Method and detector of loudspeaker diaphragm excursion
First Claim
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1. A method of detecting diaphragm excursion of an electrodynamic loudspeaker, comprising steps of:
- receiving a digital audio signal having a first sample rate,using an up-sampler and modulator circuit, up-sampling the digital audio signal to a greater second sample rate and adding a high-frequency probe signal to the up-sampled digital audio signal to generate a pulse-modulated composite drive signal, wherein the probe signal has a frequency that exceeds a Nyquist frequency of the received digital audio signal,applying the pulse-modulated composite drive signal to a voice coil of the electrodynamic speaker through an output amplifier,detecting a composite drive signal current flowing through the voice coil in response to the application of the pulse-modulated composite drive signal,detecting a modulation level of a probe signal current from the composite drive signal current, andidentifying an excursion of a diaphragm of the loudspeaker based on the detected modulation level of the probe signal current.
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Abstract
The present invention relates in one aspect to a method of detecting diaphragm excursion of an electrodynamic loudspeaker. The method comprises steps of generating an audio signal for application to a voice coil of the electrodynamic loudspeaker and adding a high-frequency probe signal to the audio signal to generate a composite drive signal. The method further comprises a step of applying the composite drive signal to the voice coil through an output amplifier and detecting a modulation level of a probe signal current flowing through the voice coil.
44 Citations
29 Claims
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1. A method of detecting diaphragm excursion of an electrodynamic loudspeaker, comprising steps of:
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receiving a digital audio signal having a first sample rate, using an up-sampler and modulator circuit, up-sampling the digital audio signal to a greater second sample rate and adding a high-frequency probe signal to the up-sampled digital audio signal to generate a pulse-modulated composite drive signal, wherein the probe signal has a frequency that exceeds a Nyquist frequency of the received digital audio signal, applying the pulse-modulated composite drive signal to a voice coil of the electrodynamic speaker through an output amplifier, detecting a composite drive signal current flowing through the voice coil in response to the application of the pulse-modulated composite drive signal, detecting a modulation level of a probe signal current from the composite drive signal current, and identifying an excursion of a diaphragm of the loudspeaker based on the detected modulation level of the probe signal current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A loudspeaker excursion detector for electrodynamic loudspeakers, comprising:
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an audio signal input for receipt of a digital audio signal supplied by an audio signal source, a probe signal source for generation of a high-frequency digital probe signal, an up-sampler and modulator circuit configured to up-sample the audio signal and then combine the up-sampled audio signal with the probe signal to provide a composite drive signal, an output amplifier configured to supply the composite drive signal at a pair of output terminals connectable to a voice coil of an electrodynamic loudspeaker, a current detector configured for detecting from the voice coil a composite drive signal current flowing through the voice coil in response to the application of the composite drive signal, and a modulation detector configured to determine a modulation level of a probe signal current of the composite drive signal current, wherein the modulation level indicates an excursion characteristic of a diaphragm of the electrodynamic loudspeaker. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification