Abstract: A POP noise suppression circuit includes a power source terminal, a clock signal input terminal, a charge unit, a discharge unit, a common-mode voltage judging and switching control unit, a charge and discharge capacitor, and a ground terminal. The charge unit includes a first clock generation circuit for generating a first pair of non-overlapped clock signal, and a first equivalent resistor. The discharge unit includes a second clock generation circuit for generating a second pair of non overlapped clock signals, and a second equivalent resistor. The charge unit generates a charge voltage changing slowly to the charge and discharge capacitor. The discharge unit generates a discharge voltage changing slowly to the charge and discharge capacitor. A POP noise suppression system is further provided.

Abstract: Various embodiments are directed to cooperation among communications devices having microphones to employ their microphones in unison to provide voice detection with noise reduction for voice communications. A first communications device comprises a processor circuit; a first microphone; an interface operative to communicatively couple the processor circuit to a network; and a storage communicatively coupled to the processor circuit and arranged to store a sequence of instructions operative on the processor circuit to store a first detected data that represents sounds detected by the first microphone; receive a second detected data via the network that represents sounds detected by a second microphone of a second communications device; subtractively sum the first and second data to create a processed data; and transmit the processed data to a third communications device. Other embodiments are described and claimed herein.

Abstract: A pulse density modulation, PDM, driver, outputs a PDM stream and can be switched to a control token. The switch takes place when the first integral of the PDM stream has a magnitude less than or equal to a first predetermined value and the second integral of the PDM stream has a magnitude less than or equal to a second predetermined value.

Abstract: Methods and systems for cancelation of table noise in a speaker system used for video or audio conferencing are disclosed. Table noise is cancelled in one embodiment by providing a signal or a message whenever a key is depressed on a keyboard or a mouse is clicked. When the key depression signal or message is received, the system evaluates whether speech is occurring. If speech is not occurring, then the microphone in the system is muted. However, if speech is occurring, the microphone is not muted for a period of time to allow the speech to be transmitted to the far end. This allows the conference to be continued in the presence of keyboard sounds if speech is occurring at the same time but also silences the keyboard sounds if speech is not occurring.

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: Methods and systems utilizing seismic sensors configured or designed for use in seismic signal detection are provided so as to reduce the occurrence of spurious responses of the sensors. A method of seismic surveying using a seismic sensor may include the steps of deploying the seismic sensor at a location for seismic signal detection and acquiring seismic signals. The seismic signals may include high frequency response signals containing spurious response signals at an identifiable bandwith. The method may further include applying spurious response cancellation based on the bandwidth location of the spurious response signals and generating modified seismic waveforms having extended frequency bandwidth.

Abstract: A switch can be configured to receive a first signal at a first input and provide an output signal at an output, depending on a state of the switch. A switch state change can be delayed until an indication of a requested switch state different than a current switch state is received and the first signal reaches a threshold.

Abstract: A grounding switch is described which operates properly even in the presence of negative voltages on a signal line. The grounding switch uses isolated field effect transistors that have their substrates tied to different voltages. The isolated field effect transistor has a gate voltage and substrate voltage which can be pulled down to a negative voltage when the signal line has a negative voltage allowing the switch to remain open even with a negative voltage.

Abstract: A consumer electronic product (e.g., a portable media player ported to a media delivery accessory) is powered by a limited capacity DC power source (such as a battery or mini-fuel cell). The consumer electronic product limits the maximum allowable sound pressure level (SPL) that can be produced by the speakers. In one embodiment, the maximum allowable SPL is based upon an amount of stored energy available in the limited capacity DC power source.

Abstract: An electronic device capable of audio files with different formats includes a power supply, a switching circuit, an audio control module, an audio output module, and a detecting module. The power supply supplies a first voltage and a second voltage. The detecting module detects whether the format of the audio file is changed. The detecting module generates a first detecting signal within a first predetermined time period from a point in time when the format of the audio file is changed time point, and the switching circuit transmits the first voltage to the audio control module in response to the first detecting signal. The audio control module receives the second voltage and generates a first signal based on the first voltage and the second voltage. The audio output module is disabled from outputting audio signal of the audio file.

Abstract: A noise elimination circuit of a computer includes a switch and a converting chip. The switch includes first, second, and third electrodes. The first electrode is connected to a control terminal and the third electrode is connected to a first voltage source. The converting chip includes an input pin and an output pin. The input pin is connected to a second voltage source. The output pin is connected to a control chip that controls a speaker. The output pin is connected to the second electrode. The second voltage source powers on the input pin when the computer is triggered to be powered on and powers off the input pin when the computer is triggered to be powered off. The control terminal sends a control signal to the first electrode to actuate the switch, after the computer is triggered and before the second voltage source powers on the input pin.

