Cirrus Logic Inc.

Actiwave Ab

Other

Cirrus Logic International Semiconductor Limited

Erik Vilhelm Lindahl

Pär Gunnars Risberg

Ylva Ellen Maria Bjork

Landy Aaron Toth

Marcus Arvidsson

Daniel Stahre

Gunnar Hovsenius

Jason William Lawrence

Christopher Ekbom

Methods and Apparatus for estimating a temperature of an electromechanical transducer. The method comprising receiving an audio signal (); providing an output signal to the electromechanical transducer, based on the audio signal (); and determining whether a first magnitude of the audio signal in a first frequency band is above a magnitude threshold (). In response to the first magnitude being above or equal to the magnitude threshold, calculating a first impedance of the electromechanical transducer based on measurements of a first voltage and a first current of the electromechanical transducer within the first frequency band (), and estimating the temperature of the electromechanical transducer based on the first impedance (). In response to the first magnitude being below the magnitude threshold, inserting a pilot tone into the audio signal (), wherein the pilot tone is at a pilot tone frequency, calculating a second impedance of the electromechanical transducer based on measurements of a second voltage and a second current of the electromechanical transducer at the pilot tone frequency (), and estimating the temperature of the electromechanical transducer based on the second impedance ().

Temperature monitoring for loudspeakers

A nonlinear control system and a loudspeaker protection system. In particular, a nonlinear control system including a controller, an audio system, and a model is disclosed. The controller is configured to accept one or more input signals, and one or more estimated states produced by the model to produce one or more control signals. The audio system includes one or more transducers configured to accept the control signals to produce a rendered audio stream therefrom. An active loudspeaker with an integrated amplifier is disclosed. A loudspeaker protection system and a quality control system are disclosed. More particularly, a system for clamping the input to a loudspeaker dependent upon a bank of representative models is disclosed.

Control and protection of loudspeakers

A method for characterizing a loudspeaker comprises: filtering an input test signal by applying the inverse of a linear model describing an excursion of the loudspeaker in response to a given input signal, the linear model containing only linear terms; applying the filtered input test signal to the loudspeaker; measuring the excursion of the loudspeaker in response to the filtered input test signal; and, based on the measured excursion, determining one or more non-linear parameters for a non-linear model describing the excursion of the loudspeaker in response to a given input signal.

Linear and non-linear speaker excursion modeling

Embodiments of the invention provide methods and apparatus for processing audio input signals, for example, so as to linearize the output of a given loudspeaker. An audio processor is provided, for modifying an audio signal to be provided to a loudspeaker, the audio processor comprising: a first filter stage, for applying to an audio signal a linear model describing an excursion of the loudspeaker in response to a given input signal, the linear model containing only linear terms, and for generating one or more excursion signals; a plurality of second filters for receiving the one or more excursion signals, each of the second filters configured to apply to a respective one of a plurality of frequency bands in the one or more excursion signals the inverse of a model describing an excursion of the loudspeaker in response to a given input signal; and a combiner for combining the outputs of each of the plurality of second filters. At least a first one of the plurality of second filters applies the inverse of a non-linear model describing an excursion of the loudspeaker in response to a given input signal, the non-linear model comprising one or more non-linear parameters.

Audio processor with linear and non-linear modeling including limiter

An asynchronous sample rate converter and method for converting an input signal to a resampled output signal is disclosed. An efficient and cost-effective sample rate converter for converting an input signal of arbitrary sample rate to a resampled output signal of a second sample rate is disclosed. A hardware-efficient sample-rate converter for resampling an audio input signal with an arbitrary sample rate to an output audio signal with a known sample rate for use in an audio processor is disclosed.

Asynchronous sample rate converter

A signal conversion system and method for converting an input signal to a pulse width modulated signal is disclosed. The signal conversion system includes a sample rate converter coupled with an associated pulse width modulation (PWM) module. A hardware and power efficient signal conversion system for resampling an audio input signal with an arbitrary sample rate to a pulse width modulated output audio signal for use in an audio processor and/or reproduction is disclosed. The signal conversion system may be particularly suitable for use in a battery operated consumer electronics device.

Signal conversion system and method

Method for cleansing metal-containing solutions

A method of flue-gas cleaning comprising the separation of water-soluble substances from flue gases containing water vapor. The invention is characterized in that the flue gases are caused to be cooled by direct contact between flue gas and atomized water in two or more separation steps, where in a separation step (2) subsequent in the flow direction of the flue gases the flue gases are cooled by atomized water to a temperature, at which the water in the flue gases is condensed out, which water is collected and thereafter both recirculated for utilization in said subsequent separation step (2) and introduced into a separation step (1) prior in the flow direction of the flue gases. In said prior separation step the water is atomized and meets uncleaned flue gases, the water-soluble and potentially water-soluble substances of which thereby are solved in the atomized water. The water thus impurified is collected for further treatment.

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Stockholm, Sweden

Erik Vilhelm Lindahl