Abstract: This document discusses, among other things, circuits and methods for providing an indication of an impedance between a detecting pin and a first signal pin of an audio socket using first and second comparators to, among other things, determine if moisture is present in the audio socket. If moisture is present in the audio socket, communication between an audio processing unit and the audio socket can be disabled.

Abstract: Audio transmitter circuitry is disclosed that is configurable into different modes by the user, and can output either a differential or single-ended audio signal on two signal wires. Depending on the mode, the transmitter deals with noise on the signal wires by adjusting the input resistance that such noise sees looking into the transmitter. If the transmitter is configured in a differential mode, the input resistance looking back into the transmitter from the perspective of the noise on both signal wires is relatively high. If the transmitter is configured in a single ended mode, the input resistance of noise looking back from the active signal wire into the transmitter is relatively low, to in effect ground such noise back into the transmitter, without significantly presenting such noise to the receiver.

Abstract: An automated noise reduction circuit is configured to find an audio output with the lowest voltage level associated with undesirable noise. The circuit may include a plurality of audio input ports, ground isolation devices, electronic switches and a microprocessor. The microprocessor may be configured to toggle the ground isolation devices on and off, sample voltage at an output of the ground loop isolation transformers when the ground isolation devices are on and off, and switch the ground isolation devices to a position that produces a lowest voltage output based on a comparison of sampled voltage that is analyzed by a set of algorithms programmed into the microprocessor and that has been sampled from the output of the ground isolation devices for each of the multiple input ports.

Abstract: Provided are methods and systems for noise suppression within multiple time-frequency points of spectral representations. A multi-feature cluster tracker is used to track signal and noise sources and to predict signal versus noise dominance at each time-frequency point. Multiple features, such as binaural and monaural features, may be used for these purposes. A Gaussian mixture model (GMM) is developed and, in some embodiments, dynamically updated for distinguishing signal from noise and performing mask-based noise reduction. Each frequency band may use a different GMM or share a GMM with other frequency bands. A GMM may be combined from two models, with one trained to model time-frequency points in which the target dominates and another trained to model time-frequency points in which the noise dominates. Dynamic updates of a GMM may be performed using an expectation-maximization algorithm in an unsupervised fashion.

Abstract: A driver circuit includes a first driver amplifier that is configured to generate a first output in response to a first reference voltage input and a first audio input; a second driver amplifier that is configured to generate a second output in response to the first reference voltage and a second audio input; and a common mode (CM) amplifier, coupled to the first driver amplifier and the second driver amplifier. The CM amplifier is configured to generate an output in response to a second reference voltage input, the first reference voltage input being a divided version of the output. Gains of the first driver amplifier, second driver amplifier and the CM amplifier are equal. Noise at the output appears across a plurality of resistors coupled at the outputs of the first driver amplifier, second driver amplifier and the CM amplifier and cancels with respect to the output of the CM amplifier.

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 signal processing apparatus includes: one or more detection means for detecting movement of a diaphragm of a speaker in correspondence with feedback methods that are different feedback methods; analog-to-digital conversion means for converting one or more detection signals acquired by the detection means into a digital form; feedback signal generating means for generating feedback signals corresponding to the feedback methods using the digital detection signals; synthesis means for combining an audio signal to be output as a driving signal of the speaker with the feedback signals; correction equalizer means for setting an equalizing characteristic to allow a sound reproduced by the speaker to have a target frequency characteristic by changing the digital audio signal; feedback operation setting means for setting feedback methods in which a feedback operation up to combining the audio signal with the feedback signal is performed and the feedback operation is not performed equalizing characteristic changing a

Abstract: The present disclosure provides an earphone power amplifier, including a ground contact connected to a ground wire of an earphone, a left sound channel power amplifying circuit connected to a left sound channel of the earphone, and a right sound channel power amplifying circuit connected to a right sound channel of the earphone. The left sound channel power amplifying circuit includes a first operational amplifier and a first positive feedback exported from an input end of the first ferrite bead to an in-phase input end of the first operational amplifier, the right sound channel power amplifying circuit includes a second operational amplifier and a second positive feedback exported from the input end of the first ferrite bead to an in-phase input end of the second operational amplifier.