Abstract: A noise elimination circuit, includes an audio chipset configured to process an audio data file, a power supply unit, a loudspeaker, and a ground circuit. The power supply unit is connected to the sound card and provides power to the audio data file. The audio chipset generates an analog signal when the power supply unit stops providing power to the audio data file. The loudspeaker is connected to the audio chipset via a transmission line. The ground circuit is connected to the transmission line. The ground circuit is turned on to transmit the analog signal to ground when power supply unit stops providing power to the audio data file.

Abstract: Embodiments of the present invention include methods and apparatuses for adjusting audio content when more multiple audio objects are directed toward a single audio output device. The amplitude, white noise content, and frequencies can be adjusted to enhance overall sound quality or make content of certain audio objects more intelligible. Audio objects are classified by a class category, by which they are can be assigned class specific processing. Audio objects classes can also have a rank. The rank of an audio objects class is used to give priority to or apply specific processing to audio objects sin the presence of other audio objects of different classes.

Abstract: A method for reducing audible noise of a power supply provides a PWM signal for controlling a power converter. First, a feedback voltage is produced by detecting an output voltage of the power converter. Afterward, a burst-in voltage and a burst-out voltage are set. Afterward, a voltage level of the burst-in voltage or a voltage level of the burst-out voltage is dynamically varied. Afterward, the PWM signal is switched off when the feedback voltage is less than the burst-in voltage. Final, the PWM signal is switched on when the feedback voltage is greater than the burst-out voltage.

Abstract: A method of operating a microphone system includes providing first and second microphones associated with a same human speaker. An analog ambient noise signal is received from the first microphone. An analog speech signal is received from the second microphone. The analog ambient noise signal is converted into a digital ambient noise signal. The analog speech signal is converted into a digital speech signal. Digital noise cancellation is performed on the digital speech signal dependent upon the digital ambient noise signal. The digital noise cancellation is performed by digital circuitry. The noise canceled digital speech signal is inputted into an intercom system. A low power condition of the microphone system and/or a failure of the digital circuitry is sensed. In response to the sensing step, an analog-based intercom signal is inputted into the intercom system. The analog-based intercom signal is dependent on the analog speech signal and substantially independent of the analog ambient noise signal.

Abstract: When a switching amplifier transitions into a power-off state, a switch is turned off and a power supply controller forcibly discharges a capacitor and forcibly reduces a reference potential with respect to a second power supply voltage. Since a logic power supply voltage reduces by the same amount as the reference potential, the logic power supply voltage from a viewpoint of the reference potential is fixed. A constant current circuit reduces a constant current according to the reduction in the reference potential with respect to the second power supply voltage, and reduces a first electric current and a second electric current. Before the logic power supply voltage from the viewpoint of the reference potential reduces, the first electric current and the second electric current are reduced, and an operation of a pulse generating unit can be ended in a normal state.

Abstract: An exemplary anti-pop circuit for use in an electronic device includes a switch module, a first path module, and a second control module. The first path module outputs a first response signal when the electronic device is being started, the switch module cuts off the connection between the audio IC and the speaker in response to the first response signal. The second control module includes a charge/discharge unit and a second path module. The charge/discharge unit is charged by the DC power supply when the electronic device is being started, and discharges to the second path module when the electronic device is being shut down. The second path module outputs a second response signal when the electronic device is being shut down, the switch module cuts off a connection between the audio IC and the speaker in response to the second response signal.

Abstract: Mute intervals of an audio signal are concealed by decreasing a user's perception of missing audio information. During the mute interval, different concealment techniques are activated at different times to form a concealment signal. The concealment signal is applied to the processed audio signal during the mute interval. A concealment technique may process buffered audio samples before the mute interval in order to obtain the concealment signal. Also, a previously activated concealment generator may be phased out while the currently activated concealment generator may be phased in during a transition period of a mute interval. Different concealment techniques may be used to generate a concealment signal, including a periodic extension concealment technique, a reverberation concealment technique, and a spectral replication technique. Further, the power levels may be matched between different periods of a mute interval.

