Microphone circuit assembly and system with speech recognition

a microphone circuit and microphone technology, applied in the field of microphone circuit assembly and system with speech recognition, can solve the problems of high power consumption in high computational complexity of the mfcc filter bank, and the obstacle to providing voice activated system power up, etc., to achieve high internal gain factor, reduce power consumption, and high efficiency

Inactive Publication Date: 2017-07-06
ANALOG DEVICES INT UNLTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is about a microphone circuit assembly with speech recognition capabilities. This assembly acts as a pre-filter for a running speech recognition application on an external application processor. This reduces the computational load and power consumption of the external processor by discarding the processing of large amounts of incoming microphone signal samples. The microphone circuit assembly also includes a floating point converter that converts microphone signal samples from a binary fixed point format into a proprietary or standardized binary floating point format to reduce its power consumption. This results in a markedly smaller number of bits for representing high dynamic range internal signals with a reduced computational load and power consumption.

Problems solved by technology

However, MFCC filter banks of known speech recognition devices and systems are computationally complex and for this reason often executed on a programmable application processor such as a programmable fixed or floating point DSP core or engine.
This feature leads to high power consumption in the MFCC filter bank during processing of the incoming speech or audio signal which is a significant problem or obstacle for the application of MFCC based speech recognition in portable / battery powered equipment.
This requirement for continuous operation of the programmable external application processor presents an obstacle for providing voice activated system power up due to high power consumption of the continuously operating programmable application processor.
The high power consumption is a significant problem for the speech recognition application in both battery powered portable equipment and mains connected electrical equipment in view of battery life-time and the on-going world-wide efforts to reduce energy consumption of electrical equipment throughout the industrialized world.

Method used

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  • Microphone circuit assembly and system with speech recognition
  • Microphone circuit assembly and system with speech recognition
  • Microphone circuit assembly and system with speech recognition

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first embodiment

[0045]FIG. 2 is a schematic drawing of above-mentioned the microphone circuit assembly 201 in accordance with the present invention. The microphone circuit assembly 201 comprises a mixture of analog and digital signal processing blocks or sub-circuits and digital memory. The skilled person will therefore understand that the microphone circuit assembly 201 may be implemented on two or more separate semiconductor dies or chips for example a first semiconductor die comprising mainly analog circuitry and a second semiconductor die comprising mainly digital logic circuitry including digital memory elements. However, in the present embodiment, the microphone circuit assembly 201 is implemented on a single mixed-signal semiconductor die 203 fabricated in suitable semiconductor processes such as 0.35 μm, 0.18 μm or 0.065 μm CMOS or BiCMOS. The single mixed-signal semiconductor the 203 is preferably shaped and sized to be accommodated inside a housing of a miniature ECM or integrated with a ...

second embodiment

[0046]The microphone circuit assembly 201 comprises a signal conditioner 204 coupled to a speech recognition unit 206. The signal conditioner 204 comprises a microphone preamplifier 210 coupled to an externally accessible input terminal IN, for receipt of a microphone signal supplied by a microphone 205. The microphone 205 may comprise a miniature ECM or a miniature MEMS condenser microphone for mobile terminals such as mobile phones, smartphones etc. The microphone preamplifier 210 has preferably extremely large input impedance at audio frequencies to allow direct connection to a condenser transducer element of the miniature ECM or a miniature MEMS condenser microphone. This input impedance may be larger than 1 GΩ. The microphone 205 generates the microphone signal in response to impinging sound, in particular human speech. The signal conditioner 204 further comprises en analog-to-digital converter 212 configured for receipt of an output signal of the microphone preamplifier 210. T...

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Abstract

The present invention relates in one aspect to a microphone circuit assembly for an external application processor such as a programmable Digital Signal Processor. The microphone circuit assembly comprises a microphone preamplifier and analog-to-digital converter generate microphone signal samples at a first predetermined rate. A speech feature extractor is configured for receipt and processing of predetermined blocks of the microphone signal samples to extract speech feature vectors representing speech features of the microphone signal samples. The microphone circuit assembly additionally comprises a speech vocabulary comprising a target word or target phrase of human speech encoded as a set of target feature vectors and a decision circuit is configured to compare the speech feature vectors generated by the speech feature extractor with target feature vectors to detect the target speech word or phrase. A controller is configured to generate a recognition signal on an externally accessible output terminal of the microphone circuit assembly in response to a recognized target word or phrase in the microphone signal samples. Additional aspects of the invention relates to Digital Signal Processing Systems comprising the microphone circuit assembly.

Description

[0001]The present invention relates in one aspect to a microphone circuit assembly for connection to an external application processor such as a programmable Digital Signal Processor. The microphone circuit assembly comprises a microphone preamplifier and analog-to-digital converter to generate microphone signal samples at a first predetermined sample rate. A speech feature extractor is configured for receipt and processing of predetermined blocks of the microphone signal samples to extract speech feature vectors representing speech features of the microphone signal samples. The microphone circuit assembly additionally comprises a speech vocabulary comprising a target word or target phrase of human speech encoded as a set of target feature vectors and a decision circuit is configured to compare the speech feature vectors generated by the speech feature extractor with the target feature vectors to detect the target speech word or phrase. A controller is configured to generate a recog...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G10L15/28G10L15/10G10L15/02
CPCG10L15/28G10L15/22G10L15/10G10L15/02H04R3/00H04R2225/43G10L15/063G10L15/08G10L15/26
Inventor MORTENSEN, MIKAEL
Owner ANALOG DEVICES INT UNLTD
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