The present invention provides methods and systems for narrow bandwidth digital processing of an input audio signal. Particularly, the present invention includes a high pass filter configured to filter the input audio signal. A first compressor then modulates the filtered signal in order to create a partially processed signal. In some embodiments, a clipping module further limits the gain of the partially processed signal. A splitter is configured to split the partially processed signal into a first signal and a second signal. A low pass filter is configured to filter the first signal. A pass through module is configured to adjust the gain of the second signal. A mixer then combines the filtered first signal and the gain-adjusted second signal in order to output a combined signal. In some embodiments, a tone control module further processes the combined signal, and a second compressor further modulates the processed signal.

The present invention provides methods and systems for narrow bandwidth digital processing of an input audio signal. Particularly, the present invention includes a high pass filter configured to filter the input audio signal. A first compressor then modulates the filtered signal in order to create a partially processed signal. In some embodiments, a clipping module further limits the gain of the partially processed signal. A splitter is configured to split the partially processed signal into a first signal and a second signal. A low pass filter is configured to filter the first signal. A pass through module is configured to adjust the gain of the second signal. A mixer then combines the filtered first signal and the gain-adjusted second signal in order to output a combined signal. In some embodiments, a tone control module further processes the combined signal, and a second compressor further modulates the processed signal.

An improved automatic loudness control system and method comprise controlling gain/attenuation applied to an input audio signal and providing an output audio signal that is the amplified/attenuated input audio signal; evaluating an actual loudness of the input audio signal from the input audio signal and a desired loudness of the input audio signal from a volume control input; and evaluating the gain/attenuation applied to the input audio signal from the actual loudness and the desired loudness of the input audio signal.

An apparatus includes an input terminal to receive a radio frequency (RF) signal and to communicate the RF signal to a low noise amplifier (LNA) via an input signal path, and a capacitor attenuator coupled to the input terminal to attenuate the RF signal by a controllable amount and having a first portion controllable to include a used part configured on the input signal path and an unused part coupled between the input signal path and an AC reference node, and a second portion coupled between the LNA and the AC reference node.

A radio frequency receiver and an automatic gain control method of the radio frequency receiver is presented. The radio frequency receiver includes an automatic gain control apparatus, a radio frequency component, and an analog to digital converter, where the automatic gain control apparatus further includes: an intensity calculator configured to calculate a relationship between an intensity representation parameter of digital data and a preset intensity threshold within a preset calculation time; and an automatic gain controller configured to compare the relationship calculated by the intensity calculator with a preset relationship threshold, and adjust a gain of the radio frequency component on radio frequency data according to a comparison result, so that an amplitude of the radio frequency data obtained after the gain adjustment is within a receiving range of the analog to digital converter.

An audio amplifier and a warning sound amplifier are connected in parallel to each other, relative to a voice coil of a loudspeaker. A resistor having an impedance greater than an impedance of the voice coil is connected to the voice coil and is also connected to the warning sound amplifier. An audio signal from the warning sound amplifier is input to the voice coil via the resistor. Thus, since the warning sound amplifier is connected to the resistor having the impedance greater than the impedance of the voice coil of the loudspeaker, even in a case where only the audio amplifier is operated, a large current is prevented from flowing into the warning sound amplifier.

The present invention is directed to electrical circuits. In a specific embodiment, the present invention provides variable gain amplifier that includes an impedance ladder and a control circuit. The impedance ladder includes n switches configured in parallel. The control circuit includes a digital-to-analog converter and an amplifier. The control circuit generates n control signals for the n switches. There are other embodiments as well.

An apparatus and a method for improving nonlinearity of a power amplifier in a wireless communication system are provided. A transmission apparatus in a wireless communication system comprises: at least one processor; a transceiver; and an amplifier for amplifying a signal provided from the transceiver, wherein if a power of a signal inputted into the transceiver is smaller than a reference value, the transceiver attenuates the power of the signal based on a gain compensation value corresponding to the power of the signal.

A method of and a system for generating an acoustic wave representing reverberations from a desired acoustic environment are described including having a recording surface (11) defined by a spatial distribution of recording transducers (o) and an emitting surface defined by a spatial distribution of emitting transducers (x), wherein the emitting surface (12) defines a volume within which the recording surface (11) is located, recording an acoustic wave (14) originating from within a volume defined by the recording surface (11) using the recording transducers (x), extrapolating the recorded wave (14) to the emitting surface using wavefield propagator system (IS) representing the desired acoustic environment, and emitting the extrapolated wave from the emitting transducers (o).

Example techniques may provide volume enhancements to a media playback system. An example implementation involves a first playback device in a first playback configuration playing audio at a first volume level and storing the first volume level in association with the first playback configuration. The first playback device receives instructions to change to a second playback configuration. Based on receiving the instructions, the first playback device joins a synchrony group with a second zone and adjusts the first playback device to play audio at a second volume level which is based on a volume level of a second playback device in the second zone. While in the second playback configuration, the first playback device receives instructions to change to the first playback configuration and, based on the instructions, leaves the synchrony group and adjusts the first playback device to play audio content at the stored first volume level.