Abstract: According to some aspects, an electronic device adapted to provide audio output via an audio system. The electronic device includes an audio jack adapted to be coupled to the audio system. The audio jack includes a line-out for sending audio signals to the audio system and a ground return line. The electronic device also includes a ground resistor between the ground return line and a ground node. The ground resistor has a resistance selected to reduce ground current on the ground return line when the electronic device is being charged without significantly adversely affecting the quality of the audio output.

Abstract: Techniques herein provide wireless energy transfer to audio devices such as headphones, headsets, hearing aids, and the like. Audio devices are integrated with a device resonator. The device resonator may be positioned and oriented to reduce interaction with lossy or sensitive components of the audio device. A repeater resonator and/or a source resonator is integrated into a headrest of a seat or a chair providing continuous power to the headphones while in use. The audio devices may be recharged wirelessly when positioned near source resonators that may be embedded in pads, tables, carrying cases, cups, and the like.

Abstract: An output circuit for audio codec chip includes a noise eliminating circuit electrically coupled to the audio codec chip for eliminating noise signals. The noise eliminating circuit includes a first switch and a second switch. When the audio codec chip output signals jump from low voltage level to high voltage level, the noise signals are grounded via the first and second switches respectively.

Abstract: The present invention discloses a circuit with three-stage of power-on sequence used for suppressing the pop noise in audio system. It mainly comprises a first resistor (R1); a capacitor (Cout); a first switch (SW1); a second switch (SW2); a soft start device; a first feedback amplifier; and a second feedback amplifier. By using the three-stage of power-on sequence, the present invention can effectively suppress the pop noise when the audio driver is power on.

Abstract: The invention provides a noise removal device and method capable of more proper interpolation on an input signal. The noise removal device is for removing noise in an input signal and includes: a noise detector detecting noise in an IF signal and outputting a noise detection signal; an interpolation controller determining a period and amount of interpolation for noise correction processing, based on the IF signal and the noise detection signal; and a noise gate processor performing the noise correction processing on the IF signal, based on the interpolation period and amount supplied from the interpolation controller. The interpolation controller sets a predetermined first interpolation period, based on a first noise detection signal inputted from the noise detector, and redefines a second interpolation period longer than the first interpolation period when a second noise detection signal is detected within the first interpolation period.

Abstract: An active noise reduction system is provided for receiving an audio input signal and a noise interference signal and calculating an audio broadcasting signal according to a Feedback Filtered-X Least-Mean-Square (FFXLMS) algorithm, wherein the FFXLMS algorithm optimizes a (convergence factor) ? so as to decrease the numbers of divisions operated by the active noise reduction system and increase the operation speed of the active noise reduction system.

Abstract: According to some aspects, an electronic device adapted to provide audio output via an audio system. The electronic device includes an audio jack adapted to be coupled to the audio system. The audio jack includes a line-out for sending audio signals to the audio system and a ground return line. The electronic device also includes a ground resistor between the ground return line and a ground node. The ground resistor has a resistance selected to reduce ground current on the ground return line when the electronic device is being charged without significantly adversely affecting the quality of the audio output.

Abstract: The invention provides a microphone circuit. In one embodiment, the microphone circuit comprises a transducer, a biasing resistor, a pre-amplifier, and a switch circuit. The transducer is coupled between a ground and a first node for converting a sound into a voltage signal output to the first node. The biasing resistor is coupled between the ground and the first node. The pre-amplifier is biased with a biasing voltage and coupled between the first node and a second node, and amplifies the voltage signal to obtain an output signal at the second node. The switch circuit is coupled between the first node and the ground, couples the first node to the ground when the microphone circuit is reset, and decouples the first node from the ground after a voltage status of the microphone circuit is stable, thus clamping a voltage of the first node to the ground to prevent generation of a popping noise when the microphone circuit is reset.

Abstract: A vehicle entertainment system and method that alternately configures an input of the entertainment system as a differential input that is decoupled from a ground point, or as ground referenced input that is coupled to a ground point. A noise detector determines a noise signal value for a ground switch module that alternately changes a switch state between a coupled state that couples the common connection to the ground point, and a decoupled state that decouples the common connection from the ground point, based upon the noise signal value being greater than a threshold.

