an input stage, an output stage, an adjustable bias current generator and a level detector. The input stage may receive and amplify or buffer an input signal. The input stage may be biased by a first bias current. The output stage may supply an output signal to an amplifier load. The output stage may be biased with a second bias current. The adjustable bias current generator may be operatively coupled to the input stage and the output stage to supply these with the first and second bias currents, respectively. The level detector may be operatively coupled to the input signal and the adjustable bias current generator to control the first and second bias currents depending upon the input signal. The adjustable bias current generator may adjust the respective levels of first and second bias currents in opposite directions. Disclosed is an electroacoustical transducer incorporating the amplifier.

Abstract: A multi-mode amplifier with configurable DC-coupled or AC-coupled output is described. In one design, the multi-mode amplifier includes an amplifier and at least one DC level shifting circuit. The amplifier receives and amplifies an input signal and provides an output signal that is suitable for DC coupling to a load in a DC-coupled mode and for AC coupling to the load in an AC-coupled mode. The at least one DC level shifting circuit performs DC level shifting for at least one (e.g., input and/or output) common-mode voltage of the amplifier and is controlled based on whether the amplifier is operating in the DC-coupled or AC-coupled mode. The amplifier operates between VDD and VNEG supplies in the DC-coupled mode and between VDD and VSS supplies in the AC-coupled mode. The amplifier may include at least one gain stage, an internal DC level shifting circuit, and an output stage.

Abstract: A system and method for modulating the sound pressure that is output from an audio transducer is disclosed. In one embodiment, the method includes receiving an audio signal and placing the audio signal across a voice coil of the transducer. In addition, a voltage is applied across a field coil of the transducer, the field coil being separate from the voice coil. And the voltage that is applied across the field coil is adjusted so as to modulate the sound pressure output from the audio transducer.

Abstract: A system for controlling an electronic device, including an accessory coupled to the device having a control interface for receiving at least one input and a tone generator, the accessory configured to, in response to an input, generate a corresponding control tone using the tone generator, and send the control tone and a calibration sequence to the device. The device is operable to receive the calibration sequence and control tone. The device includes a zero-crossing detector operable to determine at least one of the start or ending of each of the calibration sequence and the control tone and having a circuit operable to determine the periods of the calibration sequence and the control tone based on the zero-crossing detector output.

Abstract: An audio apparatus includes: a connector that supports a multipolar plug including a plurality of plug terminals, the connector having a plurality of connector terminals including an input terminal of an audio collection section and an output terminal that outputs a noise canceling signal; a signal amplification section that amplifies a combined signal generated by combining the noise canceling signal and a reproduction audio signal, the signal amplification section being provided on an audio signal line that connects the input terminal and the output terminal; a detection section that detects whether the multipolar plug is inserted or pulled out by detecting change of voltage of a voltage supply line connected to the audio signal line; and a suppression section that suppresses output from the signal amplification section when the multipolar plug is pulled out but does not suppress the output when the multipolar plug is inserted.

Abstract: Systems and methods for adjusting a bias voltage and gain of the microphone to account for variations in a thickness of a gap between a movable membrane and a stationary backplate in a MEMS microphone due to the manufacturing process. The microphone is exposed to acoustic pressures of a first magnitude and a sensitivity of the microphone is evaluated according to a predetermined sensitivity protocol. The bias voltage of the microphone is adjusted when the microphone does not meet the sensitivity protocol. The microphone is then exposed to acoustic waves of a second magnitude that is greater than the first magnitude and a stability of the microphone is evaluated according to a predetermined stability protocol. The bias voltage and the gain of the microphone are adjusted when the microphone does not meet the stability protocol.

Abstract: A method of communicating with an electronic device. The method includes providing an electronic device having an audible sound receiving and generating sub-system including a microphone, transmitting from a source at least one acoustic signal encoded with information, receiving said at least one acoustic signal by said microphone and determining a spatial position, distance or movement of the microphone relative to the source, responsive to the received at least one signal.

