Adaptive Band-Pass Filter Tracking for Voice Formant Detection
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Solution Overview
Problem
Existing sound wave signal processing systems struggle to efficiently detect formant frequencies in voice signals, leading to increased power consumption and cost due to the use of numerous band pass filters and inefficient detection methods.
Innovation Solution
A sound wave signal processing apparatus utilizing two band pass filters (BPFs) that dynamically adjust their center frequencies based on output level comparisons, allowing for precise detection of formant frequencies with reduced components and power consumption by detecting formant frequency bands between cross point frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple band pass filters are used to detect formant frequency bands, then detection accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent implements dynamic adjustment of the band pass filter's center frequency based on temporal changes in output levels. The center frequency is automatically updated when the output level ratio between adjacent frequency bands exceeds a threshold, allowing the system to track formant frequency bands over time with a single filter rather than requiring multiple fixed filters for each possible formant position
Solution Approach 2:
A single band pass filter is designed to perform multiple detection functions by dynamically changing its center frequency. The same filter component detects different formant frequency bands at different time points, replacing the need for multiple dedicated filters for each formant position, thus achieving multi-functionality with reduced component count
2Measurement precision
If multiple band pass filters are used to detect formant frequency bands, then detection accuracy is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts the band pass filter's center frequency based on temporal changes in output levels. The center frequency is automatically updated when the output level ratio between adjacent frequency bands exceeds a threshold, allowing the system to track formant frequency bands over time with a single filter rather than requiring multiple fixed filters for each possible formant position
Solution Approach 2:
A single band pass filter is designed to perform multiple detection functions by dynamically changing its center frequency. The same filter component detects different formant frequency bands at different time points, replacing the need for multiple dedicated filters for each formant position, thus achieving multi-functionality with reduced component count
3Device complexity
If the number of band pass filters is reduced, then device complexity and power consumption decrease, but detection accuracy deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of the band pass filter's center frequency based on temporal changes in output levels. The center frequency is automatically updated when the output level ratio between adjacent frequency bands exceeds a threshold, allowing the system to track formant frequency bands over time with a single filter rather than requiring multiple fixed filters for each possible formant position
Solution Approach 2:
The system uses feedback from the output level comparison to automatically adjust the center frequency of the band pass filter. When the output level ratio between adjacent frequency bands exceeds a threshold, the center frequency is updated to track the formant frequency band, creating a closed-loop control system that maintains detection accuracy with minimal components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively detects formant frequencies with reduced power consumption and cost by using two BPFs that adapt their frequencies, enabling rapid detection of formant frequency bands at intervals as short as 5 ms, reducing the number of components and power requirements.
Implementation Method 1
a first band pass filter (first BPF) extracts, from a voice signal, a first frequency signal indicating a frequency component in a first frequency band including a first set frequency
Data Source
AI summary
A sound wave signal processing apparatus may include: an extraction unit configured to extract, from a sound wave signal, a plurality of frequency signals indicating respective frequency components of a plurality of frequency bands including different set frequencies; a setting unit configured to set a set frequency of the extraction unit on the basis of a comparison result between output levels of the frequency signals of the different set frequencies extracted by the extraction unit; and a detection unit configured to detect a formant frequency band including a formant frequency in the sound wave signal on the basis of a comparison result group between the output levels of the frequency signals of the different set frequencies extracted by the extraction unit, a setting history of the set frequency of the extraction unit by the setting unit, and a frequency characteristic of the extraction unit.