Abstract: An amplifier power-down apparatus for suppressing transient signals in a circuit, for example an audio circuit, comprising a reference voltage generator circuit for generating a reference voltage. The reference voltage generator circuit comprises a capacitor for maintaining the reference voltage at a desired level. The amplifier power-down apparatus comprises a discharge control circuit for controlling the operation of the reference voltage generator circuit during power-down. The discharge control circuit comprises an amplifier with a positive feedback path for controlling a current flow from the capacitor during power-down.

Abstract: An amplifier start-up apparatus for reducing transient signals in a circuit, for example an audio circuit, comprising a reference voltage generator circuit for generating a reference voltage. The reference voltage generator circuit comprises a capacitor for maintaining the reference voltage at a desired level. The amplifier start-up apparatus comprises a control circuit for controlling the operation of the reference voltage generator circuit during power-up. The control circuit comprises an amplifier with a positive feedback path for controlling a current flow to the capacitor.

Abstract: A speaker array and microphone arrays positioned on both sides of the speaker array are provided. A plurality of focal points each serving as a position of a talker are set in front of the microphone arrays respectively symmetrically with respect to a centerline of the speaker array, and a bundle of sound collecting beams is output toward the focal points. Difference values between sound collecting beams directed toward the focal points that are symmetrical with respect to the centerline are calculated to cancel sound components that detour from the speaker array to microphones. Then, it is estimated based on totals of squares of peak values of the difference values for a particular time period that the position of the talker is close to which one of the focal points, and the position of the talker is decided by comparing the totals of the squares of the peak values of the sound collecting beams directed to the focal points that are symmetrical mutually.

Abstract: A method for reducing audio noise of a display is provided. A horizontal synchronization signal, a reference signal and a substrate voltage signal are generated. The reference signal has a preset width at high level status. The status transition of the substrate voltage signal is based on each scan line corresponding to the horizontal synchronization signal. In each period of the substrate voltage signal, the status transition of the raising and falling edges is based on the high level status of the reference signal, and the transition timings of the raising edges and the falling edges are advanced or delayed based on a reference value of the high level status of the reference signal.

Abstract: Hybrid circuits for electronic devices and accessories for electronic devices are provided. One or more pairs of hybrid circuits may convey audio signals, noise cancellation audio signals, microphone signals, control signals, and other signals between an electronic device and an accessory. The hybrid circuits may include a voltage controlled current source, a differential amplifier, separate signal and ground pins, multiple ground lines, an amplifier on a ground noise sense input line that can sense ground noise that may result from parasitic resistance, and other circuitry.

Abstract: A method for reducing audio noise of a display is provided. A horizontal synchronization signal, a reference signal and a substrate voltage signal are generated. The reference signal has a preset width at high level status. The status transition of the substrate voltage signal is based on each scan line corresponding to the horizontal synchronization signal. In each period of the substrate voltage signal, the status transition of the raising and falling edges is based on the high level status of the reference signal, and the transition timings of the raising edges and the falling edges are advanced or delayed based on a reference value of the high level status of the reference signal.

Abstract: A noise reduction circuit for reducing the effects of low frequency noise such as wind noise in communications applications is described. In one embodiment, the noise reduction circuit features a high pass filter formed by exploiting the existing off-chip AC coupling capacitances in making the connection to the source of audio signals. The filter may be adaptive to environmental low frequency noise level through programming the shunt resistances. A low-noise wide dynamic range programmable gain amplifier is also described. Adaptive equalization of the audio signal is also described through the utilization of programmable front-end resistors and a back-end audio equalizer.

Abstract: An impedance selection circuit for the connection of multiple circuit braches is disclosed. The connection is supplied with the use of three switching jacks and connects directly to the branches through two jacks, or combines the branches in parallel or series to output to one jack. This circuit design comprises a low impedance jack 1, a middle impedance jack 2, and a high impedance jack 3. These jacks will connect to the multiple circuit branches individually, in series, or in parallel. In an example of using the impedance selection circuit, the user can implement the circuit to connect an amplifier to a multi-speaker array at three different impedances. The low impedance jack 1 yields a connection at a smallest fraction of the individual speakers' impedance. The middle impedance jack 2 yields a connection at a larger fraction such as one half the individual speakers' impedance. The high impedance jack 3 yields a connection at a higher impedance such as the same impedance as each individual speaker.