Abstract: A capacitive transducer circuit comprises a capacitive transducer having first and second electrodes. The first and second electrodes are biased by respective first and second bias voltages. An amplifier is connected to receive a first analog signal on an input terminal, the first analog signal being generated by the capacitive transducer, and to generate a second analog signal on an output terminal. A digital feedback circuit is connected between the output terminal of the amplifier and the input terminal of the amplifier. The digital feedback circuit is configured to provide one of said first or second bias voltages. The output of a voltage source which provides the other bias voltage for the capacitive transducer may be filtered by a low pass filter. The low pass filter may comprise a switched capacitor filter circuit.

Abstract: Extending a microphone interface. One microphone interface extension includes a controller, a parent microphone, and a child microphone. The controller outputs a controller clock signal. The parent microphone receives the controller clock signal and generates a first data signal. The child microphone generates a second data signal and outputs the second data signal to the first parent microphone. The parent microphone receives the second data signal from the child microphone and outputs a combined data signal to the controller based on the first data signal and the second data signal. The parent microphone outputs the combined data signal to the controller on a phase of a microphone clock signal derived from the controller clock signal.

Abstract: A microphone includes a microelectromechanical system (MEMS) circuit and an integrated circuit. The MEMS circuit is configured to convert a voice signal into an electrical signal, and the integrated circuit is coupled to the MEMS circuit and is configured to receive the electrical signal. The integrated circuit and the MEMS circuit receive a clock signal from an external host. The clock signal is effective to cause the MEMS circuit and integrated circuit to operate in full system operation mode during a first time period and in a voice activity mode of operation during a second time period. The voice activity mode has a first power consumption and the full system operation mode has a second power consumption. The first power consumption is less than the second power consumption. The integrated circuit is configured to generate an interrupt upon the detection of voice activity, and send the interrupt to the host.

Abstract: A condenser microphone includes a condenser microphone unit and a piezoelectric element. The piezoelectric element is disposed so as to generate piezoelectric signals in response to vibration causing the unit to generate vibratory noise signals. The piezoelectric signals are inputted through a low-pass filter and a level adjuster circuit to the unit to drive a diaphragm of the unit. The vibratory noise signals generated by the vibration in the unit are canceled with the piezoelectric signals generated by the piezoelectric element.

Abstract: Electronic devices and accessories such as headsets for electronic devices are provided. A microphone may be included in an accessory to capture sound for an associated electronic device. Buttons and other user interfaces may be included in the accessories. An accessory may have an audio plug that connects to a mating audio jack in an electronic device, thereby establishing a wired communications link between the accessory and the electronic device. The electronic device may include power supply circuitry for applying bias voltages to the accessory. The bias voltages may bias a microphone and may adjust settings in the accessory such as settings related to operating modes. User input information may be conveyed between the accessory and the electronic device using ultrasonic tone transmission. The electronic device may also gather input from the accessory using a voltage detector coupled to lines in the communications path.

Abstract: A microphone assembly for use with an aftermarket telematics unit mounted in a passenger compartment of a vehicle is disclosed herein. The aftermarket telematics unit has a chamber having an opening that generally faces towards a rear of the vehicle and the microphone assembly includes, but is not limited to, a directional wideband microphone disposed within the chamber. A preamplifier is internally mounted within the directional wideband microphone. The preamplifier has an electrical lead and is both electrically and structurally attached to the aftermarket telematics unit via the electrical lead. The electrical lead is the sole means of physical attachment between the directional wideband microphone and the preamplifier, on the one hand, and the aftermarket telematics unit on the other hand.

Abstract: An Electret Condenser Microphone (ECM) motor apparatus includes a diaphragm ring support structure, a charge plate, and at least one stitch. The diaphragm ring support structure defines an opening there through. The charge plate is disposed within the opening. The at least one stitch is coupled to the diaphragm ring support structure to the charge plate. The diaphragm is disposed adjacent to and in a generally parallel relationship to the charge plate. The stitch is configured to hold the charge plate and the diaphragm ring, and the stitch is configured to maintain a constant or nearly constant distance between the charge plate and the diaphragm in the absence of sound energy.

