Abstract: The present invention provides a signal processing circuit and a signal processing method applied to a headset. In the present invention, the signal processing circuit adjusts gain and phase of a left channel signal and a right channel signal to generate a first adjust signal, and a recorded sound from a microphone is added by the first adjust signal to cancel a coupled signal. In addition, the signal processing circuit adjusts gain and phase of the right channel signal to generate a second adjust signal, and the right channel signal is added by the second adjust signal to cancel a coupled signal; and the signal processing circuit adjusts gain and phase of the left channel signal to generate a third adjust signal, and the left channel signal is added by the third adjust signal to cancel a coupled signal.

Abstract: A signal processing apparatus includes a speech recognition system and a voice activity detection unit. The voice activity detection unit is coupled to the speech recognition system, and arranged for detecting whether an audio signal is a voice signal and accordingly generating a voice activity detection result to the speech recognition system to control whether the speech recognition system should perform speech recognition upon the audio signal.

Abstract: A digital microphone system, audio control device and control method thereof is related to the method for controlling a digital microphone circuit including receiving a clock signal; detecting that the clock signal is maintained at a predetermined level for a duration; when the duration reaches a given time, switching a transmission type of a data pin; in a data mode, outputting a digital audio signal to a data line via the data pin in an output type; and in a command mode, receiving a command signal from the data line via the data pin in an input type.

Abstract: A signal processing apparatus includes a speech recognition system and a voice activity detection unit. The voice activity detection unit is coupled to the speech recognition system, and arranged for detecting whether an audio signal is a voice signal and accordingly generating a voice activity detection result to the speech recognition system to control whether the speech recognition system should perform speech recognition upon the audio signal.

Abstract: An audio mixing device and method are provided. The audio mixing device includes an analog to digital converter (ADC), a converting module, a mixing module, and a down-sample filter. The ADC is adapted to receive an analog signal, and convert the analog signal into a first digital signal. The converting module receives the second digital signal, and adjusts a data rate of the second digital signal according to a data rate of the first digital signal to generate a third digital signal. The mixing module mixes the first digital signal and the third digital signal to output a mixed signal. The down-sample filters down-samples the mixed to output a down-sampled signal.

Abstract: A signal processing apparatus for generating a noise cancellation signal in accordance with a noise signal includes an inverting circuit and a selecting circuit. The inverting circuit is employed for inverting a first signal to generate an inverted first signal. The selecting circuit is coupled to the inverting circuit, and employed for selecting one of the first signal and the inverted first signal as an output signal.

Abstract: An audio multi-standard detection apparatus is provided to pre-record a plurality of audio broadcasting format carrier bands. The detection apparatus includes: a carrier calculation unit and a switch controller. The carrier calculation unit is used for receiving an intermediate frequency signal and calculates the first carrier energy of the intermediate frequency signal in each of the frequency bands. From this first carrier energy, the switch controller determines which frequency bands are existed in the intermediate frequency signal, then analyzes the signal via at least one threshold value to determine the frequency band's primary carrier. The switch controller obtains an effective carrier. Further, the switch controller compares the effective carrier with the pre-recorded carrier bands for selectively outputting the appropriate audio broadcasting format.

Abstract: A data weighted average circuit is disclosed which includes a lookup unit and a storage unit. The invention uses a lookup table to speed up the circuit operation. Besides, the operation delay is not affected by various orders of the data weighted average circuit and various bit-widths of input data.

Abstract: An audio mixing device and method are provided. The audio mixing device includes an analog to digital converter (ADC), a converting module, a mixing module, and a down-sample filter. The ADC is adapted to receive an analog signal, and convert the analog signal into a first digital signal. The converting module receives the second digital signal, and adjusts a data rate of the second digital signal according to a data rate of the first digital signal to generate a third digital signal. The mixing module mixes the first digital signal and the third digital signal to output a mixed signal. The down-sample filters down-samples the mixed to output a down-sampled signal.

Abstract: An audio multi-standard detection apparatus is provided to pre-record a plurality of audio broadcasting format carrier bands. The detection apparatus includes: a carrier calculation unit and a switch controller. The carrier calculation unit is used for receiving an intermediate frequency signal and calculates the first carrier energy of the intermediate frequency signal in each of the frequency bands. From this first carrier energy, the switch controller determines which frequency bands are existed in the intermediate frequency signal, then analyzes the signal via at least one threshold value to determine the frequency band's primary carrier. The switch controller obtains an effective carrier. Further, the switch controller compares the effective carrier with the pre-recorded carrier bands for selectively outputting the appropriate audio broadcasting format.

Abstract: A digital-to-analog converting (DAC) circuit is utilized for converting a 1-bit stream into an analog output signal. The DAC includes an N-bit encoder, a multiplexer, a low-pass filter, and a digital-to-analog conversion circuit. The N-bit encoder is utilized for receiving the 1-bit stream and encoding the 1-bit stream to generate an N-bit stream, where N is larger than 1; the multiplexer is utilized for selectively outputting the N-bit stream or a zero signal as an output signal according to a selection signal; the low-pass filter is utilized to generate a filtered output signal according to the output signal; and the digital to analog conversion circuit is utilized to generate the analog output signal according to the filtered output signal.

Abstract: A data weighted average circuit is disclosed which includes a lookup unit and a storage unit. The invention uses a lookup table to speed up the circuit operation. Besides, the operation delay is not affected by various orders of the data weighted average circuit and various bit-widths of input data.

Abstract: An amplifier includes a subtracting unit for generating an error signal according to an input signal and an output signal; a noise shaping unit for executing a noise shaping operation on the error signal to produce a noise-shaped signal; a pulse adjustment unit for generating a control signal according to the noise-shaped signal and the input signal; and a power stage for generating the output signal according to the control signal.

Abstract: An audio coding and decoding device, which is used to realize the coding and decoding functions, audio coding and decoding device comprising: a first circuit, which is used to perform the first operation of said audio coding and decoding function; a general-purpose processor, which is used to perform the second operation of said audio coding and decoding function according to an instruction set and a software program; and a serial link, which is coupled between said first circuit and said general-purpose processor, and is used to serially transmitting the data between said first circuit and said general-purpose processor.

Abstract: An amplifier includes a subtracting unit for generating an error signal according to an input signal and an output signal; a noise shaping unit for executing a noise shaping operation on the error signal to produce a noise-shaped signal; a pulse adjustment unit for generating a control signal according to the noise-shaped signal and the input signal; and a power stage for generating the output signal according to the control signal.