Abstract: A driving circuit for a sound outputting apparatus includes a H-bridge and a charge pump established by six switches for driving two types of loudspeakers, respectively. The six switches include two common switches to be configured in the H-bridge and the charge pump, thereby reducing the costs and circuit area of the driving circuit.

Abstract: This high fidelity audio amplifier with very low distortion and high efficiency (10) includes: an input (12) for an audio signal to be amplified and an output (14) for feeding a load (16) with the amplified audio signal; a reference voltage generator (18) having very high linearity and low output impedance, capable of receiving as an input the musical signal to be amplified; a power voltage generator (20), the output of which is connected to the output of the reference voltage generator (18), through a coupling impedance (22), the modulus of which is at least ten times lower than the modulus of the impedance of the load (16) capable of being fed by the output (14) of the amplifier; and means (28A, 28B, 30, 32) for inputting at the input of the power voltage generator (20), a representative signal of the current provided at the output by the reference voltage generator (18).

Abstract: An audio amplification apparatus for attachment to a device having a loudspeaker. The apparatus (10) comprises a vibration transducer (30) for attachment to the device having the loudspeaker (20), an amplifier (40) coupled to the vibration transducer (30) for amplifying an electrical signal representing at least in part an audible output of the loudspeaker (24), and an audio output port (52) operably coupled to the amplifier, thereby permitting connection to an audio output device (60).

Abstract: According to one embodiment, an electronic apparatus includes a terminal, an amplifier, a speaker, a power supply circuit and a first controller. The terminal configured to input an audio signal from an external device. The amplifier configured to amplify the audio signal. The speaker configured to output sound corresponding to the audio signal which is amplified by the amplifier. The power supply circuit configured to supply power to the amplifier. The first controller configured to control the power supply circuit to continue the supply of the power, when the electronic apparatus is in a non-operative state.

Abstract: An inverting amplifier which drives headphones via an output capacitor includes: an operational amplifier, an input resistor having a first terminal via which an audio signal to be amplified is received, and a second terminal connected to an inverting input terminal of the operational amplifier; and a feedback resistor having a first terminal connected to an inverting input terminal of the operational amplifier, and a second terminal connected to the output terminal. A reference voltage source generates a bias voltage Vb, and supplies it to the non-inverting input terminal. A discharging path includes a discharging resistor and a first switch arranged in series between an output terminal of the reference voltage source and an fixed voltage terminal. A second switch is arranged between the output terminal of the operational amplifier and a node on the discharging path where the electric potential is higher than it is at the discharging resistor.

Abstract: An electronic volume circuit includes a first signal processing circuit and a second signal processing circuit that are cascaded together. The first signal processing circuit includes a first operational amplifier including an input terminal and an output terminal, one or more input resistors inputting one or more signals to the input terminal of the first operational amplifier, and a feedback resistor connected between the input terminal and the output terminal of the first operational amplifier. The second signal processing circuit includes a second operational amplifier including an input terminal and an output terminal, an input capacitor inputting a signal output from the first operational amplifier to the input terminal of the second operational amplifier, and a resistor and a capacitor connected in parallel between the input terminal and the output terminal of the second operational amplifier.

Abstract: The present invention provides a digital condenser microphone having a preamplifier with variable input impedance and a method of controlling the variable input impedance of the preamplifier. The preamplifier includes a bias terminal (Bias) for applying a bias voltage to an input signal when the input signal is output from a microphone condenser. An impedance unit (Z) includes at least one variable input impedance element which is connected to the bias terminal and to which the bias voltage is applied via the bias terminal. An operational amplifier receives the input signal, converts the input signal into an output signal, and outputs the output signal. A control block (40) determines whether a DC voltage level of the output signal output from the operational amplifier has reached a reference value, and controls a total impedance of the impedance unit based on a result of the determination.

