A system includes an instrumentation amplifier (INA) including a first transistor coupled to a first input node, and a second transistor coupled to a second input node. The INA also includes a resistor coupled between the first transistor and the second transistor. The INA includes a gain resistor network coupled to the resistor and to the first and second transistors, where the gain resistor network includes two or more gain resistors. The system also includes a voltage to current converter, where the voltage to current converter is coupled to the resistor and the gain resistor network.

A system for controlling the gain of an input signal in an audio signal amplifier. The system includes a user-operable gain control, and analog and digital circuit elements that together are configured to modify the gain of the input signal in response to the user-operable gain control.

A variable gain amplifier includes a first transconductor circuit coupled to a first input terminal, a first output terminal, and a second output terminal of the variable gain amplifier, the first transconductor circuit including: a plurality of positive coefficient transistors coupled to the first output terminal and configured to selectively conduct current in response to a first binary code, a plurality of negative coefficient transistors coupled to the second output terminal and configured to selectively conduct current in response to a second binary code, and a plurality of amplifying transistors, each having a gate electrode coupled to the first input terminal, a first electrode coupled to a ground reference, and a second electrode coupled to a pair of coefficient transistors including one of the plurality of positive coefficient transistors and one of the plurality of negative coefficient transistors.

Disclosed embodiments provide flexible performance, high dynamic range, microelectromechanical (MEMS) multipath digital microphones, which allow seamless, low latency transitions between audio signal paths without audible artifacts over interruptions in the audio output signal. Disclosed embodiments facilitate performance and power saving mode transitions maintaining high dynamic range capability.

An apparatus for providing an output signal to an audio transducer comprises: one or more signal paths for receiving respective digital audio input signals, applying respective digital gains, and outputting respective amplified digital audio input signals; one or more inputs for receiving one or more volume parameters associated with the digital audio input signals; converter circuitry, coupled to the one or more signal paths, for converting the one or more amplified digital audio input signals into the analogue domain, and outputting an analogue audio input signal; an analogue gain element, for applying an analogue gain to the analogue audio input signal and outputting the output signal; and a control circuit, coupled to the one or more signal paths, operative to select the analogue gain based on a comparison of the volume parameters and the one or more digital audio input signals as multiplied by the volume parameters, and to select the respective digital gains for each digital audio input signal so that an overall gain in the respective signal path corresponds to a volume parameter associated with the respective digital audio input signal.

A guitar holder with a built-in guitar amplifier for enabling convenient guitar practice and/or play with a compact, space-saving footprint. The guitar holder may comprise any of a variety of guitar holders, including but not limited to a guitar stand and/or a guitar wall hanger.

A semiconductor integrated circuit includes an equalizer circuit configured to amplify a signal component in a particular frequency band of an input signal on a signal path after a coupling capacitor, a sampler circuit configured to convert a first signal outputted from the equalizer circuit to a digital signal, a detector circuit configured to output a second signal based on a frequency of appearance of two values included in the digital signal, and a compensator circuit configured to compensate for a shift of a DC voltage level on the signal path after the coupling capacitor based on the second signal outputted from the detector circuit.

A differential amplifier is provided. The differential amplifier includes a first single-ended amplifying means including at least a first terminal and a second terminal, a second single-ended amplifying means including at least a first terminal and a second terminal, a first transmission line, and a second transmission line. In this context, the first terminal of the first single-ended amplifying means is connected to the second terminal of the second single-ended amplifying means via the first transmission line. In addition to this, the first terminal of the second single-ended amplifying means is connected to the second terminal of the first single-ended amplifying means via the second transmission line.

An electronic circuit includes a microcontroller and a DSP (Digital Signal Processor), where the differential of the electronic circuit now proposed, is to transfer the output power to one of the different channels in a free and individual way, from one side to the other, being able to equalize and amplify each channel (speaker), permitting the power division not necessarily equal to said channels.

An audio processing apparatus configured to limit a dynamic range of an audio signal includes a variable gain amplifier configured to generate an output signal by amplifying or attenuating an input signal, a level detector configured to detect a level of the input signal or the output signal, and a gain controller configured to perform an attack and a release based on the level and a plurality of threshold values.