An audio processor and method of audio processing for an amplifier system is described. The audio processor may receive an audio signal and adapt the audio signal generating a time varying offset. The time varying offset may be combined with the audio signal resulting in a shifted the audio signal level. The processed audio signal may also be clipped to remove the negative samples values. The processed signal may be used to drive an amplifier designed to only accept positive (or negative) signals such as a class C amplifier.

A signal-processing system has an amplifier that generates an amplified (RF) output signal based on an (RF) input signal. The amplifier receives a supply voltage that can be selectively set to an appropriate level between a lower power supply level and a higher power supply level. With one power supply permanently connected to the supply voltage node, a control unit executes software to toggle a supply switch to periodically connect and disconnect the other power supply thereby generating a weighted average value for the supply voltage between the two power supply levels. When a sudden and large increase occurs in the (input) power level, hardware-interrupt circuitry interrupts and supersedes the software-based control of the supply-voltage switch to quickly switch the supply voltage towards the higher power supply level. The hardware-interrupt circuitry handles such situations faster than the software-based control in order to prevent a limit violation of spectrum emission requirements.

A signal-processing system has an amplifier that generates an amplified (RF) output signal based on an (RF) input signal. The amplifier receives a supply voltage that can be selectively set to an appropriate level between a lower power supply level and a higher power supply level. With one power supply permanently connected to the supply voltage node, a control unit executes software to toggle a supply switch to periodically connect and disconnect the other power supply thereby generating a weighted average value for the supply voltage between the two power supply levels. When a sudden and large increase occurs in the (input) power level, hardware-interrupt circuitry interrupts and supersedes the software-based control of the supply-voltage switch to quickly switch the supply voltage towards the higher power supply level. The hardware-interrupt circuitry handles such situations faster than the software-based control in order to prevent a limit violation of spectrum emission requirements.

A circuit may include a control loop to regulate an output of the circuit and a headroom sensing circuit to produce a headroom sensing signal indicative of a headroom voltage of the circuit. The control loop may have a response characteristic that is set based on the headroom signal received from the headroom sensing circuit.

An electronic device may include a speaker, and audio circuitry coupled to the speaker. The audio circuitry may generate digitized samples of an audio waveform signal, and compare each digitized sample of the audio waveform signal to a threshold. The audio circuitry may when a given digitized sample is above the threshold, then apply a compression operation to the given digitized sample and successive digitized samples for a set time period, and when the given digitized sample is below the threshold and not within the set time period, then not apply the compression operation.

An electronic device may include a speaker, and audio circuitry coupled to the speaker. The audio circuitry may generate digitized samples of an audio waveform signal, and compare each digitized sample of the audio waveform signal to a threshold. The audio circuitry may when a given digitized sample is above the threshold, then apply a compression operation to the given digitized sample and successive digitized samples for a set time period, and when the given digitized sample is below the threshold and not within the set time period, then not apply the compression operation.

The present invention related to self-limiting filters, arrays of such filters, and methods thereof. In particular embodiments, the filters include a metal transition film (e.g., a VO.sub.2 film) capable of undergoing a phase transition that modifies the film's resistivity. Arrays of such filters could allow for band-selective interferer rejection, while permitting transmission of non-interferer signals.

The present invention related to self-limiting filters, arrays of such filters, and methods thereof. In particular embodiments, the filters include a metal transition film (e.g., a VO.sub.2 film) capable of undergoing a phase transition that modifies the film's resistivity. Arrays of such filters could allow for band-selective interferer rejection, while permitting transmission of non-interferer signals.

In at least one embodiment, an audio limiter system is provided. The system includes a first limiter block, a second limiter block, and a third limiter block. The first limiter block receives an incoming audio signal having a plurality of first frequencies and limits the incoming audio signal with the plurality of first frequencies based on at least a first gain threshold to generate at least a first high audio output signal. The second limiter block receives the incoming audio signal having a plurality of second frequencies and limits the incoming audio signal with the plurality of second frequencies based on at least a second gain threshold to generate at least a first low audio output signal. The third limiter block receives the first high audio output signal and/or the first low audio output signal and limits the first high audio output signal and/or the first low audio output signal.

In at least one embodiment, an audio limiter system is provided. The system includes a first limiter block, a second limiter block, and a third limiter block. The first limiter block receives an incoming audio signal having a plurality of first frequencies and limits the incoming audio signal with the plurality of first frequencies based on at least a first gain threshold to generate at least a first high audio output signal. The second limiter block receives the incoming audio signal having a plurality of second frequencies and limits the incoming audio signal with the plurality of second frequencies based on at least a second gain threshold to generate at least a first low audio output signal. The third limiter block receives the first high audio output signal and/or the first low audio output signal and limits the first high audio output signal and/or the first low audio output signal.