Abstract: Described herein is a preamplifier circuit for a capacitive acoustic transducer provided with a MEMS detection structure that generates a capacitive variation as a function of an acoustic signal to be detected, starting from a capacitance at rest; the preamplifier circuit is provided with an amplification stage that generates a differential output signal correlated to the capacitive variation. In particular, the amplification stage is an input stage of the preamplifier circuit and has a fully differential amplifier having a first differential input (INP) directly connected to the MEMS detection structure and a second differential input (INN) connected to a reference capacitive element, which has a value of capacitance equal to the capacitance at rest of the MEMS detection structure and fixed with respect to the acoustic signal to be detected; the fully differential amplifier amplifies the capacitive variation and generates the differential output signal.

Abstract: An audio system including wireless speakers. The wireless speakers include rechargeable batteries and are interchangeable so that two loudspeakers may be recharged while two loudspeakers are operating wirelessly.

Abstract: An amplifier for amplifying a differential audio signal, having common-mode rejection and digital gain control, includes a current source (401) which supplies a constant level of current to a first current path (I1) and a second current path (I2), and input stage (403) which modulates the current in the current paths in response to a differential input signal, and an output stage (405) which produces an output signal by amplifying the difference in current between the current paths, a degree of feedback provided to the input stage by a feedback stage (402) that modulates the current in the current paths in response to the output signal, and the degree of modulation by the feedback stage is determined by the attenuation provided by at least one multiplying digital-to-analog converter (407) located therein.

Abstract: The invention relates to an amplifier circuit (10a, 10b) for a two-wire interface, comprising a first current path (1), comprising a voltage-controlled current source (T1) having a gate (GT1), which is connected to an input connection (E1) of the amplifier circuit. A second current path (2) of the amplifier circuit comprises a voltage-controlled current source (T2), which is connected in series with the second resistor (R2). The first resistor (R1) and a parallel connection of the first and second current paths (1, 2) are connected in series between an output connection (A) and a reference voltage connection (B) of the amplifier circuit. The amplifier circuit (10a, 10b) makes it possible to adjust the gain and to provide a supply voltage and a useful signal over a common conducting track (L).

Abstract: An amplifier circuit which, includes a first input for receiving a first input signal and a second input for receiving a second input signal. A first amplifier section is connected to the first input and the second input is present. The first amplifier section can combine the first signal and the second signal into a first combined signal, the first amplifier being connected to a first output, for outputting the first combined signal. A second amplifier section is connected to the first input and the second input, for combining the first signal and the second signal into a second combined signal, the second amplifier being connected to a second output, for outputting the second combined signal. A common mode section is connected to the first input and the second input, for generating a common mode signal based on a combination of the first signal and the second signal and outputting the common mode signal at a common output connected to the common mode amplifier.

Abstract: A method of outputting an audio signal includes receiving an audio signal; generating a carrier waves having phases differing from each other; generating modulation signals by comparing the respective carrier waves with the audio signal; amplifying the modulation signals; and outputting the amplified modulation signals.

Abstract: A headset used as an external louder speaker and a method for adjusting an output of the speaker transducers are disclosed. The headset includes a signal receiver, speaker parts, hinge parts, and amplifiers. The speaker parts change their direction through the hinge parts. The output of speaker transducers is adjusted according to the direction of the speaker parts. When the output of speaker transducers is increased, the speaker parts of the headset are used as an external speaker.

Abstract: An apparatus of the present disclosure enhances the audio/visual experience of a portable digital device, and comprises a lens positioning slot, a lens storage compartment, a passive audio amplifier, a receiving station.

Abstract: Methods and apparatus provide for: a rectification circuit operating to convert a source of AC power into a final DC power source; a rectification filtering capacitance operating to at least partially smooth a voltage of the final DC power source, which exhibits a voltage sag and recovery characteristic in response to time-variant current drawn therefrom; a power amplification circuit drawing power from the final DC power source and producing an output signal, for driving a speaker, having audible characteristics influenced by the voltage sag and recovery characteristic of the final DC power source; and a control circuit operating to continuously vary, in response to user input, one or more parameters of the voltage sag and/or recovery characteristic of the final DC power source.