Abstract: A mute drive circuit includes a micro-controller including an I/O port; a mute circuit; and an npn transistor. When an electronic device using the mute circuit is plugged into an AC power source, the I/O port is set to the logic low, the mute circuit performs the mute mode. When the electronic device is turned on, the I/O port is controlled set to the logic low for a period and then be pulled up to the logic high, the mute circuit performs the mute mode for the period and then enters into the normal mode. When the electronic device is turned off, the I/O port is controlled to set to the logic low, the mute circuit performs the mute mode. When the electronic device is unplugged from the AC power source, the I/O port is pulled down to the logic low, the mute circuit performs the mute mode.

Abstract: A mobile device has an acoustic shock prevention circuit and prevents an acoustic shock unexpectedly occurring when receiver signals and speaker signals are output through a receiver-integrated speaker. The acoustic shock prevention circuit is preferably disposed between the receiver-integrated speaker and an audio processing unit is enabled in a receiver mode and disabled in a speaker mode. When the audio processing unit outputs audio signals partly exceeding a given output range, the enabled acoustic shock prevention circuit removes the exceeded parts of the audio signals.

Abstract: A click-noise suppression system having MOSFET transistor switches positioned between the preamplifiers and coupling capacitors of an audio system wherein the suppression system maintains the switches off when the system is turned on until a charging circuit increases the gate voltage of the switches. The switches quickly turn off and the coupling capacitors are discharged through discharge resistors when the system is turned off.

Abstract: A grounding switch is described which operates properly even in the presence of negative voltages on a signal line. The grounding switch uses isolated field effect transistors that have their substrates tied to different voltages. The isolated field effect transistor has a gate voltage and substrate voltage which can be pulled down to a negative voltage when the signal line has a negative voltage allowing the switch to remain open even with a negative voltage.

Abstract: A speaker control method includes steps of detecting whether there is any audio signal input; outputting a first voltage signal if there is no audio signal input; outputting a second voltage signal if there is an audio signal input; and selectively turning off an audio amplifier according to the first voltage signal or turning on the audio amplifier according to the second voltage signal, wherein the audio amplifier is used for driving a speaker.

Abstract: A digital offset is combined with an audio signal in the digital domain to cancel an output offset caused by one or more analog components processing the same audio signal. In this manner, the offset at the output of the audio signal path (e.g., at a power amplifier output) is reduced or eliminated. Consequently, audible artifacts, such as click-and-pop artifacts, can be reduced or eliminated. In audio devices operating in ground-referenced capless mode, power consumption is reduced because of reduced or eliminated direct current (DC) leakage current through speakers or headsets of such audio devices. In some circumstances, the digital offset in the digital domain may be applied at substantially all times of operation of the audio signal path.

Abstract: A method for providing a mute control function in a computer having multiple microphones is disclosed. A set of mute state information is stored in a control table of a portable computer. The mute state information is for controlling a mute state. Device identifiers (IDs) of all microphones that are connected to the portable computer are registered with the control table. The microphones corresponding to the device IDs registered in the control table are controlled to be in the same mute state based on the mute state information. In response to a detection of an activation of the mute button, the mute state information are inverted. The device IDs registered in the control table are to be controlled in the same mute state based on the inverted mute state information.

Abstract: An audio amplifier includes a timing control circuit, an amplifying circuit, and a bias control circuit. The timing control circuit generates a first power down signal and a second power down signal, in which the first power down signal is asserted before the second power down signal is asserted. The amplifying circuit receives a bias voltage to amplify an audio signal and is deactivated when the first power down signal is asserted. The bias control circuit provides the bias voltage for the amplifying circuit and is deactivated when the second power down signal is asserted.

Abstract: A noise reducing circuit includes a variable low-cut filter disposed at an upstream of a sound signal switching section and has a variable cutoff frequency, and a control circuit which controls the cutoff frequency of the variable low-cut filter to a first cutoff frequency lower than a cutoff frequency of a low-cut filter disposed at downstream of the variable low-cut filter when a switching instruction is not issued from a switching instructing section, and increases the cutoff frequency of the variable low-cut filter to a second cutoff frequency higher than the first cutoff frequency when the switching instruction is issued. The switching of the sound signal switching section is executed after a predetermined period elapses since the switching instruction is issued, and the control section decreases the cutoff frequency of the variable low-cut filter to the first cutoff frequency after the switching of the sound signal switching section is completed.

