Loudspeaker Excursion Prediction With Down-Sampled Impulse Response
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Solution Overview
Problem
Existing loudspeaker excursion prediction circuits face a trade-off between calculation and storage requirements and precision, with higher-order impulse responses providing better accuracy but increasing computational and storage burdens, while lower-order responses result in significant prediction errors.
Innovation Solution
A loudspeaker excursion prediction system incorporating a low-pass filter circuit, down-sampling circuit, and impulse response generation unit, which reduces the order of the impulse response filter while maintaining high accuracy by adjusting the sampling frequency and using a 128-order filter for frequencies up to 6 kHz, thereby reducing memory storage and DSP operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a higher-order impulse response filter is used, then prediction accuracy is improved, but calculation and storage requirements increase
Solution Approach 1:
The patent segments the impulse response filter into multiple smaller filters with lower orders. Instead of using a single high-order filter (e.g., 1024-order), the system divides it into several low-order filters (e.g., multiple 128-order filters), each handling different frequency bands or time segments. This segmentation maintains overall prediction accuracy while significantly reducing the computational and storage burden of each individual filter.
Solution Approach 2:
The patent transitions from a single high-order filter in one dimension to multiple low-order filters operating in additional dimensions (frequency bands, time segments, or parallel processing channels). By adding these dimensional divisions, the system achieves the same prediction accuracy through distributed processing, reducing the complexity of any single filter component.
2Device complexity
If the order of impulse response is reduced, then calculation and storage requirements decrease, but prediction accuracy deteriorates significantly
Solution Approach 1:
The patent merges multiple low-order impulse response filters to achieve the cumulative effect of a single high-order filter. Each low-order filter processes a specific portion of the signal (different frequency ranges or time periods), and their outputs are combined through addition or other composite operations. This merging strategy preserves the overall prediction accuracy that would otherwise require a single high-order filter, while distributing the computational load across multiple simpler components.
Data Source
AI summary
A loudspeaker excursion prediction system, which is suitable for a loudspeaker protection circuit comprises a low-pass filter circuit, a down-sampling circuit, and an impulse response generation unit. The low-pass filter circuit is configured to generate an audio signal XLPF(t) passing through the low-pass filter circuit according to an audio signal X(t) with a first sampling frequency. A down-sampling circuit, coupled to the low-pass filter circuit, is configured to down-sampling the first sampling frequency of the audio signal XLPF(t) output from the low-pass filter circuit to a second sampling frequency, so as to generate a down-sampled audio signal XLPFDN(t). The impulse response generation unit, coupled to the down-sampling circuit, is configured to generate an excursion prediction value according to a loudspeaker excursion transfer function and the down-sampled audio signal XLPFDN(t).