Abstract: An external audio signal is input to an input terminal which is connected to the first terminal of a first resistor. The first terminal of a second resistor is connected to the second terminal of the first resistor. An operational amplifier is arranged such that its inverting input terminal is connected to the second terminal of the second resistor, and a reference voltage is applied to its non-inverting input terminal. A third resistor is arranged between the output terminal and the inverting input terminal of the operational amplifier. A first diode is arranged between the second terminal of the first resistor and a power supply terminal such that its cathode is on the power supply terminal side. Furthermore, a second diode is arranged between the second terminal of the first resistor and the ground such that its cathode is on the second terminal side of the first resistor.

Abstract: Audio capture based on logarithmic conversion. At least some of the illustrative embodiments are methods including capturing audio represented by an electrical signal, the electrical signal having both positive voltage portions and negative voltage portions. In some cases, the capture is by: performing logarithmic analog-to-digital conversion on the positive voltage portions to create a first plurality of digital values; and performing logarithmic analog-to-digital conversion on the negative voltage portions to create a second plurality of digital values; and storing representations of the first and second plurality of digital values to a storage medium.

Abstract: A sound output apparatus configured to connect to an audio processing apparatus may include a communication interface which receives an audio signal from the audio processing apparatus through a wireless communication; a speaker which outputs the received audio signal; an input unit which receives a user control command; and a controller which controls the communication interface so that the received control command is transmitted to the audio processing apparatus through the communication interface.

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: Provided are loudspeaker systems. Embodiments include a first speaker to provide a direct radiating output from the front of the loudspeaker system and a second speaker to drive a ported side chamber of the loudspeaker system, wherein the first and second speakers share a ported common chamber, and wherein at least one port of the ported common chamber exits the front of the loudspeaker system. In one embodiment, the common chamber includes at least one port that is substantially aligned with the front of the loudspeaker system. In another embodiment, each speaker is coupled to a separate amplifier and signal processing unit.

Abstract: The present disclosure provides an audio signal amplifying circuit for an electronic device including a processing chip and a speaker. The audio signal amplifying circuit includes an amplifying circuit and an inverting circuit connected to the processing chip to get a first control signal and invert the first control signal to generate a second control signal. The first control signal and/or the second control signal are used to control the operation mode of the amplifying circuit to be in an amplifying mode or in a non-amplifying mode.

Abstract: An interface circuit is provided that is adapted to connect a microphone circuit to a preamplifier. The microphone circuit has a microphone and at least an output node and the preamplifier has at least an input node connected to the output node by the interface circuit. The interface circuit has at least a decoupling capacitor for DC decoupling the input node from the output node. The decoupling is connected between the input node and the output node. The interface circuit has at least one active circuit, comprising a resistor connected the decoupling capacitor. The resistor acts as part of a resistance multiplier and has an equivalent resistance that together with the decoupling capacitor defines a high-pass filter connected between the microphone and the preamplifier. The interface circuit may also have a biasing circuit connected to the resistor.

Abstract: A signal processing system for use in a multi-channel audio system having a plurality of power amplifier channels connected to a plurality of loudspeakers and power amplifiers, configured to receive and reproduce audio signals through the loudspeakers, and at least a first channel of the plurality of power amplifier channels amplifying a first audio signal, comprises a processor responsive to a signal level threshold applicable to at least said first channel, such that at and above the signal level threshold, the first audio signal in the first channel is amplitude limited and a portion of at least the first audio signal is mixed into at least a second channel. The amplitude limiting and signal mixing is configured so as to reduce introduction of at least one of: a) audible tonal distortion; and b) perceivable spatial distortion; of a sonic presentation due to said limiting and signal mixing.

Abstract: There is disclosed a microphone, a circuit, and a method. A microphone capsule may include an electret microphone and a field effect transistor (FET). A floating DC voltage source may have a first end connected to a drain terminal of the electret microphone capsule and a second end. A load resistor may be connected between the second end of the floating DC voltage source and a source terminal of the electret microphone capsule. A voltage follower may have an output connected to the source terminal of the electret microphone capsule and the first end of the floating DC voltage source. A coupling capacitor may couple an audio signal from the source terminal of the electret microphone capsule to an input of the voltage follower.

Abstract: An audio amplifier includes a compensation unit, an output unit and a calibration unit. The compensation unit generates a compensation signal based on a digital input signal, a digital reference code, a mode signal and a digital approximation code. The output unit generates an output signal based on the compensated input signal. The calibration unit generates the digital approximation code based on the output signal and the mode signal. The digital approximation code includes a plurality of bits that are generated sequentially.