Abstract: An induction-type loopset is provided that is connectable to a wireless device. The loopset contains a first coil electromagnetically coupled to a t-coil hearing aid and an impedance-matching device coupled to the first coil. The impedance-matching device is responsive to an audio signal from the wireless device. The induction-type loopset is powered from the power source of the wireless device. The power source is responsive to an activation state of the wireless device.

Abstract: A current flow inhibiting device or hum eliminator, such as one or more specially configured diodes or other electronic component, is placed in series with the normal ground line before it is connected to the end device. This prevents the flow of current through the ground wire. Accordingly voltages of any frequency are stopped from converting to a current flow, thereby reducing or eliminating noise in the electrical circuit and in audible signals.

Abstract: A shock sound prevention circuit which provides a BTL audio amplifier with stable operation about 100 msec after turning-on of a power supply is required. Since the BTL audio amplifier is usually integrated in an IC, use of capacitors which takes up a large pattern area on the IC chip needs to be minimized. This invention offers a shock sound prevention circuit which has a capacitance for reference voltage to generate a reference voltage which rises according to turning-on of a power supply, a first operational amplifier to which an audio signal input and the reference voltage are applied, a second operational amplifier to which a reverse signal of the audio signal input and the reference voltage are applied, a first and a second buffers to which the reference voltage is applied and a level comparator which compares a voltage of the power supply with the reference voltage.

Abstract: The present invention discloses a method of reducing a noise generated from a speaker at the time of power on/off with a simple configuration in an audio output device that drives a speaker. For its achievement, the audio output device using the noise reduction method according to the present invention is provided with a digital DC attenuator, a D/A converter, and an operational amplifier. The digital DC attenuator functions to gradually change an output digital value from a first digital value to a second digital value. The D/A converter functions to convert an output from the digital DC attenuator into an analog signal. The operational amplifier functions to amplify an output from the D/A converter and thus drives a speaker. At the time of power on, the output from the digital DC attenuator is gradually changed from a digital value corresponding to the ground level to a digital value corresponding to the signal ground value.

Abstract: A second-order adaptive differential microphone array (ADMA) has two first-order elements (e.g., 802 and 804 of FIG. 8), each configured to convert a received audio signal into an electrical signal. The ADMA also has (i) two delay nodes (e.g., 806 and 808) configured to delay the electrical signals from the first-order elements and (ii) two subtraction nodes (e.g., 810 and 812) configured to generate forward-facing and backward-facing cardioid signals based on differences between the electrical signals and the delayed electrical signals. The ADMA also has (i) an amplifier (e.g., 814) configured to amplify the backward-facing cardioid signal by a gain parameter; (ii) a third subtraction node (e.g., 816) configured to generate a difference signal based on a difference between the forward-facing cardioid signal and the amplified backward-facing cardioid signal; and (iii) a lowpass filter (e.g.

Abstract: Method for transmitting charging signals via a data transmission path using resonance phenomena The invention provides a method for transmitting charging signals, in which an electrical resonance effect is provided, with an output current (100) being emitted from a line current driver device (202), which output current (100) is passed through a data path filter block (201), which has a data transmission path unit (122) and a matching filter unit (123), to a line impedance (102), and the matching filter unit (123) and the data transmission path unit (122) are set such that an electrical resonance effect occurs, which leads to a voltage peak occurring in a line voltage level (101).

Abstract: A filter for suppressing noise surges and noise frequencies in ac power lines to an audio video load includes at least one noise suppression circuit. The noise suppression circuit in turn includes first and second inductors coupled to respective power lines in series with the load. A capacitor is coupled between the power lines at the input of the first inductor and the output of the second inductor. With this arrangement, the capacitor suppresses noise surges in the power line, while being protected by the second inductor from being damaged by the surges. Also, the filter suppresses two noise frequencies using only the single capacitor. If desired, additional noise suppression circuits can be provided, with each noise suppression circuit suppressing two noise frequencies using only a single capacitor.