# US 2016/0253997 A1 · Low power detection of a voice control activation phrase > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0253997 A1 - Document ID: US20160253997A1 - Status: Published application - Kind: A1 - Application number: 14/663,583 - Filed: 2015-03-20 - Published: 2016-09-01 - Earliest claimed: 2015-02-27 - Assignees: Imagination Technologies Limited - Applicants: Imagination Technologies Limited - Inventors: Benjamin James KERR - Web page: https://patentgrep.com/patent/US20160253997A1 ## CPC - G10L 15/22: Procedures used during a speech recognition process, e.g. man-machine dialogue - G10L 15/28: Constructional details of speech recognition systems - G10L 2015/088: {Word spotting} - G10L 2015/223: {Execution procedure of a spoken command} - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract Methods of low power detection of an activation phrase are described. A microphone system comprises dedicated hardware logic for detecting a pre-defined activation phrase in an audio stream received via a microphone. If the pre-defined activation phrase is detected, the hardware logic sends a trigger signal to activate a module, such as a main speech detection module, which is external to the microphone system and which may be in a low power standby state. ## Claims ### Claim 1 A microphone system comprising a microphone and hardware logic configured to compare an audio stream received via the microphone with a pre-defined phrase and in response to detecting the pre-defined phrase in the audio stream, to send a trigger signal to activate a module external to the microphone system. ### Claim 2 (depends on 1) A microphone system according to claim 1, further comprising an audio buffer arranged to store a second portion of the audio stream received via the microphone after a first portion of the audio stream comprising the pre-defined phrase. ### Claim 3 (depends on 1) A microphone system according to claim 1, wherein the hardware logic is configured to divide a portion of detected audio into one or more component parts and to compare the component parts to one or more stored component parts of the pre-defined phrase. ### Claim 4 (depends on 1) A microphone system according to claim 1, further comprising an amplifier configured to amplify the audio stream received via the microphone according to a gain parameter and to output the amplified audio stream to the hardware logic which is configured to detect the pre-defined phrase, and wherein the hardware logic is further configured, in response to detecting the pre-defined phrase, to send a signal to the amplifier to increase a value of the gain parameter. ### Claim 5 (depends on 4) A microphone system according to claim 4, wherein the hardware logic is further configured to send a signal to the amplifier to reduce the value of the gain parameter in response to the module external to the microphone system entering a low power mode. ### Claim 6 (depends on 1) A microphone system according to claim 1, further comprising an analogue to digital converter configured to convert the audio stream received via the microphone into a digital audio stream by sampling the received audio stream at a sample rate and a sample resolution and to output the digital audio stream to the hardware logic which is configured to detect the pre-defined phrase and wherein the hardware logic is further configured, in response to detecting the pre-defined phrase, to send a signal to increase the sample rate and/or sample resolution. ### Claim 7 (depends on 6) A microphone system according to claim 6, wherein the hardware logic is further configured to send a signal to reduce the sample rate and/or sample resolution in response to the module external to the microphone system entering a low power mode. ### Claim 8 (depends on 1) A microphone system according to claim 1, further comprising an activation phrase store arranged to store the pre-defined phrase. ### Claim 9 (depends on 8) A microphone system according to claim 8, wherein the hardware logic is further configured, in response to detecting the pre-defined phrase, to update the stored pre-defined phrase using the detected pre-defined phrase. ### Claim 10 (depends on 1) A microphone system according to claim 1, wherein the hardware logic is further configured, in response to partially detecting the pre-defined phrase, to send a portion of the audio stream comprising the partially detected pre-defined phrase to the module external to the microphone system. ### Claim 11 (depends on 1) A microphone system according to claim 1, wherein the hardware logic is further configured, in response to partially detecting the pre-defined phrase in a first portion of the audio stream, to: determine if a previous portion of the audio stream comprising a partially detected pre-defined phrase was stored; in response to determining that the previous portion of the audio stream comprising a partially detected pre-defined phrase was not stored, to store the first portion of the audio stream; in response to determining that the previous portion of the audio stream comprising a partially detected pre-defined phrase was stored, to compare the first portion of the audio stream and he stored previous portion of the audio stream; and in response to detecting a match between the first portion of the audio stream and the stored previous portion of the audio stream, to send a trigger signal to activate the module external to the microphone system. ### Claim 12 (depends on 1) A microphone system according to claim 1, wherein the pre-defined phrase is a sample of a contextual sound. ### Claim 13 (depends on 1) A microphone system according to claim 1, wherein the pre-defined phrase comprises one or more spoken words. ### Claim 14 (depends on 13) A microphone system according to claim 13, wherein the pre-defined phrase is an activation phrase for a voice controlled computing device. ### Claim 15 (depends on 14) A microphone system according to claim 14, wherein the module external to the microphone system is a main speech detection module and the main speech detection module is implemented by a processor in the voice controlled computing device ### Claim 16 (depends on 13) A microphone system according to claim 13, wherein the microphone system comprises two modes of operation and wherein in a first mode of operation, the hardware logic is configured to detect a pre-defined phrase in an audio stream received via the microphone by dividing a portion of detected audio into one or more component parts and comparing the component parts to one or more stored component parts of the pre-defined phrase and in response to detecting the pre-defined phrase, to send a trigger signal to activate a first module external to the microphone system; and in a second mode of operation, the hardware logic is configured to divide a portion of detected audio into one or more component parts and to provide the component parts to a second module external to the microphone system. ### Claim 17 (depends on 16) A microphone system according to claim 16, wherein the first module external to the microphone system and the second module external to the microphone system are the same and the module is a main speech detection module. ### Claim 18 (depends on 16) A microphone system according to claim 16, wherein the first module external to the microphone system is a main speech detection module and the second module external to the microphone system is a communications interface arranged to transmit the component parts to a remote phrase detection and recognition system. ### Claim 19 (depends on 1) A microphone system according to claim 1, wherein the hardware logic is configured to continuously analyse the audio stream received via the microphone to detect the pre-defined phrase. ### Claim 20 A method of operating a microphone system comprising: detecting an audio stream from a microphone in the microphone system; comparing the detected audio stream with a pre-defined phrase stored in dedicated hardware in the microphone system,; and in response to detecting the pre-defined phrase in the detected audio stream, sending a trigger signal to activate a module external to the microphone system.