Abstract: A mobile communication terminal is provided including an audio processing unit, a speaker, a connecting unit that connects to an external audio output device and indicates whether the external audio output device is connected, and a control unit configured to, while in a silent mode, control the audio processing unit to reproduce a music file and to output audio signals, corresponding to the reproduced music file, through the speaker, the silent mode being a mode wherein a vibration signal is generated upon receiving an incoming call, if the external audio output device is connected to the connecting unit, output the audio signals to the external audio output device, and if the external audio output device is disconnected from the connecting unit while the audio signals are being output to the external audio output device, control the display unit to display a user interface for continuing reproduction of the music file.

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: An audio processing device is provided. The audio processing device includes a shaper. The shaper receives a digital input audio signal and generates an output audio signal at an output terminal according to the digital input audio signal. The shaper includes a gain adjustment unit and a shaping unit. The gain adjustment unit receives the digital input audio signal and adjusts the digital input audio signal to generate a gained audio signal. The shaping unit receives the gained audio signal. When the shaper operates in a first mode, the shaping unit shapes an envelope of the gained audio signal to generate a shaped audio signal, and the shaped audio signal serves as the output audio signal.

Abstract: An audio amplifier and a method of operating such an amplifier are disclosed. The audio amplifier includes a switch disabling controller and/or an output set-point controller. The switch disabling controller is configured to disable switching of an output switch circuit or other switch circuit while an input signal represents at least relative silence. The output set-point controller is configured to bring and/or hold first and second switch nodes toward and/or at a set-point voltage while the input signal represents at least relative silence.

Abstract: A signal processing apparatus includes: clip detector means that detects presence/absence of a clipped part with a deformed waveform in each of N audio signals output from N microphones (where N is an integer equal to or greater than 2) based on a dynamic range of a circuit; and interpolation means that treats an audio signal in the N audio signals which has the clipped part detected by the clip detector means as an interpolation target, and other audio signals as non-interpolation targets, and interpolates the waveform of the clipped part of the interpolation target using the waveform of at least one audio signal in the non-interpolation targets.

Abstract: An acoustic shock protection method and device are provided. A pattern analysis-based approach is taken to an input signal to perform feature extraction. A parameter space is identified, which is corresponding to, the signal space of the input signal. A rule-based decision approach is taken to the parameter space to detect an acoustic shock event. The device may be advantageously implemented using a weighted overlap-add approach to provide low group delay, high-fidelity and a high degree of protection from acoustic shock events.

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: A method for selecting an audio data source for a multimedia device includes detecting an error state of audio data for generating a detection result, wherein the audio data is generated by a digital source of the multimedia device, generating an initial counting value, generating a counting result according to the detection result and the initial counting value, confining the counting result within a boundary for generating a limit result, and comparing the limit result with a threshold for generating a comparison result, for selecting the audio data source of the multimedia device.

Abstract: Feedback is reduced by routing an input signal through a kick gate that opens for a predetermined time period then closes. The gate may be kept closed for a predetermined minimum time period before being allowed to open again. The gate is triggered open based on the input signal and may include a plurality of triggering conditions.

Abstract: Disclosed are advances in the arts with novel and useful electronic circuitry with pop and click noise reduction. A load circuit is connected with a full or single-ended half-H bridge circuit and another circuit mechanism in a configuration by which a signal may be used to selectably bring the load circuit terminals to a selected voltage level when an externally applied signal is not present.

Abstract: A system, method, and program product are provided for filtering sound from a selected application on a computer without interrupting voice communications on the computer. The method comprises: monitoring a selected program for an outgoing digital audio signal from a selected application; detecting said digital audio signal; and filtering an analog microphone input with the digital audio signal.

Abstract: A POP noise suppressing circuit includes a blocking capacitor, an outputting element connected to the blocking capacitor, a current generating unit, a charging unit connected to the current generating unit, a discharging unit connected to the current generating unit, a switching unit connected to the charging unit and the discharging unit and a power amplifying unit connected between the switching unit and the blocking capacitor. The current generating unit provides two slowly increasing currents respectively to the charging unit and the discharging unit. The switching unit is for switching between the charging unit and the discharging unit. The charging unit forms a charging current. The discharging unit forms a discharging current. The voltage of the blocking capacitor increases smoothly in a process of powering on and decreases smoothly in a process of powering off. A POP noise suppressing method is also provided.

Abstract: An approach is provided that receives a sound request from a requesting process. A selective mute setting is identified that corresponds to user enablement actions. If the selective mute setting is disabled the sound request is played at an audio output in response. However, if the selective mute setting being enabled, then steps are performed to determine whether to play the sound request. These steps include determining whether the sound request corresponds to one or more user sound request actions. If it is determined that the sound request corresponds to at least one of the user sound request actions then the sound request is audibly played at the audio output. However, if the sound request does not correspond to at least one of the user sound request actions, then the audio request is suppressed and not played at the audio output.