Abstract: A directional microphone apparatus and directivity control method that corrects a level difference and a phase difference generated in a low band in a plurality of non-directional microphone units, improve the directivity, and reduce the size are provided. Level difference calculation section (105) calculates the level difference between first signal x1(t) obtained by first non-directional microphone unit (101) and second signal x2(t) obtained by second non-directional microphone unit (102), and correction parameter calculation section (106) calculates coefficients of a linear IIR filter configuring correction process section (103) based on the level difference. Correction process section (103) simultaneously corrects the level difference and a phase difference in the low band between two non-directional microphone units by using the calculated coefficients.

Abstract: A condenser microphone includes multiple condenser microphone units. Each unit includes an impedance converter. The condenser microphone units are connected in series such that outputs of the impedance converter in one of the condenser microphone units drive another of the condenser microphone units. A polarization voltage is accumulated to a DC voltage supplied from a DC voltage supply through a voltage adjuster to be applied to one of a diaphragm and a fixed electrode, and a voltage applied to the one of the diaphragm and the fixed electrode is adjusted by the voltage adjuster.

Abstract: A system and method are described for reducing the current consumption of a microphone component without adversely affecting performance. The system includes a micromechanical microphone capacitor, an acoustically inactive compensation capacitor, an arrangement for applying a high-frequency sampling signal to the microphone capacitor and for applying the inverted sampling signal to the compensation capacitor, an integrating operational amplifier which integrates the sum of the current flow through the microphone capacitor and the current flow through the compensation capacitor as a charge amplifier, a demodulator, which is synchronized with the sampling signal, for the output signal of the integrating operational amplifier, and a low-pass filter which uses the output signal of the demodulator to obtain a microphone signal that corresponds to the changes in capacitance of the microphone capacitor. The sampling signal is composed of a periodic sequence of sampling pulses and pause times.

Abstract: In accordance with embodiments of the present disclosure, a digital microphone system may include a microphone transducer and a digital processing system. The microphone transducer may be configured to generate an analog input signal indicative of audio sounds incident upon the microphone transducer. The digital processing system may be configured to convert the analog input signal into a first digital signal having three or more quantization levels, and in the digital domain, process the first digital signal to convert the first digital signal into a second digital signal having two quantization levels.

Abstract: In accordance with embodiments of the present disclosure, a digital microphone system may include a microphone transducer and a digital processing system. The microphone transducer may be configured to generate an analog input signal indicative of audio sounds incident upon the microphone transducer. The digital processing system may be configured to convert the analog input signal into a first digital signal having a plurality (e.g., more than 3) of quantization levels, and in the digital domain, process the first digital signal to compress the first digital signal into a second digital signal having fewer quantization levels (e.g., +1, 0, ?1) than that of the first digital signal.

Abstract: A low-noise pre-amplifier with an active load element is integrated into a microphone. The microphone has an acoustic sensor coupled to the intrinsic pre-amplifier. A controllable current source is coupled to the intrinsic pre-amplifier and supplies a pre-amplifier bias current. A current source controller is coupled to the current source and controls the amplitude of the pre-amplifier bias current to maintain the intrinsic pre-amplifier at a bias point at which the intrinsic pre-amplifier amplifies microphone signals produced by the acoustic sensor. The intrinsic pre-amplifier may be actively regulated at the pre-determined bias point using negative feedback. Alternatively, the intrinsic pre-amplifier may be set to the pre-determined bias point by sweeping the pre-amplifier bias current for the intrinsic pre-amplifier over a range of currents.

Abstract: In accordance with an embodiment, a circuit includes an oscillator having an oscillation frequency dependent on an input signal, a digital accumulator having a first input coupled to an output of the oscillator, a digital-to-analog converter (DAC) coupled to an output of the digital accumulator, an analog loop filter coupled to an output of the digital-to-analog converter, and a comparison circuit having an input coupled to an output of the analog loop filter and an output coupled to a second input of the digital accumulator.

Abstract: This document discusses apparatus and methods for configuring and providing crosstalk cancellation to maintain channel separation in a multi channel system. In an example, an amplifier circuit can include a crosstalk cancellation circuit configured to reduce crosstalk from a first output to a second load and from a second output to a first load where the first load and the second load share a return path.