Abstract: A method and apparatus for automatic gain control of an amplifier in which the method and apparatus detects excessive increase in the sound volume or temperature rise in the audio system and reduces the gain of the amplifier by various means. Each gain control circuit has a comparator to compare a signal with threshold values and an integrator to integrate output signals of the comparator with respect to a predetermined time length to reduce a gain of the amplifier. The method and apparatus conducts dynamic suppressing of excess signals and thereby controlling output level of the amplifier at multiple stages without immediately shutting down the audio system. In the case where the sound volume increases to a degree that may damage the amplifier or speaker, a shutdown signal is generated to shutdown the operation of the whole system.

Abstract: Described herein is a preamplifier circuit for a capacitive acoustic transducer provided with a MEMS detection structure that generates a capacitive variation as a function of an acoustic signal to be detected, starting from a capacitance at rest; the preamplifier circuit is provided with an amplification stage that generates a differential output signal correlated to the capacitive variation. In particular, the amplification stage is an input stage of the preamplifier circuit and has a fully differential amplifier having a first differential input (INP) directly connected to the MEMS detection structure and a second differential input (INN) connected to a reference capacitive element, which has a value of capacitance equal to the capacitance at rest of the MEMS detection structure and fixed with respect to the acoustic signal to be detected; the fully differential amplifier amplifies the capacitive variation and generates the differential output signal.

Abstract: A power supply for limited power sources and an audio amplifier using the power supply comprising power sources to provide an output power signal that can be used by load with a high peak to average power requirement ratio. When such power sources are used to power devices that have a high peak to average power consumption, the average power output of the device is severely limited if the peak power is kept below the power supply limits of the limited power source.

Abstract: The teachings are directed to a power amplifier expansion card (“amplifier card”) for a computer. The amplifier card receives audio data through an input port and amplifies the audio data to high-level passive speaker power for transmissions through an output port. The amplifier card can comprise a circuit board having (i) at least two audio channels; (ii) an audio power amplification circuit for amplifying audio power to at least 20 W RMS per channel; and (iii) an onboard cooling system. The amplifier card can be used, for example, in a multimedia system having at least a studio controller operably connected to the amplifier card for receiving and processing input audio data. Examples of such multimedia systems include, but are not limited to, a television home entertainment system, an audio home entertainment system, a music production studio system, a gaming system, a personal computing system, or any combination thereof.

Abstract: Arrangement and method for controlling the order and selection of audio effect components using of a user-controlled crosspoint switch device. A user interface controls a processor which in turn controls the crosspoint device to set a plurality of switches forming a matrix therein, thereby allowing arbitrary control over the order and selection of audio effect components, such as pedals, connected to the matrix. The user interface enables both the pre-programming of the desired effect orders and selections as well as selection of preset stored in a memory component in real-time.

Abstract: Provided is a device and method for controlling game motions in a mobile terminal, having an audio processing unit for converting an input sound into a digital sound, a noise level measurement unit for measuring the noise level of the digital sound, and a controller for calculating a motion control level on the motions object corresponding to the measured noise level, and controlling the corresponding motion of the motions object based on the calculated motion control level. Accordingly, the motion control for the motions object of a game can be differentially controlled according to the level of the sound noise such as wind or sound outputted through the mouth of a user without manipulating the key button with fingers.

Abstract: A pulse width modulation (PWM) amplifier includes a first amplifier stage, a second amplifier stage, and a gain module. The first amplifier stage is configured to amplify an analog input signal in the analog and digital domains using a first pulse width modulation (PWM) generator, to provide a first stage output for coupling to a load. The gain module is configured to amplify a quantization error of the first PWM generator by a predetermined gain. The second amplifier stage is configured to spectrally shape and attenuate the amplified quantization error of the first PWM generator using a second PWM generator, to provide a second stage output for coupling to the load.

Abstract: The invention provided a visor including a headband including an adjustable strap; a bill attached to the headband and including an flexible fabric sound speaker integrally formed within the bill; an amplifier including a signal input, the amplifier removeably attached to the headband and coupled to the speaker; and a power supply removeably attached to the headband and coupled to the amplifier. Numerous additional features are disclosed.

