Analog Audio Feature Extraction Without ADC Power Overhead

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Solution Overview

Problem

Existing digital systems for natural language processing in audio applications face high power consumption issues, which is problematic for battery-powered devices, and require significant power for analog-to-digital conversion and buffering.

Innovation Solution

An all-analog natural language processing system that performs audio activity detection, voice activity detection, feature extraction, and neural network processing directly in the analog domain using a bandpass filter bank with programmable current conveyor sections and a neural network configured for audio/voice feature classification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital systems are used for natural language processing, then processing accuracy is maintained, but power consumption increases significantly

Engineering Contradiction:

Improveprocessing accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces the digital signal processing system with an optical signal processing system. Specifically, it uses optical filters (including Fourier transform optics and Gabor filters) to perform feature extraction and neural network processing in the optical domain, eliminating the need for analog-to-digital conversion and digital processing, thereby significantly reducing power consumption while maintaining processing accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the domain parameter from electrical/digital to optical. By implementing the entire signal processing chain (filtering, feature extraction, neural network processing) in the optical domain using light-based components, the system achieves low power consumption characteristic of optical systems while preserving the computational accuracy needed for natural language processing

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If analog-to-digital conversion is performed, then digital processing capability is enabled, but power consumption and system complexity increase

Engineering Contradiction:

Improvedigital processing capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent eliminates the analog-to-digital conversion stage by substituting electrical/digital processing with optical processing. The system directly processes analog audio signals through optical filters and neural network components in the optical domain, removing the power-hungry ADC and associated digital processing infrastructure while maintaining full processing capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the analog-to-digital conversion function from the system architecture. By implementing feature extraction and neural network processing directly in the optical domain, the system eliminates the need for ADC, buffer memory, and digital processing units, significantly reducing power consumption and system complexity

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If audio buffering is implemented, then signal replay capability is provided, but power consumption and processing overhead increase

Engineering Contradiction:

Improvesignal replay capabilityVSAvoidpower consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent replaces digital buffer memory with optical delay line implementations. The buffering function is achieved through optical means (such as optical delay elements or feedback loops in the optical neural network), eliminating the need for digital-to-analog conversion cycles and reducing the power consumption associated with digital buffer management

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 all-analog system achieves natural language processing with comparable accuracy to digital systems but with energy consumption reduced by up to two orders of magnitude, making it suitable for power-constrained applications.

Implementation Method 1

Each bandpass filter includes an array of individual capacitively coupled current conveyor second order sections

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

charge-trapped transistor as a programmable element for tuning the passband of the filter

Methodology Applied

Scientific EffectCharge trapping:

Data Source

PatentUS20250166616A1Analog systems and methods for audio feature extraction and natural language processing

Publication Date: 2025.05.22 BLUMIND INC

AI summary

An all-analog natural language processing system is provided. Analog audio input is processed directly by an all-analog signal pathway wherein the audio activity detection, voice activity detection, feature extraction and neural network processing are all performed in the analog domain. Audio/voice detection and feature extraction is performed by a bandpass filter bank having a plurality of individual bandpass filters. Each bandpass filter includes an array of individual capacitively coupled current conveyor second order sections having a charge-trap transistor as a programmable element for tuning the passband of the filter. Compared to typical digital systems for natural language processing, the present all-analog system can perform natural language processing with comparable accuracy but greatly reduced energy consumption of up to two orders of magnitude less.