Abstract: The present invention discloses a driving circuit for electronic horn and a driving method for the electronic horn. The driving circuit includes an oscillating circuit, which generates a signal having oscillating frequency. Based on the signal, said driving circuit generates a driving signal to drive the electronic horn to produce sound. It is characterized in that said oscillating circuit includes a variable capacitor, and the oscillating frequency is changed by adjusting capacitance of the variable capacitor so as for the frequency of the driving signal to be consistent with working frequency of the electronic horn. The present invention overcomes the problem of mismatch between the frequency of circuit's driving signal and the horn's sounding diaphragm and horn's tone inflexion due to resistance change caused by vehicle vibration.

Abstract: An electronic device may contain an input-output device such as a speaker, vibrator, or near field communications antenna. The input-output device may include an inductor. The inductor in the input-output device may be shared by wireless charging circuitry in the electronic device so that wireless charging signals can be converted into power to charge a battery in the electronic device. A separate inductor may also be provided within an input-output device to support wireless charging. A drive circuit may supply drive signals to the input-output device such as audio signals, vibrator control signals, or near field communications output signals for external near field communications equipment. An input amplifier that is coupled across the inductor in the input-output device may be used in receiving near field communications signals.

Abstract: There is provided a capacitor microphone comprising a microphone capsule (100), which has an at least partially electrically conductive diaphragm (110) and a counterelectrode (120) associated therewith. The counterelectrode (120) has a printed circuit board (21) having a carrier of an insulating material (121a) and at least one electrically conductive surface (121b).

Abstract: Systems, methods, and apparatus to filter audio are disclosed. An example device includes first and second audio speakers having first audio characteristics, a third audio speaker having second audio characteristics, wherein the third speaker is positioned between the first and second audio speakers, a first audio filter to process an audio input signal to have a first frequency response including a first cutoff frequency, the first audio filter to output a first audio output signal to the first audio speaker, and a second audio filter to process the audio input signal to have a second frequency response to compensate for interference between the first and second frequency responses caused by a position of the first audio speaker relative to the second audio speaker.

Abstract: In one aspect, a microphone with closely spaced elements is used to acquire multiple signals from which a signal from a desired source is separated. The signal separation approach uses a combination of direction-of-arrival information or other information determined from variation such as phase, delay, and amplitude among the acquired signals, as well as structural information for the signal from the source of interest and/or for the interfering signals. Through this combination of information, the elements may be spaced more closely than may be effective for conventional beamforming approaches. In some examples, all the microphone elements are integrated into a single a micro-electrical-mechanical system (MEMS).

Abstract: A transducer assembly utilizing at least two MEMS transducers is provided, the transducer assembly preferably defining either an omnidirectional or directional microphone. In addition to at least first and second MEMS transducers, the assembly includes a signal processing circuit electrically connected to the MEMS transducers, a plurality of terminal pads electrically connected to the signal processing circuit, and a transducer enclosure housing the first and second MEMS transducers. The MEMS transducers may be electrically connected to the signal processing circuit using either wire bonds or a flip-chip design. The signal processing circuit may be comprised of either a discrete circuit or an integrated circuit. The first and second MEMS transducers may be electrically connected in series or in parallel to the signal processing circuit. The first and second MEMS transducers may be acoustically coupled in series or in parallel.

Abstract: A microphone includes a microphone unit having a diaphragm, a fixed electrode and a FET as an impedance converter; a plug outputting audio signals output from the microphone unit; and a jack into which audio signals inputted in the microphone unit are inputted. While the plug of the other microphone is inserted in the jack of the microphone, the audio signals output from the other microphone unit are added to the audio signals output from the microphone unit and are output.

Abstract: A microphone system has a package with a top, a bottom, and four sides that at least in part form an interior chamber. One of the sides forms an inlet aperture for communicating the inlet chamber with the exterior environment. The system also has first and second microphone dies, in a stacked relationship, respectively having a first and second diaphragms. A circuit die, positioned in electrical communication with the first and second microphone dies, is configured to mitigate vibrational noise from the first microphone die using a signal produced by the second microphone die or vice versa. The first and second microphone dies are positioned so that the first and second diaphragms are substantially the same distance from the inlet aperture in the side.