Abstract: Adaptive rail power amplifier technology processes an audio signal by feeding the audio signal to the power amplifier to produce an output signal, applying positive and negative power supply voltages centered with respect to the audio signal to the positive and negative power supply rails of the power amplifier, comparing the output signal with the positive and negative power supply rail voltages to produce dynamically varying positive and negative control signals, feeding the positive and negative control signals to positive and negative high current charge pumps and adding supplemental positive and negative voltages from the positive and negative charge pumps to the positive and negative power supply rails to produce a linear adaptive rail voltage which tracks the output signal.

Abstract: According to one embodiment, an electronic apparatus includes a speaker, a terminal, an amplifier, a power supply circuit, a setting module, a detection module, and a controller. The terminal is configured to input an audio signal from an external device. The amplifier is configured to amplify the audio signal, and to output audio from the speaker. The power supply circuit is configured to supply power to the amplifier. The setting module is configured to set data which indicates whether audio output from the speaker is to be enabled or disabled when the apparatus is in a non-operative state. The detection module is configured to detect a predetermined state of the apparatus. The controller is configured to control the power supply circuit, based on the data and the predetermined state, in order to supply the power to the amplifier when the apparatus is in the non-operative state.

Abstract: The present invention provides an apparatus for sound comprising a sound source generating unit for generating an electric signal from a sound source, N (N?2) amplifiers which are connected in series so that the output part of one amplifier is connected with the input part of the other amplifier and one of them is connected with the sound source generating unit, and 2N speakers which are respectively connected with left and right output parts of each of the N amplifiers. According to one aspect of the invention there is formed a multiple stereo imaging including a first stereo imaging, a first mono imaging, a second mono imaging and a second stereo imaging generated by the first mono imaging and the second mono imaging.

Abstract: Aspects of the disclosure process an amplifier circuit. The amplifier circuit includes an input stage, an intermediate stage, an output stage and a detecting and controlling circuit. The input stage is configured to receive an electrical signal for amplification. The intermediate stage is configured to amplify with an adjustable gain. The output stage is configured to drive an audio output device in response to the amplified electrical signal. The detecting and controlling circuit is configured to detect a current for driving the audio output device, and adjust the gain of the intermediate stage based on the current to compensate for a pole change of the amplifier circuit due to a change of the current.

Abstract: A system for processing audio data comprising an amplifier configured to receive an audio signal and to perform nonlinear processing on the audio signal. An encoder coupled to the amplifier, the encoder configured to receive the nonlinearly processed audio signal and to encode the nonlinearly processed audio signal into a data transmission format. A transmitter configured to receive and transmit the encoded nonlinearly processed audio signal. A receiver configured to receive the transmitted encoded nonlinearly processed audio signal and to decode the encoded nonlinearly processed audio signal. A digital voice processor configured to receive the nonlinearly processed audio signal and to use the nonlinearly processed audio signal for echo estimation and to subsequently subtract the estimated echo signal from a microphone signal.

Abstract: A sensor amplifier arrangement includes an amplifier having a signal input to receive a sensor signal and a signal output to provide an amplified sensor signal, and a feedback path that couples the signal output to the signal input and provides a feedback current that is an attenuated signal of the amplified sensor signal and is inverted with respect to the sensor signal.

Abstract: An audio amplifier system may include an audio CODEC/output (AOP) path featuring analog class-D amplifiers, and using Natural Sampling Pulse Width Modulation (PWM) to convert an analog input into a series of Rail-to-Rail pulses. The audio signal may be encoded in the average value of the PWM pulse train and may be recovered from the PWM signal by analog low pass filtering. The Class-D amplifiers may be designed with a negative feedback loop/network to compare the output signal with the input signal and suppress non-idealities introduced by the Class-D switching stage. Furthermore, operation of the AOP may be designed according to a separate signal transfer function and a separate noise transfer function, and 2nd order noise shaping may be performed at low power, with an optimized filter included in the feedback loop to achieve the best noise reduction at low power.

