There is provided fiber-coaxial amplifier device (10) comprising at least one output (14) and a test point (26) associated with the at least one output (14), wherein alternative first and second electrical paths (36, 38) are connectable to the at least one output (14), the first path (36) connectable to the at least one output (14) whilst bypassing the test point, the second path (38) connectable to both the at least one output (14) and the test point (26), and a relay (30) operable to connect one of the first path or the second path to the at least one output (14). The fiber-coaxial amplifier device (10) is configured for signals complying with Extended Spectrum DOCSIS.

There is provided fiber-coaxial amplifier device (10) comprising at least one output (14) and a test point (26) associated with the at least one output (14), wherein alternative first and second electrical paths (36, 38) are connectable to the at least one output (14), the first path (36) connectable to the at least one output (14) whilst bypassing the test point, the second path (38) connectable to both the at least one output (14) and the test point (26), and a relay (30) operable to connect one of the first path or the second path to the at least one output (14). The fiber-coaxial amplifier device (10) is configured for signals complying with Extended Spectrum DOCSIS.

Technologies are described to DC-couple an integrated amplifier system to a source that provides a signal with an unknown DC component, for example to DC-couple an integrated audio codec to an analog microphone. In one aspect, methods include receiving, by an amplifier, a signal having an unknown DC component, and issuing an amplified signal; low pass filtering, with respect to a cutoff frequency, by a feedback circuit coupled between an output of the amplifier and an input of the amplifier, the amplified signal issued at the output of the amplifier to generate a filtered signal having frequencies lower than the cutoff frequency; and injecting, by the feedback circuit, the filtered signal into the input of the amplifier to cancel the unknown DC component below the cutoff frequency.

The present invention relates in one aspect to an audio amplification circuit comprising an input terminal for receipt of an input signal from a transducer. A signal processor is operatively coupled to the input terminal for receipt and processing of the input signal to generate a processed digital audio signal in accordance with a programmable configuration setting of the signal processor. A serial data transmission interface is configured for receipt of the processed digital audio signal and supply of a corresponding digital audio stream at an output terminal of the integrated audio amplification circuit. A serial data receipt interface is operatively coupled to an externally accessible configuration terminal of the integrated audio amplification circuit and a controller is configured to adjust one of the programmable configuration setting of the signal processor and a format of a digital audio stream in accordance with first configuration data received through the serial data receipt interface. The controller is in a first state is responsive to a logic state of the externally accessible configuration terminal to control the format of the digital audio stream or the programmable configuration setting. In a second state, the controller is configured for receipt and reading of the first configuration data through the externally accessible configuration terminal and the serial data receipt interface.

Techniques for controlling one or more audio amplifiers in or associated with a device coupled on a local area network are disclosed. An example playback device includes a processor, an amplifier, a network interface, and a memory. The memory includes a software module that, when executed by the processor, causes the playback device to: operate in a first power mode in which the amplifier consumes a first amount of power; while operating in the first power mode, determine that a defined time has passed since receiving, via the network interface, a specified type of data packet; and based on determining that the defined time has passed since receiving the specified type of data packet, transition from operating in the first power mode to operate in a second power mode in which the amplifier consumes a second amount of power, wherein the first amount of power is greater than the second amount of power.

A microphone amplifier unit, to which a microphone of a first form including an LED or a microphone of a second form without including an LED is connected, includes a microphone detecting unit that detects a connection state of the microphone of the first form or the second form based on potential information supplied to a specific terminal pin of a connector. In the microphone amplifier unit, appropriate circuit setting corresponding to functions of the respective microphones is made based on information obtained by the microphone detecting unit. With the configuration, a microphone connecting device that can commonly use the microphone of the first form and the microphone of the second form with a small number of pins is provided.

Techniques for controlling one or more audio amplifiers in or associated with a device coupled on a local area network are disclosed. An example playback device includes a processor, an amplifier, a network interface, and a memory. The memory includes a software module that, when executed by the processor, causes the playback device to: operate in a first power mode in which the amplifier consumes a first amount of power; while operating in the first power mode, determine that a defined time has passed since receiving, via the network interface, a specified type of data packet; and based on determining that the defined time has passed since receiving the specified type of data packet, transition from operating in the first power mode to operate in a second power mode in which the amplifier consumes a second amount of power, wherein the first amount of power is greater than the second amount of power.

Techniques for controlling one or more audio amplifiers in or associated with a device coupled on a local area network are disclosed. An example playback device includes a processor, an amplifier, a network interface, and a memory. The memory includes a software module that, when executed by the processor, causes the playback device to: operate in a first power mode in which the amplifier consumes a first amount of power; while operating in the first power mode, determine that a defined time has passed since receiving, via the network interface, a specified type of data packet; and based on determining that the defined time has passed since receiving the specified type of data packet, transition from operating in the first power mode to operate in a second power mode in which the amplifier consumes a second amount of power, wherein the first amount of power is greater than the second amount of power.

The application describes method and apparatus for amplification. An amplifier circuit (300) is described for driving a load (101) connected between first and second output nodes (103p, 103n) based on an input signal (Sin). The amplifier circuit includes first and second signal paths for generating respective first and second driving signals (Soutp and Soutn) at the first and second output nodes, each of the first and second signal paths comprising a respective sigma-delta modulator (301p, 301n). A correlation controller (302) is configured to control the first and second signal paths to provide correlation between at least some noise components of the first and second driving signals.

A variable voltage phantom power supply assembly includes a phantom power supply unit having a power input, and one or more audio channels. The variable voltage phantom power supply assembly also includes a variable voltage phantom power supply module having a phantom power supply circuit with a variable voltage controller and a variable voltage phantom power output. A method of customizing at least one performance characteristic of a microphone includes: modifying a phantom power supply to provide a variable voltage phantom power output; connecting a microphone to an input of a variable voltage phantom power supply assembly; adjusting the voltage output of the variable voltage phantom power supply to the microphone; monitoring the performance characteristics of the microphone; and, readjusting the voltage output of the variable voltage phantom power supply to the microphone to obtain at least one desired performance characteristic of the microphone.