Harman Becker Automotive Systems Gmbh

Georg Spielbauer

Markus E Christoph

Leander Scholz

Florian Wolf

Peter Perzlmaier

Max Granger

Peter Perzimaier

A loudspeaker overload protection circuit and method receives at a compressor a signal representing the estimated loudspeaker power consumption; receives at the compressor a signal representing the nominal power of the loudspeaker; receives at the compressor an input audio signal from the signal source and supplying with the compressor an output audio signal to the loudspeaker; estimates from the output audio signal, (a) signal(s) that represent(s) the voltage and/or current supplied to the loudspeaker and a parameter that represents the ohmic resistance of the loudspeaker the power consumed by the loudspeaker; supplies a signal representing the estimated loudspeaker power consumption to the compressor; and attenuates the input audio signal when the signal representing the estimated loudspeaker power consumption exceeds the signal representing the nominal power of the loudspeaker.

Loudspeaker overload protection

A testing system tests an audio connection between an audio source and a loudspeaker. The system includes a loudspeaker that converts a reference signal into a sound. An adaptive filter processes the reference signal to minimize an error signal. A decision circuit analyzes the error signal and the received signal to determine signal correlation. When the signals are not correlated, a defect is detected.

Audio connection testing system

The invention relates to a compressor and method for amplifying an input signal with a controlled gain. An output signal representing the input signal is amplified by an initial gain and a signal level of the input signal or of the output signal is compared with a threshold level. If the signal level is below the threshold level, the initial gain value is updated using an adaptive control characteristic, and if the signal level is above the threshold level, the initial gain value is updated using a fixed control characteristic or an adaptive control characteristic respectively. The adaptive control characteristic is dependent on the signal level and the fixed control characteristic is independent from the signal level.

Feedback limiter with adaptive time control

An audio system includes a first transformation device provided with an input audio signal and which transforms the input audio signal from the time domain to the frequency domain resulting in an input spectrum. The system also includes a spectral processing device, which is connected downstream from the first transformation device, that receives the input spectrum and produces from it an output spectrum with a dynamic range that is reduced from that of the input spectrum. The system further includes a second transformation device connected downstream from the spectral processing device, and provided with the output spectrum. The second transformation device transforms the output spectrum from the frequency domain to the time domain, and provides an output audio signal.

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Haselbach, Germany

Georg Spielbauer