Abstract: An amplification apparatus comprises: an amplifier circuit that amplifies an input audio signal and outputs an output audio signal; a first signal level determining unit that determines whether or not a signal level of the output audio signal outputted from the amplifier circuit is lower than a silence determination reference value; and a power-supply control unit that shifts the amplification apparatus from a power-on state to a power-off state, when it is determined that the signal level of the output audio signal outputted from the amplifier circuit is lower than the silence determination reference value.

Abstract: An apparatus is provided for remotely monitoring a plurality of amplifiers on a display device. The amplifiers are provided to process audio signals and directly or indirectly connected to a network. In the apparatus, a collecting section collects a group code from each of the amplifiers through the network. The group code is allocated to each amplifier according to a grouping system for grouping the plurality of the amplifiers. A display control section displays a tree diagram of the amplifiers according to the collected group codes on the display device as a graphical representation of the grouping system.

Abstract: An audio amplifier apparatus for driving a loudspeaker is provided. The audio amplifier apparatus includes a soft charge unit, a first amplification module, and a second amplification module. The soft charge unit is coupled to the loudspeaker through an output terminal and supplies a driving current according to a first control signal to soft charge the loudspeaker, so as to gradually increase a voltage level on the output terminal. The first amplification module receives an audio signal according to the first control signal and amplifies the audio signal to output a first amplified signal for driving the loudspeaker. The second amplification module receives the audio signal according to a second control signal and amplifies the audio signal to output a second amplified signal for driving the loudspeaker. The soft charge unit generates the second control signal by comparing the voltage level on the output terminal with a predetermined voltage level.

Abstract: A display device has an audio amplifier which amplifies and outputs an audio signal, and first and second isolation transformers which are provided in an electric power transmission path between a power source, which supplies electric power to the display device, and the audio amplifier.

Abstract: Disclosed is a speaker system. The speaker system includes a multimedia unit including a plurality of speaker units, a resonance medium for supporting the multimedia unit, a number of low frequency vibrators assembled with the multimedia unit and located between the multimedia unit and the resonance medium, a driving unit for providing high frequency audio signals to the speaker units and low frequency audio signals to the low frequency vibrators. A resonance member is formed by the low frequency vibrators and the resonance medium for producing low frequency sound.

Abstract: The present invention provides embodiments of a musical instrument preamplifier. It is especially suited to acoustic and electric guitars and basses. All components, including the power source, are contained within or on the body of the instrument. The preamplifier dubbed BPTD (for Battery Powered Tube Driver) contains a vacuum tube input stage and may utilize a second stage consisting of either a vacuum tube or semiconductor device, such as a JFET. Circuitry is included to bias the cathode heater and the preamplifier circuit with no dangerous high voltages present. The tube may be mounted on the instrument body to provide for a pleasing display.

Abstract: An audio signal processing circuit includes a first amplifier to generate a first analog audio signal; a second amplifier to generate a second analog audio signal; an analog/digital converter to generate a first digital audio signal; a digital signal processing unit to output a second digital audio signal; a digital/analog converter to generate differential third analog audio signals; a third amplifier for inverting a positive signal of the third analog audio signals and adding it to a negative signal to generate a single-ended fourth analog audio signal; and a fourth amplifier to generate an output audio signal.

Abstract: Embodiments of the present invention provide methods and devices for controlling a command signal applied to a load. In embodiments of the invention, current through and voltage across a load are determined and the values of both are used to generate a hybrid control signal. For example, in some embodiments the hybrid control signal is generated by taking a weighted summation of the current and voltage control signals. In other embodiments, a percentage of the difference between the current and voltage control signals is added to one of the current or voltage control signals to generate the hybrid control signal. In one embodiment, a potentiometer is used to generate the hybrid control signal.

Abstract: An audio output circuit for driving an electro-acoustic transducer includes first and second D-class amplifiers, a pulse modulator to receive an audio signal and generate first and second pulse signals for driving first and second D-class amplifiers, first and second drivers to drive first and second D-class amplifiers in response to first and second pulse signals, respectively, a common mode choke coil, and a delay setting circuit to apply a relative delay to output signals of the first and second D-class amplifiers