Example embodiments provide a process that includes one or more of receiving an audio signal at a feedback compressor circuit, multiplying the received audio signal with a power feedback signal to create a product audio signal, wherein the feedback signal comprises a low-pass filtered signal, applying a power amplifier to the product audio signal, and providing the amplified product audio signal as an output signal to a speaker.

A limiter circuit is integrated into an RF power amplifier. The limiter circuit automatically starts adding attenuation at the input of the RF power amplifier after a predetermined input power level threshold is exceeded, thereby extending the safe input drive level to protect the amplifier. In a preferred embodiment of the invention, the limiter circuit is implemented using a pseudomorphic high electron mobility transistor (PHEMT) device or a metal semiconductor field effect transistor (MESPET) device. Diode connected transistors or Schottky diodes may also be used in the limiter circuit.

Radio Frequency (RF) amplifiers with voltage limiting using non-linear feedback are presented herein. According to one aspect, an RF amplifier comprises an amplifier circuit having an input terminal and an output terminal and a non-linear feedback circuit having an input terminal and an output terminal. The input terminal of the non-linear feedback circuit is connected to the output terminal of the amplifier circuit and the output terminal of the non-linear feedback circuit is connected to the amplifier circuit to reduce the gain of the amplifier circuit when an RF voltage swing present at the input terminal of the non-linear feedback circuit exceeds a predefined threshold. In one embodiment, the output terminal of the non-linear feedback circuit is connected to the input terminal of the amplifier circuit. In another embodiment, the output terminal of the non-linear feedback circuit is connected to a bias circuit of the amplifier circuit.

A system and method for enhancing the real and/or perceived bass band of an audio signal is disclosed. A computationally simple yet effective bass band enhancement system for use in consumer electronics applications is disclosed. An audio processing system including bass enhancement functionality for use in a mobile audio system is disclosed.

Improved methods and devices for processing low-frequency audio data are provided. A bass extraction process may involve applying low-pass filters to received audio object signals, to produce extracted low-frequency audio signals. The bass extraction process may be performed prior to a process of rendering audio objects into speaker feed signals. A bass management process may involve routing the extracted low-frequency audio signals to the one or more speakers capable of reproducing low-frequency audio signals.

A plasma power limiter fabricated using wafer-level fabrication techniques with other circuit elements. The power limiter includes a signal substrate having a first side and a second side, an input signal line formed on the first side, a signal transmission line formed on the second side and an output signal line formed on the first side. The power limiter also includes a ground substrate having a first side and a second side, and being bonded to the signal substrate to form a sealed cavity including an ionizable gas therebetween. The ground substrate includes a ground metal layer formed on the second side. A signal propagating on the input signal line at a power level greater than a threshold power level generates a voltage potential across the cavity that ionizes the gas and generates a plasma discharge, and limits power of the output signal coupled to the output signal line.

A clipping detector circuit includes a timer circuit and a counter circuit. The timer circuit is configured to monitor a time period elapsing since a last occurrence of an edge in a PWM signal, assert a first signal when the time period elapses, and de-assert the first signal and reset the time period as a result of an edge occurring in the PWM signal. The counter circuit is configured to determine a number of pulses in the PWM signal since the last de-assertion of the first signal, and assert a second signal when the number of pulses in the PWM signal since the last de-assertion of the first signal reaches m pulses. The clipping detector circuit is configured to generate a clipping detection signal indicative of whether the pulse-width modulated signal is clipped or not as a function of the first signal and the second signal.

A clipping detector circuit includes a timer circuit and a counter circuit. The timer circuit is configured to monitor a time period elapsing since a last occurrence of an edge in a PWM signal, assert a first signal when the time period elapses, and de-assert the first signal and reset the time period as a result of an edge occurring in the PWM signal. The counter circuit is configured to determine a number of pulses in the PWM signal since the last de-assertion of the first signal, and assert a second signal when the number of pulses in the PWM signal since the last de-assertion of the first signal reaches m pulses. The clipping detector circuit is configured to generate a clipping detection signal indicative of whether the pulse-width modulated signal is clipped or not as a function of the first signal and the second signal.

A voltage clamping circuit is provided. In an embodiment, the voltage clamping circuit includes a plurality of gain shifting circuits and a signal processing circuit. The plurality of gain shifting circuits receive an input voltage and voltage levels to generate a plurality of shifted voltages. The signal processing circuit generates a difference value of the plurality of shifted voltages to generate an output voltage according to the difference value, such that the voltage clamping circuit achieves an implementation of a passing band or a rejection of the input voltage.

Example embodiments provide a process that includes one or more of receiving an audio signal at a feedback compressor circuit, determining how much to attenuate the audio signal when a power level of the audio signal exceeds a threshold power level, combining the audio signal with an auxiliary attenuation signal from an auxiliary attenuation source and a compressed attenuation signal from the feedback compressor circuit to create a combination signal, and generating an audio output signal of the feedback compressor circuit based on the combination signal.