# US 2014/0195228 A1 · Voice activity detection/silence suppression system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0195228 A1 - Document ID: US20140195228A1 - Status: Published application - Kind: A1 - Application number: 14/202,640 - Filed: 2014-03-10 - Published: 2014-07-10 - Earliest claimed: 2004-09-16 - Assignees: AT&T Intellectual Property II, L.P. - Applicants: AT&T Intellectual Property II, L.P. - Inventors: Bing Chen; James H. James - Web page: https://patentgrep.com/patent/US20140195228A1 ## CPC - G10L 25/93: Discriminating between voiced and unvoiced parts of speech signals (G10L25/90 takes precedence) - G10L 15/20: Speech recognition techniques specially adapted for robustness in adverse environments, e.g. in noise, of stress induced speech (G10L21/02 takes precedence) - G10L 19/012: Comfort noise or silence coding - G10L 25/21: the extracted parameters being power information - G10L 25/45: characterised by the type of analysis window - G10L 25/78: Detection of presence or absence of voice signals (switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10) - G10L 25/84: for discriminating voice from noise - G10L 2025/935: {Mixed voiced class; Transitions} - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract A Voice Activity Detection/Silence Suppression (VAD/SS) system is connected to a channel of a transmission pipe. The channel provides a pathway for the transmission of energy. A method for operating a VAD/SS system includes detecting the energy on the channel, and activating or suppressing activation of the VAD/SS system depending upon the nature of the energy detected on the channel. ## Claims ### Claim 1 A method of controlling a communication channel, the method comprising: determining, using a processing device, whether there is a decrease in communication energy associated with the communication channel; determining, using the processing device, whether noise energy associated with the communication channel is constant based on a spectrum constancy criterion; and activating silence suppression, using the processing device, in response to determining that the noise energy associated with the communication channel is constant based on the spectrum constancy criterion and determining that communication energy associated with the communication channel is decreased, the activating of silence suppression comprising associating communication energy with the communication channel that was not already associated with the communication channel prior to activating silence suppression. ### Claim 2 (depends on 1) The method according to claim 1, wherein determining whether the noise energy is constant based on the spectrum constancy criterion comprises analyzing fluctuation in a power frequency spectrum associated with the noise energy. ### Claim 3 (depends on 1) The method according to claim 1, wherein the communication energy comprises a text message. ### Claim 4 (depends on 2) The method according to claim 2, wherein analyzing fluctuation in the power frequency spectrum comprises determining whether the power frequency spectrum is constant, the method further comprising determining that the noise energy associated with the communication channel is constant based on the power frequency spectrum being constant. ### Claim 5 (depends on 1) The method according to claim 1, wherein activating silence suppression further comprises adding matching noise energy to the communication channel, the matching noise energy having a power frequency spectrum matching actual noise on the communication channel. ### Claim 6 (depends on 1) The method according to claim 1, further comprising determining whether there is a decrease in communication energy associated with the communication channel following activation of silence suppression. ### Claim 7 (depends on 1) The method according to claim 1, further comprising de-activating silence suppression in response to determining that the communication energy associated with the communication channel is present. ### Claim 8 A computer-readable storage device comprising instructions stored thereon that, when executed by a processing device, cause the processing device to perform operations comprising: determining whether there is a decrease in communication energy associated with a communication channel; determining whether noise energy associated with the communication channel is constant based on a spectrum constancy criterion; and activating silence suppression in response to determining that the noise energy associated with the communication channel is constant based on the spectrum constancy criterion and determining that the communication energy associated with the communication channel is decreased, the activating of silence suppression comprising associating communication energy with the communication channel that was not already associated with the communication channel prior to activating silence suppression. ### Claim 9 (depends on 8) The computer-readable storage device according to claim 8, further comprising instructions stored thereon that, when executed by the processing device, cause the processing device to perform operations comprising analyzing fluctuation in a power frequency spectrum associated with the noise energy to determine whether the noise energy is constant. ### Claim 10 (depends on 8) The computer-readable storage device according to claim 8, wherein the communication energy comprises a text message. ### Claim 11 (depends on 9) The computer-readable storage device according to claim 9, further comprising instructions stored thereon that, when executed by the processing device, cause the processing device to perform operations comprising: determining whether the power frequency spectrum is constant; and determining that the noise energy associated with the communication channel is constant based on the power frequency spectrum being constant. ### Claim 12 (depends on 8) The computer-readable storage device according to claim 8, further comprising instructions stored thereon that, when executed by the processing device, cause the processing device to perform operations comprising adding matching noise energy to the communication channel, the matching noise energy having a power frequency spectrum matching actual noise on the communication channel. ### Claim 13 (depends on 8) The computer-readable storage device according to claim 8, further comprising instructions stored thereon that, when executed by the processing device, cause the processing device to perform operations comprising determining whether there is a decrease in communication energy associated with the communication channel following activation of silence suppression. ### Claim 14 (depends on 8) The computer-readable storage device according to claim 8, further comprising instructions stored thereon that, when executed by the processing device, cause the processing device to perform operations comprising de-activating silence suppression in response to determining that the communication energy associated with the communication channel is present. ### Claim 15 An apparatus to control a communication channel, the apparatus comprising: a processing device; and a computer-readable storage device storing instructions that, when executed by the processing device, cause the processing device to perform operations comprising: determining whether there is a decrease in communication energy associated with the communication channel; determining whether noise energy associated with the communication channel is constant based on a spectrum constancy criterion; and activating silence suppression in response to determining that the noise energy associated with the communication channel is constant based on the spectrum constancy criterion and that the communication energy associated with the communication channel is decreased, the activating of silence suppression comprising associating communication energy with the communication channel that was not already associated with the communication channel prior to activating silence suppression. ### Claim 16 (depends on 15) The apparatus according to claim 15, wherein the instructions, when executed by the processing device, further cause the processing device to perform operations comprising analyzing fluctuation in a power frequency spectrum associated with the noise energy to determine whether the noise energy is constant. ### Claim 17 (depends on 16) The apparatus according to claim 16, wherein the instructions, when executed by the processing device, further cause the processing device to perform operations comprising analyzing fluctuation in the power frequency spectrum for a duration of 100 msec. ### Claim 18 (depends on 16) The apparatus according to claim 16, wherein the instructions, when executed by the processing device, further cause the processing device to perform operations comprising: determining whether the power frequency spectrum is constant; and determining that the noise energy associated with the communication channel is constant based on the power frequency spectrum being constant. ### Claim 19 (depends on 15) The apparatus according to claim 15, wherein the instructions, when executed by the processing device, further cause the processing device to perform operations comprising disabling silence suppression in response to determining that the communication energy associated with the communication channel is present. ### Claim 20 (depends on 15) The apparatus according to claim 15, wherein the instructions, when executed by the processing device, further cause the processing device to perform operations comprising determining whether there is a decrease communication energy associated with the communication channel following activation of silence suppression.