Dominant Frequency Processing for Audio Signal Harmonics
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Solution Overview
Problem
Small speakers in computing devices struggle to produce low frequency tones, leading to a loss of low frequency components in audio signals, and existing methods to compensate for this often result in intermodulation distortion and phase-related issues that degrade audio clarity.
Innovation Solution
A system and method that selects a dominant frequency in an audio signal, generates harmonics of that frequency, and inserts them into the audio output to create the perception of low frequency components, while using filters and alignment engines to minimize distortion and phase differences across audio channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If small speakers are used in computing devices to reduce size and weight, then portability and device compactness are improved, but low frequency audio output capability deteriorates
Solution Approach 1:
The patent uses harmonics as an intermediary to bridge the gap between small speaker capabilities and perceived low frequency output. By generating harmonic frequencies (integer multiples) of the desired low frequency and inserting them into the audio signal, the system creates the perception of low frequency content without requiring the physical speaker to reproduce those frequencies directly
Solution Approach 2:
The system changes the frequency parameter of the audio signal by generating harmonics at integer multiples of the dominant frequency. This transforms the spectral content of the audio signal, creating perceived low frequency content through higher frequency harmonics that small speakers can actually reproduce
2Reliability
If non-linear processing is applied to generate harmonics, then perception of low frequency components is improved, but intermodulation distortion increases
Solution Approach 1:
The patent extracts only the necessary harmonic components (integer multiples of the dominant frequency) from the non-linear processing output, rather than passing all generated frequencies through to the output. This selective extraction removes harmful intermodulation distortion products while retaining the beneficial harmonic content that creates low frequency perception
Solution Approach 2:
The system uses non-linear processing to generate harmonics, then deliberately filters out the harmful intermodulation distortion products. The harmful distortion is converted into a benefit by using the filtering process to isolate and retain only the clean harmonic frequencies that contribute to low frequency perception
3Device complexity
If audio channels are combined without alignment, then processing complexity is reduced, but phase-related cancellations occur
Solution Approach 1:
The patent performs time alignment of audio channels as a preliminary action before combining them. By adjusting the timing of each channel to compensate for propagation delays and processing differences, the system prevents phase-related cancellations from occurring in the first place, ensuring coherent summation of the harmonics across all channels
Data Source
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AI summary
An example non-transitory computer-readable medium includes instructions. When executed by a processor, the instructions cause the processor to remove nondominant frequencies from a low frequency portion of an audio signal. The instructions also cause the processor to apply non-linear processing to a remainder of the low frequency portion to generate a plurality of harmonics. The instructions cause the processor to insert the plurality of harmonics into an audio output corresponding to a high frequency portion of the audio signal. The audio output is to be provided to an audio output device.