An electronic device may comprise audio processing circuitry and a universal serial bus (USB) connector having a first contact and a second contact. In a first mode of operation, the audio processing circuitry is configured to output one or more audio signals carrying music and/or voice via the first contact and the second contact. In a second mode of operation, the audio processing circuitry is configured to output a signal for delivering supply current via the first contact and the second contact. While the electronic device is in the first mode of operation, a gain and/or volume limit of the audio processing circuitry may be set to a first level, and while the electronic device is in the second mode of operation, the gain and/or volume limit of the audio processing circuitry may be set to a second level that is higher than the first level.

This disclosure is directed to reducing output voltage distortions of Variable Gain Amplifiers (VGAs). A VGA may include a number of amplifiers each providing a portion of a total gain of the VGA. For example, a processing circuit may select one or more of the amplifiers of the VGA to provide the output signal with a selected gain. However, the selected amplifiers may provide amplified signals with one or more distortion signals when receiving a bias voltage. Systems and methods are described to reduce or cancel the distortion signals of the selected amplifiers by providing a subthreshold nonzero bias voltage (e.g., a weak voltage) to the remaining (e.g., non-selected) amplifiers of the VGA. For example, the non-selected amplifiers may receive the weak voltage to provide distortion signals with similar voltage amplitude and out of phase compared to the distortion signals of the selected amplifiers.

The detection matrix for an Orthogonal Differential Vector Signaling code is typically embodied as a transistor circuit with multiple active signal inputs. An alternative detection matrix approach uses passive resistor networks to sum at least some of the input terms before active detection.

In an embodiment, a class-D amplifier includes an input terminal configured to receive an input signal; a comparator having an input coupled to the input terminal; a deglitching circuit having an input coupled to an output of the comparator; and a driving circuit having an input coupled to an output of the deglitching circuit. The deglitching circuit includes a logic circuit coupled between the input of the deglitching circuit and the output of the deglitching circuit. The logic circuit is configured to receive a clock signal having the same frequency as the switching frequency of the class-D amplifier.

A method for operating a charge pump having a variable switching frequency may include comparing a target minimum output voltage with an output voltage generated at an output of the charge pump and controlling switching of switches of the charge pump based on the comparison such that the variable switching frequency varies as an output current driven by the charge pump varies.

A radio communication device is a radio communication device that performs radio communication by a press-to-talk communication system, and includes an operating unit that receives an operation of a user, an output unit that outputs a received voice signal as a voice, and a volume adjusting unit that adjusts a volume of the voice output by the output unit. The volume adjusting unit acquires source information that indicates a source of the voice signal when a predetermined operation by a user is made with respect to the operating unit, and adjusts the volume of the voice by using an adjustment coefficient that is a degree of adjustment of the volume of the voice, based on the acquired source information.

Systems and methods for a playback device outputting an audio alert from a network-enabled device include (i) while the playback device is playing back audio content, receiving an alert communication from the network-enabled device, the alert communication including (a) an audio notification identifier that identifies an audio notification and (b) a priority identifier that identifies a priority level of the audio notification; (ii) responsive to receiving the alert communication, adding the audio notification to a notification queue at a particular queue position, where the particular queue position of the audio notification in the notification queue is based on the priority level of the audio notification relative to other audio content in the notification queue; (iii) adjusting playback of the audio content for playing back the audio notification; and (iv) the playback device playing back the audio notification.

An electronic device may comprise audio processing circuitry and a universal serial bus (USB) connector having a first contact and a second contact. In a first mode of operation, the audio processing circuitry is configured to output one or more audio signals carrying music and/or voice via the first contact and the second contact. In a second mode of operation, the audio processing circuitry is configured to output a signal for delivering supply current via the first contact and the second contact. While the electronic device is in the first mode of operation, a gain and/or volume limit of the audio processing circuitry may be set to a first level, and while the electronic device is in the second mode of operation, the gain and/or volume limit of the audio processing circuitry may be set to a second level that is higher than the first level.

An example playback device includes a first interface for receiving a first audio signal from a first audio source; a second interface for receiving a second audio signal from a second audio source; and a processor configured to: cause the playback device to playback the second audio signal; determine that the first audio signal is present at the first interface; in response to determining that the first audio signal is present at the first interface, (i) cease playback of the second audio signal being played by the playback device and (ii) cause the playback device to playback the first audio signal; receive an instruction to stop the playback device from playing the first audio signal while the first audio signal is still present at the first interface; and arm the playback device such that a subsequent presence of the first audio signal at the first interface causes the playback device to play the first audio signal.

A car audio output control device and a method therefor are disclosed. When an acoustic source is generated by the peripheral device, the control device controls a car audio output such that when a device acoustic source and an identification code are received while a source acoustic source self-generated by a car audio is outputted, the control device selects one output mode matched with the received identification code from among the plurality of output modes and controls the source acoustic source and the device acoustic source according to the selected output mode so as to change the car audio output.