Devices, systems, and methods for multi-channel common-mode coupled alternating current (AC) gain amplifiers (MC-CM-AC Amp) are disclosed. The MC-CM-AC Amp can comprise a first operational amplifier including: a first non-inverting input port configured to be coupled to a first input signal, and a first inverting input port configured to be coupled to a first capacitor. The MC-CM-AC Amp can comprise a second operational amplifier including a second non-inverting input port configured to be coupled to a second input signal, and a second inverting input port configured to be coupled to a second capacitor. The MC-CM-AC Amp can comprise one or more gain-setting resistors configured to be coupled between the first capacitor and the second capacitor.

Devices, systems, and methods for multi-channel common-mode coupled alternating current (AC) gain amplifiers (MC-CM-AC Amp) are disclosed. The MC-CM-AC Amp can comprise a first operational amplifier including: a first non-inverting input port configured to be coupled to a first input signal, and a first inverting input port configured to be coupled to a first capacitor. The MC-CM-AC Amp can comprise a second operational amplifier including a second non-inverting input port configured to be coupled to a second input signal, and a second inverting input port configured to be coupled to a second capacitor. The MC-CM-AC Amp can comprise one or more gain-setting resistors configured to be coupled between the first capacitor and the second capacitor.

Gain is suppressed. In a power amplification circuit, a first transistor has a first input terminal, a first output terminal, and a first ground terminal. A second transistor has a second input terminal, a second output terminal, and a second ground terminal. The second input terminal is connected to the first input terminal. The second output terminal is connected to the first output terminal. A first bias circuit is connected to the first input terminal. A second bias circuit is connected to the second input terminal. A first resistor is connected between the first ground terminal and the ground. A second resistor is connected between the second ground terminal and the ground. The second resistor has a resistance value greater than that of the first resistor.

Techniques for optimizing a player based on the addition of a second player are disclosed. In an embodiment, when a first player no longer needs to play certain audio frequencies due to the addition of a second player, the gain of the first player is automatically increased as part of the setup process. In another embodiment, when a first player needs to play certain audio frequencies, for example due to the removal of a second player, the gain of the first player is automatically decreased. Many other embodiments are disclosed.

Techniques for optimizing a player based on the addition of a second player are disclosed. In an embodiment, when a first player no longer needs to play certain audio frequencies due to the addition of a second player, the gain of the first player is automatically increased as part of the setup process. In another embodiment, when a first player needs to play certain audio frequencies, for example due to the removal of a second player, the gain of the first player is automatically decreased. Many other embodiments are disclosed.

A method and an electronic device of controlling an audio output are disclosed. The method includes detecting an audio output device connected to an electronic device, determining a type of audio output device associated with the audio output device connected to the electronic device, determining a first audio output level associated with the audio output device connected to the electronic device based on the type of audio output device and a predetermined audio output level, and outputting an audio output at the first audio output level using the audio output device.

A method and an electronic device of controlling an audio output are disclosed. The method includes detecting an audio output device connected to an electronic device, determining a type of audio output device associated with the audio output device connected to the electronic device, determining a first audio output level associated with the audio output device connected to the electronic device based on the type of audio output device and a predetermined audio output level, and outputting an audio output at the first audio output level using the audio output device.

An electronic device is provided. The electronic device includes a display, communication circuitry, and a processor operatively connected to the display and the communication circuitry, wherein the processor is configured to transmit audio data to an external device through the communication circuitry, receive a user input for adjustment of a volume level of an audio output through the external device, in response to the user input, check whether a first volume level being set in the electronic device is within a specified range, select one of the first volume level of the electronic device or a second volume level of the external device to be adjusted corresponding to the user input based on whether the first volume level being set in the electronic device is within the specified range, display a volume panel UI comprising the selected one of the first volume level or the second volume level and a graphic object indicating the one of the electronic device or the external device, when adjusting the selected one of the first volume level or the second volume level, and change the graphic object indicating the selected one of the electronic device or the external device to a graphic object indicating other of the electronic device or the external device and switch the selected one of the first volume level or the second volume level to other of the first volume level or the second volume level to be adjusted corresponding to the user input, when adjusting the other of the first volume level or the second volume level while displaying the volume panel UI.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.