Transducer displacement protection
AssigneeBang & Olufsen Icepower A/S
InventorsMads Emil Solgaard, Bjorn Sand Jensen
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Abstract
This invention relates to the mechanical protection using digital processing and a predictive estimation of instantaneous displacement of the voice coil in a loudspeaker transducer. The invention solves the problem of limiting the coil displacement of the transducer by applying a look-a-head based linear or non-linear predictor and a controller operating directly on the displacement signal in order to finally convert back into the incoming signal domain.
Claims13
A method for controlling and limiting voice coil displacement of an electro dynamic transducer, the method comprising:
- a. predicting an instantaneous displacement signal based on a digital audio input signal, intended to be amplified and supplied to the transducer,
- b. delaying the predicted displacement signal a predefined number of samples,
- c. controlling the delayed, predicted displacement signal,
- d. applying an inverse filter structure to transform the predicted displacement into a signal domain of the digital audio input signal.
A loadspeaker system comprising:
- an amplifier arranged to amplify a digital audio input signal,
- a transducer arranged to receive an amplified signal from the amplifier,
- a predictor for predicting an instantaneous displacement signal based on the digital audio input signal,
- a delay element for delaying the predicted displacement signal a predefined number of samples,
- a controller for controlling the delayed, predicted displacement signal, so as to limit voice coil displacement of the electro dynamic transducer,
- an inverse filter structure to transform the predicted displacement into a signal domain of the digital audio input signal.
Dependencies are inferred from the claim text.