Abstract: Systems and methods for suppressing pop-up noise in an audio signal are disclosed. The system includes a driver circuit shared by a pin interface and a complementary pin interface. A control unit is coupled to the pin interface and the complementary pin interface. To activate the pin interface, the control unit is configured to first activate the driver output at the complementary pin interface. Once the complementary pin interface achieves a preset voltage, the driver output is switched to the pin interface by the control unit. In addition, the driver circuit can be calibrated for a DC offset on the complementary pin interface by re-using calibration data calculated at the pin interface. Further, DC correction signals can be provided from a pre-biasing circuit based on the calibration data of the driver circuit.

Abstract: A membrane pressure-sensitive switch includes a circuit board provided with an electrode pattern detecting electrical conductivity, a membrane having a conductive surface, and a spacer interposed between the membrane and the circuit board. The electrode pattern is surrounded by a ground pattern on the front surface of the circuit board. The ground pattern on the front surface is connected to another ground pattern on the rear surface of the circuit board. The spacer is composed of a conductive material. The conductive surface of the membrane, the ground pattern on the front surface of the circuit board, and the spacer are electrically conducted. The electrode pattern is disposed between the conductive surface of the membrane and the other ground pattern on the rear surface of the circuit board.

Abstract: A MEMS microphone is capable of operating with less-than-one-volt bias voltage. An exemplary MEMS microphone can operate directly from a power rail (i.e., directly from VDD), i.e., without a DC-to-DC step-up voltage converter or other high bias voltage generator. The MEMS microphone has high mechanical and electrical sensitivity due, at least in part, to having high-compliance, i.e. low stiffness, springs and a relatively small gap between its diaphragm and its parallel conductive plate. In some embodiments, a diode-based voltage reference or a bandgap voltage reference supplies the bias voltage.

Abstract: A method of distinguishing sound sources includes the step of transforming data, collected by at least two transducers which each react to a characteristic of an acoustic wave, into signals for each transducer location. The transducers are separated by a distance of less than about 70 mm or greater than about 90 mm. The signals are separated into a plurality of frequency bands for each transducer location. For each band a comparison is made of the relationship of the magnitudes of the signals for the transducer locations with a threshold value. A relative gain change is caused between those frequency bands whose magnitude relationship falls on one side of the threshold value and those frequency bands whose magnitude relationship falls on the other side of the threshold value. As such, sound sources are discriminated from each other based, on their distance from the transducers.

Abstract: A microphone can include a capacitor capsule, an output buffer amplifier connected to the output of the capacitor capsule, and an audio limiter connected to the output of the output buffer amplifier, wherein the audio limiter limits the output level of the microphone at a threshold level. The microphone can include an adjustable output level. The microphone can include an integrated high-pass filter. The microphone can have an omnidirectional polar pattern.

Abstract: A method of optimizing a parametric emitter system having a pot core transformer coupled between an amplifier and an emitter, the method comprising: selecting a number of turns required in a primary winding of the pot core transformer to achieve an optimal level of load impedance experienced by the amplifier; and selecting a number of turns required in a secondary winding of the pot core transformer to achieve electrical resonance between the secondary winding and the emitter.

Abstract: A digital microphone, the microphone includes a microelectromechanical (MEMS) component and a frequency boost component. The MEMS component is configured to convert. sound into an electrical signal. The frequency boost component is configured to receive the electrical signal and ultrasonically boost the electrical signal to create a frequency response. The frequency response does not substantially affect an audio band of interest of the microphone.

Abstract: Electric power is provided to a two-way communications headset by creating a differential DC voltage potential between a ground conductor associated with a microphone of that headset and a ground conductor associated with an acoustic driver of that headset, thereby enabling that headset to refrain from drawing electric power from a more limited local power source.

