The processing of audio signals is shown in which a first gain-adjustable amplifier is configured to receive a feed forward signal from an input and a second gain-adjustable amplifier is configured to receive a feedback signal from an output. A gain controller supplies a first gain control signal to the first gain-adjustable amplifier, wherein the gain controller supplies a complementary second gain control signal to the second gain-adjustable amplifier, which may be the reciprocal of the first gain control signal. A first combiner is arranged to combine a first output from the first gain-adjustable amplifier with a second output from the second gain-adjustable amplifier. A plurality of filter elements are configured in parallel, wherein each filter element receives an output from the first combiner. A second combiner combines outputs from the filter elements with the original input signal and the filter elements have mutually different filtering characteristic.

The processing of audio signals is shown in which a first gain-adjustable amplifier is configured to receive a feed forward signal from an input and a second gain-adjustable amplifier is configured to receive a feedback signal from an output. A gain controller supplies a first gain control signal to the first gain-adjustable amplifier, wherein the gain controller supplies a complementary second gain control signal to the second gain-adjustable amplifier, which may be the reciprocal of the first gain control signal. A first combiner is arranged to combine a first output from the first gain-adjustable amplifier with a second output from the second gain-adjustable amplifier. A plurality of filter elements are configured in parallel, wherein each filter element receives an output from the first combiner. A second combiner combines outputs from the filter elements with the original input signal and the filter elements have mutually different filtering characteristic.

The invention relates to an electrical circuit in the form of a transimpedance amplifier stage, and to a method for operating this circuit. The invention furthermore relates to a circuit containing at least one signal amplifier that has at least one output connection, at least one input connection or at least one pair of differential input connections and at least two voltage supply connections, one of which may also be an earth or ground connection, wherein the signal amplifier has at least one additional connection that is connected internally to at least one of the input connections or the input connection via at least one further component, for example a diode.

A circuit for converting a first voltage to a second voltage in a communication system is disclosed. The circuit includes a pass transistor including a first terminal, a second terminal and a gate, wherein the first terminal is coupled with the first voltage. The circuit is also includes an error amplifier. The error amplifier includes a first input that is coupled with a constant reference voltage and a second input that is coupled with a first switch that is coupled with an output port. A second switch is included and is coupled between the first voltage and an output of the error amplifier. The output of the error amplifier is coupled with the gate of the pass transistor. A third switch is included and is coupled between ground and the output of the error amplifier. The second switch is configured to be driven by a first one shot pulse generated from an input signal of the communication system and the third switch is configured to be driven by a second one shot pulse generated from the input signal.

A system includes a feedforward path coupled to a signal input. The system also includes a speaker coupled to the feedforward path. The system includes a back electromotive force (BEMF) extractor coupled to the speaker, where the BEMF extractor has a first input, a second input, and an output. The BEMF extractor includes a first summing point coupled to the first input. The BEMF extractor includes a resistor amplifier coupled to the second input and the first summing point. The BEMF extractor includes a high pass filter coupled to the second input and to an inductor amplifier. The BEMF extractor also includes a low pass filter coupled to the first summing point. The BEMF extractor includes a second summing point coupled to the low pass filter, the inductor amplifier, and the output.

A signal processing apparatus includes a first signal processing circuit and the second signal processing circuit. The first signal processing circuit receives a first signal. The first signal processing circuit has a power end connecting to a first voltage and a reference ground end. The second signal processing circuit receives a second signal. The second signal processing circuit has a power end which is electrically coupled to the reference ground end of the first signal processing circuit or equals the reference ground end of the first signal processing circuit. The second signal processing circuit has a reference ground end connecting to a second voltage.

A signal processing apparatus includes a first signal processing circuit and the second signal processing circuit. The first signal processing circuit receives a first signal. The first signal processing circuit has a power end connecting to a first voltage and a reference ground end. The second signal processing circuit receives a second signal. The second signal processing circuit has a power end which is electrically coupled to the reference ground end of the first signal processing circuit or equals the reference ground end of the first signal processing circuit. The second signal processing circuit has a reference ground end connecting to a second voltage.

Front end systems and related devices, integrated circuits, modules, and methods are disclosed. One such front end system includes a low noise amplifier in a receive path and a multi-mode power amplifier circuit in a transmit path. An overload protection circuit can adjust an impedance of a switch coupled to the low noise amplifier based on a signal level of the low noise amplifier. The multi-mode power amplifier circuit includes a stacked output stage including a transistor stack of two or more transistors. The multi-mode power amplifier circuit also includes a bias circuit configured to control a bias of at least one transistor of the transistor stack based on a mode of the multi-mode power amplifier circuit. Other embodiments of front end systems are disclosed, along with related devices, integrated circuits, modules, methods, and components thereof.

An integrated circuit includes a transimpedance amplifier and an injection circuit. The injection circuit generates a first electrical test signal and injects the first electrical test signal into the transimpedance amplifier. The first electrical test signal or an output of the transimpedance amplifier generated based on the first electrical test signal is used to determine whether the integrated circuit is faulty.

A gain-controllable magnetoresistive analog amplifier comprises a substrate located in an X-Y plane, an output signal magnetoresistive sensor located on the substrate, and an input signal coil and a gain adjustment coil. The input signal coil and the gain adjustment coil are respectively located on two side surfaces of the output signal magnetoresistive sensor. The gain adjustment coil is used to input a gain signal by the generation of a gain magnetic field, in order to set the gain the magnetic field is applied along a magnetization direction of a free layer of the output signal magnetoresistive sensor, thereby adjusting the slope of the input resistance-magnetic field transfer curve of the output signal magnetoresistive sensor. The input signal coil is used for inputting a current signal to generate an input magnetic field, in order to apply the input magnetic field to a magnetization direction of a pinned layer of the output signal magnetoresistive sensor, thereby controlling the gain signal to adjust a gain factor of an output signal after the current signal passes through the output signal magnetoresistive sensor. This magnetoresistive analog amplifier provides isolation between input signals, output signals, and controllable gain signals.