Soft Clipping Audio Signal Processing Using Threshold-Based Suppression
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Solution Overview
Problem
Conventional soft-clipping techniques in audio signal processing suppress input signals regardless of their peak amplitude, leading to harmonic distortion and loss of power in the output signal, as they apply a non-linear function uniformly, whereas dynamic soft-clipping is needed to minimize distortion while maximizing output power.
Innovation Solution
A method is introduced where the suppression of audio samples is determined based on their peak amplitude, applying a strictly increasing non-linear function only when the amplitude exceeds a threshold, with a suppression factor calculated to minimize distortion and maintain signal power, using a Sigmoid function or error function for smoothing within the threshold range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a non-linear function is applied uniformly to suppress audio samples, then harmonic distortion is reduced, but output power is lost
Solution Approach 1:
The patent applies different processing to different parts of the audio signal based on their amplitude characteristics. Samples with peak amplitude exceeding the threshold range undergo soft-clipping suppression, while samples within the threshold range are passed through unchanged. This localized application of the non-linear function reduces harmonic distortion only where necessary, preserving output power in the majority of samples.
Solution Approach 2:
The suppression mechanism dynamically adjusts its behavior based on the instantaneous peak amplitude of each audio sample. The system transitions from no suppression (when amplitude is within threshold) to gradual suppression (when amplitude exceeds threshold), creating a dynamic response that optimizes both distortion reduction and power preservation in real-time.
2Manufacturing precision
If a non-linear function is applied to suppress audio samples, then signal amplitude is reduced to within threshold range, but signal integrity is degraded
Solution Approach 1:
The system determines the peak amplitude of each audio sample before applying suppression, allowing it to pre-calculate the appropriate suppression factor. This preliminary assessment enables the non-linear function to be applied in a controlled manner that maintains signal integrity while achieving precise amplitude control within the threshold range.
Solution Approach 2:
The patent transforms the binary decision of whether to suppress a sample into a continuous parameter adjustment by introducing a suppression factor that varies with the degree of threshold exceedance. This parameter change allows for gradual amplitude control that preserves signal integrity while maintaining precise amplitude control.
3Manufacturing precision
If suppression is applied to all audio samples, then amplitude is controlled within threshold range, but distortion increases in samples that did not need suppression
Solution Approach 1:
The patent implements amplitude control only where needed by comparing each sample's peak amplitude against the threshold range. Samples within the threshold range bypass suppression entirely, avoiding unnecessary distortion, while only samples exceeding the threshold undergo controlled suppression. This local application of amplitude control eliminates wasteful distortion in unaffected samples.
Data Source
AI summary
A method of processing an audio signal comprising a plurality of audio samples, the method comprising: receiving an audio sample of the plurality of audio samples; on determining that a peak amplitude of the audio sample falls outside a threshold range: suppressing the audio sample to within the threshold range by applying a strictly increasing non-linear function to the audio sample; and outputting the suppressed audio sample; and on determining that the peak amplitude of the audio sample falls within the threshold range or is equal to an upper or lower limit of the threshold range: outputting the received audio sample.