Abstract: Mute circuits capable of eliminating audible noise when the audio system is powered up and powered down are disclosed. A discharge element is coupled between an audio processing unit and an audio output unit in an audio system and a mute control unit is coupled to the discharge element. The mute circuit comprises an active element comprising a control terminal coupled to at least one power voltage at a power terminal of a functional element in the audio processing unit through a capacitor and turning on, by AC capacitor coupling, to drive the discharge element when the audio system is powered up, such that the discharge element is turned on to discharge an output current of the audio processing unit to a ground terminal, thereby muting the audio output unit to eliminate audible noise.

Abstract: A playback device includes: a playback portion that plays back content and outputs at least an audio signal; an acquisition portion that acquires an external audio signal; a generating portion that, based on noise collected by a sound collecting device, generates a noise cancellation signal to reduce the noise; a switching portion that, if the acquisition portion has acquired the external audio signal when the playback portion is playing back content, switches an output signal from the audio signal to the external audio signal; and a synthesizing portion that synthesizes the output signal from the switching portion with the noise cancellation signal.

Abstract: An electronic device includes an amplifier, an output unit, a processing unit, and a mute control circuit. The amplifier is for amplifying audio signals and generating amplified audio signals accordingly. The amplifier includes an output port to output the amplified audio signals. The output unit is for emitting sounds corresponding to the amplified audio signals. The processing unit is for generating a mute control signal. The mute control circuit includes a main circuit and an auxiliary circuit. The main circuit is for responding to the mute control signal, and for driving the amplifier to change between a mute state and a play state accordingly. The auxiliary circuit is for enabling the output port of the amplifier to be electrically grounded at the moment of supplying power to the electronic device.

Abstract: A driver controller comprising a state machine for controlling transitions between a plurality of states. An output switch for providing a low impedance path to ground during transition periods. An output stage for decoupling output signal from driver amplifier during the transition periods.

Abstract: An interference signal removing apparatus of a radio frequency (RF) receiver includes a low noise amplification unit which performs low noise amplification, a feedback processing unit which removes a necessary signal in a desired band from a signal output from the low noise amplification unit, and performs feedback of the signal from which the necessary signal is removed, and a signal processing unit which transmits a processed RF signal by synthesizing an input RF signal and the feedback signal to the noise amplification unit.

Abstract: An electronic audio device with a digital audio output channel in which an amplifier output voltage is gradually ramped up and down to avoid causing a popping sound when the device is turned on and off. This is accomplished without employing any additional hardware, by incrementally changing a digital input word applied to a digital audio source, such as a DSP, so as to gradually change the amplifier output voltage between a minimum, such as zero volts, and a DC working voltage. On powering up, the amplifier is only turned on after the digital word is applied, but while it still results in a minimum amplifier output, and on powering down the amplifier is turned off after it's output has been ramped down, but before removing the digital input word. Sources and output channels can also be switched over by powering down, and then powering up, following the same method.

Abstract: A disclosed system and method dynamically controls the perceived volume of a stereo audio program including left and right channel signals. The system comprises: a dynamic volume control configured and arranged so as to maintain a perceived constant volume level of the stereo audio program; and an excessive spatial processing protection processor configured and arranged for controlling the level of a difference signal, created as a function of the right channel signal subtracted from the left channel signal (L?R), relative to the level of a sum signal, created as a function of the right channel signal plus the left channel signal; wherein the excessive spatial processing protection processor processes the audio signals so as to control the difference (L?R) signal relative to the sum (L+R) signal.

Abstract: An audio amplifier includes a timing control circuit, an amplifying circuit, and a bias control circuit. The timing control circuit generates a first power down signal and a second power down signal, in which the first power down signal is asserted before the second power down signal is asserted. The amplifying circuit receives a bias voltage to amplify an audio signal and is deactivated when the first power down signal is asserted. The bias control circuit provides the bias voltage for the amplifying circuit and is deactivated when the second power down signal is asserted.

Abstract: A de-pop circuit adaptable to an audio circuit is disclosed. A high-pass filter generates a high-pass output signal according to an output signal of the audio circuit. A blockage circuit receives the high-pass output signal and a control signal, and generates an enable signal to activate the audio circuit according to the control signal and the high-pass output signal.