Wireless Headset Spectral Parameter Transmission for Speech Recognition
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Solution Overview
Problem
Current Bluetooth standards are inadequate for speech recognition applications due to limitations in data link reliability, dynamic range, and quantization error, which result in increased speech recognition errors and reduced performance.
Innovation Solution
A wireless device that uses correlation processing to represent spectral characteristics of audio signals as data packets, transmitted via a Bluetooth transceiver using an asynchronous connection-less link, rather than traditional voice packets, to improve link reliability and reduce quantization error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional Bluetooth SCO link with 8-bit voice packets is used, then link bandwidth is minimized and power consumption is reduced, but data link reliability deteriorates and quantization error increases
Solution Approach 1:
The patent changes the data representation format from traditional 8-bit voice samples to linear 16-bit spectral parameters. This parameter change increases the data width from 8 bits to 16 bits, providing higher dynamic range and reduced quantization error while maintaining acceptable bandwidth through efficient spectral encoding that captures speech essentials with fewer parameters.
2Quantity of substance
If traditional Bluetooth SCO link with 8-bit voice packets is used, then link bandwidth is minimized, but quantization error increases
Solution Approach 1:
The patent transitions from 8-bit non-linear encoding to 16-bit linear spectral parameter representation. This parameter change directly reduces quantization error by increasing the precision from 8 bits to 16 bits, while the spectral encoding methodology ensures that the increased precision is used efficiently to represent speech characteristics with reduced overall data quantity.
3Device complexity
If traditional Bluetooth SCO link is used, then device complexity is minimized, but speech recognition performance deteriorates
Solution Approach 1:
The patent replaces the traditional voice packet transmission mechanism with a spectral parameter transmission approach. Instead of transmitting raw or compressed voice samples, the system extracts and transmits spectral characteristics (formants, pitch, energy) that are then synthesized at the receiver. This substitution provides higher quality speech data for recognition while the spectral parameters are compact enough to maintain efficient Bluetooth communication.
4Manufacturing precision
If higher sample rate and bit depth are used, then speech quality is improved, but link bandwidth requirement increases
Solution Approach 1:
The patent extracts the essential spectral characteristics from the full speech signal rather than transmitting the complete high-resolution audio stream. By identifying and transmitting only the critical spectral parameters (formant frequencies, bandwidths, pitch contours, energy levels), the system achieves high speech quality for recognition purposes while dramatically reducing the data bandwidth requirement compared to transmitting full-rate audio.
Data Source
AI summary
A wireless device for use with speech recognition applications comprises a frame generator for generating successive frames from digitized original audio signals, the frames representing portions of the digitized audio signals. An autocorrelation circuit generates a set of coefficients for each frame, the coefficient set being reflective of spectral characteristics of the audio signal portion represented by the frame. In one embodiment, the autocorrelation coefficients may be used to predict the original audio signal to be subtracted from the original audio signals and to generate residual signals A Bluetooth transceiver is configured for transmitting the set of coefficients and/or residual signals as data to another device, which utilizes the coefficients for speech applications.