Abstract: An apparatus capable of performing acoustic echo cancellation and a method thereof are provided. The apparatus comprises a mapping matrix, first and second speakers, first and second microphones, a reference generator, and a multi-channel acoustic echo canceller. The mapping matrix generates an output signal according to the first and second far end signals. The first and second speakers, coupled to the mapping matrix, play the output signal. The first and second microphones receive the first and second echo signals that are acoustically coupled from the first and second speakers to the first and second microphones, wherein the first and second echo signals are correlated to the output signal. The reference generator generates a reference signal linearly correlated to the output signal according to the first and second far end signals.

Abstract: The invention provides an audio interface device and method utilizing a single audio jack connector for plugging into a three-wire analog microphone or a three-wire digital microphone, thereby reducing dimensions and production costs thereof and an electronic system using the same. The audio interface comprises an audio jack connector, having first to third contacts electronically connected with the three-wire microphone plugged thereinto; and an audio processing device, detecting a type of the three-wire microphone plugged into the audio jack connector, outputting a clock signal to the three-wire microphone and receiving a digital audio signal from the three-wire microphone when the type is digital; or receiving analog audio signals from the three-wire microphone when the type is analog.

Abstract: The invention provides an audio interface device and method to acquire audio signal from either an analog or digital microphone through a common connector. The audio interface comprises a connector, electrically connected with a microphone plugged thereinto, an analog readout circuit, acquiring an analog audio signal from an analog microphone, a digital readout circuit, acquiring a digital audio signal from a digital microphone, and a decision circuit, selectively connecting the analog or digital readout circuit to the connector to acquire the analog or digital audio signal respectively according to whether the microphone plugged into the connector is analog or digital.

Abstract: The invention provides a microphone. The microphone receives a first sound signal and at least one second electrical signal and outputs a third electrical signal. In one embodiment, the microphone comprises a transducer and a signal processor. The transducer converts the first sound signal to a first electrical signal. The signal processor has a first input terminal receiving the first electrical signal and at least one second input terminal receiving the at least one second electrical signal, and derives the third electrical signal from the first electrical signal and the second electrical signal. In one embodiment, the at least one second electrical signal is derived from a t least one second sound signal by at least one second microphone located in the vicinity of the microphone. In another embodiment, the at least one second electrical signal comprises a wind noise signal derived from wind pressure by a pressure sensor located in the vicinity of the microphone.

Abstract: A microphone array comprises a circuit board, a first microphone, and a second microphone. The circuit board comprises a first layer, a third layer, and a second layer sandwiched between the first and third layers. The first layer comprises a first shielding part with a fixed electric potential. The third layer comprises a second shielding part with the fixed electric potential. The second layer comprises an electrically conductive part running between the first and second shielding parts. The first microphone is attached to the first layer of the circuit board. The second microphone is attached to the first layer of the circuit board and electrically connected to the first microphone through the electrically conductive part of the second layer of the circuit board.

Abstract: The invention provides a method for mixing signals with an analog-to-digital converter. The analog-to-digital converter receives a plurality of analog signals. First, the plurality of analog signals are respectively converted to a plurality of first datastreams with a plurality of first delta-sigma modulators. The plurality of first datastreams are then mixed to generate at least one second datastream. The at least one second datastream is then converted to at least one third datastream with at least one second delta-sigma modulator. The at least one second delta-sigma modulator and the plurality of first delta-sigma modulators are triggered by the same clock signal.

Abstract: A microphone module. The module comprises a carrier having a first side and an opposing second side and comprising a through hole. A microphone is disposed on the first side of the carrier and corresponding to the through hole. A processing chip is disposed on the first side of the carrier and coupled to the microphone. An encapsulant is disposed on the first side of the carrier to encapsulate the microphone and the processing chip.

Abstract: An electronic device includes a housing, a plurality of microphones, and a plurality of guide tubes. The plurality of microphones are disposed in the housing. The plurality of guide tubes extend from the housing toward the plurality of microphones, whereby the plurality of microphones in the housing are capable of receiving external sound via the guide tubes.

Abstract: The invention provides a method for mixing signals with an analog-to-digital converter. The analog-to-digital converter receives a plurality of analog signals. First, the plurality of analog signals are respectively converted to a plurality of first datastreams with a plurality of first delta-sigma modulators. The plurality of first datastreams are then mixed to generate at least one second datastream. The at least one second datastream is then converted to at least one third datastream with at least one second delta-sigma modulator. The at least one second delta-sigma modulator and the plurality of first delta-sigma modulators are triggered by the same clock signal.

Abstract: The invention provides a method for mixing signals with an analog-to-digital converter. The analog-to-digital converter receives a plurality of analog signals. First, the plurality of analog signals are respectively converted to a plurality of first datastreams with a plurality of first delta-sigma modulators. The plurality of first datastreams are then mixed to generate at least one second datastream. The at least one second datastream is then converted to at least one third datastream with at least one second delta-sigma modulator. The at least one second delta-sigma modulator and the plurality of first delta-sigma modulators are triggered by the same clock signal.

