The present disclosure relates to a method and an apparatus for automatically controlling a gain in an electronic device based on a sensitivity of microphone. The method according to an embodiment of the present disclosure includes outputting a reference audio to a speaker and obtaining a sound signal output by the speaker through a microphone, comparing a parameter of the obtained sound signal with a stored parameter, and adjusting a gain of the microphone based on a result of the comparing.

Extracting a common signal from multiple audio signals may include summing a first signal and a second signal to obtain a first+second signal; subtracting the second signal from the first signal to obtain a first−second signal; transforming the first+second signal and the first−second signal to frequency domain representations; calculating absolute value of the frequency domain representations of the first+second signal and the first−second signal; subtracting the absolute value of the frequency domain representation of the first−second signal from the absolute value of the frequency domain representation of the first+second signal to obtain a difference signal; multiplying the difference signal by the frequency domain representation of the first+second signal to obtain a product signal; dividing the product signal by the absolute value of the frequency domain representation of the first+second signal to obtain a frequency domain representation of the common signal; and transforming the frequency domain representation to the common signal.

An audio signal adjustment method, a storage medium, and a terminal are provided. The method may include: when it is detected that a pre-set event is triggered, controlling a microphone to acquire an audio signal, the pre-set event comprising a pre-set call event and/or a pre-set voice recording event; analyzing the sound loudness corresponding to the audio signal; dynamically adjusting, according to the analysis result and a pre-set adjustment policy, the sound loudness corresponding to the audio signal; and performing, according to the type of the pre-set event, corresponding output processing on the adjusted audio signal.

A front-end amplifier circuit for receiving a biological signal includes a signal channel. The signal channel amplifies the biological signal to generate a detection current and includes a capacitive-coupled transconductance amplifier. The capacitive-coupled transconductance amplifier amplifies the biological signal with a transconductance gain to generate a first current.

A detection device includes a driving circuit which drives a vibrator, and a detection circuit which detects a desired signal. The driving circuit includes a current-voltage conversion circuit which receives a feedback signal, and performs a current-voltage conversion, a drive signal output circuit which amplifies an input voltage signal after being subjected to the current-voltage conversion, and outputs a drive signal of a sine wave, and a gain control circuit which controls a gain of amplification of the drive signal in the drive signal output circuit. When a resistance for a current-voltage conversion is set to RI, the gain of the amplification of the drive signal in the drive signal output circuit is set to K, and an equivalent series resistance in a fundamental wave mode of the vibrator is set to R, the gain control circuit performs a gain control such that K×RI=R is satisfied.

Circuits, devices and methods related to mode-switching of amplifiers. In some embodiments, an audio controller can include a mode state engine configured to receive an enable signal and generate a control signal for controlling a mode transition of an amplifier between a current source mode and a voltage source mode, with the mode transition of the amplifier resulting in an artifact sound. The audio controller can further include an enable component configured to provide the enable signal to the mode state engine based on a masking sound in an audio signal, such that the artifact sound is substantially masked by the masking sound during the mode transition of the amplifier.

Embodiments of the present disclosure disclose a method for recording sound of a video-recorded object and a mobile terminal, so as to reduce background noise in recorded sound of a video-recorded object, and improve quality of the recorded sound. The method in the embodiments of the present disclosure includes: obtaining, by a mobile terminal by means of facial recognition, position information of the video-recorded object; and performing processing on recorded sound signals, so as to enhance signal intensity of a sound signal at a position of the video-recorded object, and attenuate signal intensity of a sound signal at another position, to obtain sound at the position of the video-recorded object.

A portable amplifier is disclosed. In embodiments, the portable amplifier comprises a cabinet that opens and closes on a diagonal to contain all internal components, and optimizes sound quality. In embodiments the portable amplifier can be connected to an extension cabinet in order to provide an additional speaker. The portable amplifier can function on AC or DC power, and features user-friendly lighted ports and controls. The amplifier can feature AINiCo speakers and a three-spring reverb tank. The portable amplifier can be optimized for weight and power to achieve output of about 4 to about 5 watts per pound.

A audio surveillance system includes a pair of headphones. An audio unit is coupled to the pair of headphones and the audio receives a first signal and a second signal. The audio unit records ambient sounds with respect to the headphones thereby facilitating the audio unit to receive the second signal. A control unit is selectively coupled to the headphones and the control unit may be manipulated. The control unit is in electrical communication with the audio unit when the control unit is coupled to the headphones. The control unit adjusts a volume of the second signal with respect to the first signal. Thus, the control unit facilitates a user to monitor the ambient sounds while the user listens to music.

A method performing automatic gain control (AGC) using an accelerometer in a headset starts with an accelerometer-based voice activity detector (VADa) generating a VADa output based on (i) acoustic signals received from at least one microphone included in a pair of earbuds and (ii) data output by at least one accelerometer that is included in the pair of earbuds. The at least one accelerometer detects vibration of the user's vocal chords. The headset includes the pair of earbuds. An AGC controller then performs automatic gain control (AGC) on the acoustic signals from the at least one microphone based on the VADa output. Other embodiments are also described.