Microphone Unit With Integrated Speech Coder For Low Power Transmission

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Solution Overview

Problem

Existing digital microphone systems face high power consumption due to inefficient data bit rate on interfaces, particularly in Always-On Voice modes, which limits battery life in portable devices while requiring sufficient information for speech recognition and keyword detection.

Innovation Solution

Incorporating a microphone unit with on-chip or co-packaged integrated speech coder circuitry that transmits compressed speech data at a low bit rate, using speech coding techniques such as MDCT, CELP, or MFCC to reduce power consumption during data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital microphone data is transmitted at high bit rate to maintain speech recognition accuracy, then downstream processing performance is improved, but power consumption increases significantly

Engineering Contradiction:
Improvespeech recognition accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential features from the audio signal using feature extraction circuitry (such as MFCC coefficients) rather than transmitting the complete audio waveform. This selective extraction of meaningful information reduces the data volume to be transmitted while preserving speech recognition accuracy, directly resolving the contradiction between transmission quality and power consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the representation parameters of audio data from raw waveform samples to compressed feature parameters (e.g., MFCC coefficients). This parameter transformation significantly reduces the bit rate required for transmission while maintaining the information content needed for accurate speech recognition, thereby reducing power consumption without sacrificing accuracy.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If data bit rate is reduced to save power, then power consumption is minimized, but sufficient information for speech recognition is lost

Engineering Contradiction:
Improvepower consumptionVSAvoidspeech information content
Core Design Contradiction:
Use of energy by moving objectVSLoss of information

Solution Approach 1:

The patent extracts only the essential features from the audio signal using feature extraction circuitry (such as MFCC coefficients) rather than transmitting the complete audio waveform. This selective extraction of meaningful information reduces the data volume to be transmitted while preserving speech recognition accuracy, directly resolving the contradiction between transmission quality and power consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary feature extraction and compression stage between the microphone and the transmission interface. This intermediary processing layer converts the raw audio signal into a compact representation that retains essential speech information, acting as a mediator that enables low-bit-rate transmission without information loss for recognition purposes.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If microphone remains permanently enabled for voice commands, then voice functionality is always available, but battery life is significantly reduced

Engineering Contradiction:
Improvevoice command availabilityVSAvoidbattery life
Core Design Contradiction:
Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent performs preliminary feature extraction and compression of audio data at the microphone level before transmission to the main processing unit. This preliminary action reduces the data volume that needs to be transmitted and processed, enabling the microphone to remain permanently enabled for voice commands while significantly reducing the overall power consumption and extending battery life.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the essential features from the audio signal using feature extraction circuitry (such as MFCC coefficients) rather than transmitting the complete audio waveform. This selective extraction of meaningful information reduces the data volume to be transmitted while preserving speech recognition accuracy, directly resolving the contradiction between transmission quality and power consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS10297258B2Microphone unit comprising integrated speech analysis
Publication Date: 2019.05.21 CIRRUS LOGIC INC
  • US10297258B2 patent drawing
  • US10297258B2 patent drawing
  • US10297258B2 patent drawing

AI summary

A microphone unit has a transducer, for generating an electrical audio signal from a received acoustic signal; a speech coder, for obtaining compressed speech data from the audio signal; and a digital output, for supplying digital signals representing said compressed speech data. The speech coder may be a lossy speech coder, and may contain a bank of filters with center frequencies that are non-uniformly spaced, for example mel frequencies.