Abstract: A digital-to-analog converter (DAC) compatible with CMOS technology and operable in low voltage applications. An input capacitor stores a charge sample according to a digital input signal and a previous output analog signal. An analog output circuit has a feedback capacitor to share the charge sample and accordingly generate a current output analog signal from an output node. The output node may be continually connected to the input capacitor through a pass resistor.

Abstract: A method for converting an analog signal to multiple different phase outputs with an analog-to-digital converter is provided. First, the analog signal is converted to a high-frequency datastream with a delta-sigma modulator. A plurality of low-frequency datastreams are then generated by periodically extracting the samples of the high-frequency datastream, wherein consecutively extracted samples of the high-frequency datastream are scattered to different low-frequency datastreams. The low-frequency datastreams have the same sampling rate, and the phases of the corresponding samples of the low-frequency datastreams are different from each other.

Abstract: A low-voltage detection circuit detects a terminal voltage of a power supply terminal. The low-voltage detection circuit includes a first voltage-dividing circuit, a second voltage-dividing circuit, and a comparator. The second voltage-dividing circuit includes a bias circuit and a metal-oxide-semiconductor (MOS) transistor. The comparator compares and receives a voltage generated by the first voltage-dividing circuit and a voltage generated by the second voltage-dividing circuit to generate a voltage detection signal.

Abstract: A DC level wandering cancellation circuit is provided. The DC level wandering cancellation circuit comprises a low pass filter, for receiving an input voltage; a high pass filter coupled to the low pass filter; an amplifier coupled to the high pass filter for receiving a reference voltage and an output signal of the high pass filter; a comparator coupled to the amplifier for receiving an output signal of the amplifier to compare the reference voltage with the output signal of the amplifier; a resistor coupled between outputs of the high pass filter and the amplifier; a control logic coupled to the comparator for receiving a compared result from the comparator; and a switching means coupled between the high pass filter and the output of the amplifier. The switching means is turned on for a predetermined interval by the control logic according to the compared result.

Abstract: A DC level wandering cancellation circuit is provided. The DC level wandering cancellation circuit comprises a low pass filter, for receiving an input voltage; a high pass filter coupled to the low pass filter; an amplifier coupled to the high pass filter for receiving a reference voltage and an output signal of the high pass filter; a comparator coupled to the amplifier for receiving an output signal of the amplifier to compare the reference voltage with the output signal of the amplifier; a resistor coupled between outputs of the high pass filter and the amplifier; a control logic coupled to the comparator for receiving a compared result from the comparator; and a switching means coupled between the high pass filter and the output of the amplifier. The switching means is turned on for a predetermined interval by the control logic according to the compared result.

Abstract: The present invention provides a control circuit with multiple power sources, which accepts an output signal from a comparator circuit. This control circuit with multiple power sources contains two components: one is a voltage transferring circuit, which connects to the comparator and accepts the first and the second input voltages to react the controls of respective output signals for generating the first voltage potential and the second voltage potential; another is an output circuit, which connects to the voltage transferring circuit to react the controls of the first voltage potential and the second voltage potential for deciding the correct output from the first input voltage or the second input voltage.

Abstract: A biasing circuit and a voltage control oscillator thereof are provided. The biasing circuit comprises a compensation circuit, a delay circuit and a comparison circuit. In the biasing circuit, the compensation circuit compensates a first differential voltage that is generated by the delay circuit so as to stabilize an output of the biasing circuit operated by a low-current or low-frequency. The jitter of the clock frequency that the voltage control oscillator output can be reduced.

Abstract: A DC level wandering cancellation circuit is provided. The DC level wandering cancellation circuit comprises a low pass filter, for receiving an input voltage; a high pass filter coupled to the low pass filter; an amplifier coupled to the high pass filter for receiving a reference voltage and an output signal of the high pass filter; a comparator coupled to the amplifier for receiving an output signal of the amplifier to compare the reference voltage with the output signal of the amplifier; a resistor coupled between outputs of the high pass filter and the amplifier; a control logic coupled to the comparator for receiving a compared result from the comparator; and a switching means coupled between the high pass filter and the output of the amplifier. The switching means is turned on for a predetermined interval by the control logic according to the compared result.

Abstract: A low-voltage detection circuit detects a terminal voltage of a power supply terminal. The low-voltage detection circuit includes a first voltage-dividing circuit, a second voltage-dividing circuit, and a comparator. The second voltage-dividing circuit includes a bias circuit and a metal-oxide-semiconductor (MOS) transistor. The comparator compares and receives a voltage generated by the first voltage-dividing circuit and a voltage generated by the second voltage-dividing circuit to generate a voltage detection signal.

Abstract: A biasing circuit and a voltage control oscillator thereof are provided. The biasing circuit comprises a compensation circuit, a delay circuit and a comparison circuit. In the biasing circuit, the compensation circuit compensates a first differential voltage that is generated by the delay circuit so as to stabilize an output of the biasing circuit operated by a low-current or low-frequency. The jitter of the clock frequency that the voltage control oscillator output can be reduced.