Abstract: A system is provided to protect a loudspeaker (144) by controlling a level of an applied audio signal. A control signal is generated by applying an input audio signal (115) to the collective operations of a gain control system (100). The gain control system (100) uses the input audio signal (115) in conjunction with at least one parameter to derive an estimated stress associated with the loudspeaker (144). The estimated stress is compared with a protection threshold stress (127). If the protection threshold stress is exceeded, a gain applied by a gain component (134) is selectively adjusted to modify the input audio signal (115). The resulting gain-controlled audio signal (116) is employed to drive the loudspeaker (144).

Abstract: Electric power is provided to a two-way communications headset by creating a differential DC voltage potential between a ground conductor associated with a microphone of that headset and a ground conductor associated with an acoustic driver of that headset, thereby enabling that headset to refrain from drawing electric power from a more limited local power source.

Abstract: Charge pump circuits having circuit components such as transistors which may be damaged by voltage transients greater than the normal operating voltage levels of the charge pump circuit, such as may be experienced during powering down. The circuit components to be protected are connected in parallel with a leakage element arranged to have a leakage current that is small enough during normal operation to allow the charge pump to operate effectively but which is large enough, during development of a voltage transient, to prevent excess voltage levels being achieved. The leakage element may have a significant leakage current at a voltage less than the breakdown voltage of the circuit component. Suitable leakage elements are poly diodes.

Abstract: To suppress the transverse displacement of a ribbon due to an impact to a level smaller than that achieved by electromagnetic damping. The switch 150 breaks a path between the piezoelectric element 140 and the secondary winding 132 so as to be non-conductive when a power plug is connected (the microphone is in use), and completes a path between the piezoelectric element 140 and the secondary winding 132 so as to be conductive when a power plug is not connected (the microphone is not in use), in order to generate a driving force in the direction opposite to the displacement direction of the ribbon 10 by causing a current corresponding to power generated in the piezoelectric element 140 to flow in the ribbon 10.

Abstract: The present invention relates to an integrated circuit voltage pump with temperature compensation circuitry providing improved DC output voltage accuracy over an operational temperature range. The compensation circuitry is operative to eliminate or reduce temperature induced changes of voltage drops across semiconductor diodes of the integrated circuit voltage pump.

Abstract: An apparatus for use with an electronic device having a microphone. The apparatus comprises a structure configured to detachably couple to the device, and a generator supported by the structure. The generator is configured to generate a force that acts on the microphone and renders the microphone unresponsive to voice sounds.

Abstract: An ultrasonic audio speaker includes an emitter and a driver. The emitter can include a first layer having a conductive surface; a second layer having a conductive surface; and an insulating layer disposed between the first and second conductive surfaces, wherein the first and second layers are disposed in touching relation to the insulating layer. The driver circuit can include two inputs configured to be coupled to receive an audio modulated ultrasonic signal from an amplifier and two outputs, wherein a first output is coupled to the conductive surface of the first layer and the second output is coupled to the conductive surface of the second layer.

Abstract: In order to mount a plurality of kinds of earphone microphones, a mobile phone includes an earphone microphone terminal to accept either a plug of a PTT earphone microphone or a plug of an earphone microphone, and an earphone microphone switching portion to detect whether the PTT earphone microphone or the earphone microphone is accepted and switch a contact point between a plurality of contact points of the earphone microphone terminal depending on the kind of the detected earphone microphone.

Abstract: The invention relates an electrostatic speaker system comprising—a high voltage switching power amplifier,—an extraction filter having an input coupled to an output of the high voltage switching amplifier, and—an electrostatic speaker element having a capacitive load and an input coupled to an output of the extraction filter. The combination of the extraction filter and capacitive load form a filter circuitry having at least a first filter stage and a second filter stage. The first filter stage comprising a RLC circuit having a resonant frequency ?O and a quality factor Q>½ and wherein the second filter stage being a low pass filter comprises at least one electrical element for damping a signal component at the resonant frequency of the RLC circuit at the output of the extraction filter.

Abstract: Displacement of a moving diaphragm in an electroacoustic transducer is measured by modulating an electrical signal based on changes in capacitance between the voice coil assembly and the magnetic structure resulting from relative motion between the voice coil and the magnetic structure. The modulated electrical signal is demodulated to produce an output signal having a value proportional to the displacement.