# US 2021/0241748 A1 · Systems and methods for transitioning a noise-cancellation system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241748 A1 - Document ID: US20210241748A1 - Status: Published application - Kind: A1 - Application number: 16/782,676 - Filed: 2020-02-05 - Published: 2021-08-05 - Earliest claimed: 2020-02-05 - Assignees: Bose Corporation - Applicants: Bose Corporation - Inventors: Cristian M. Hera; Elie Bou Daher; Siamak Farahbakhsh - Web page: https://patentgrep.com/patent/US20210241748A1 ## CPC - G10K 11/17883: {the reference signal being derived from a machine operating condition, e.g. engine RPM or vehicle speed} - G10K 11/17823: {Reference signals, e.g. ambient acoustic environment} - G10K 11/17825: {Error signals} - G10K 11/17854: {the filter being an adaptive filter} - G10K 11/17879: {using both a reference signal and an error signal} - G10K 2210/1282: Automobiles - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR ## Abstract A vehicle-implemented noise-cancellation system, includes: a noise-cancellation system disposed in a vehicle, the noise-cancellation system comprising an adaptive filter being adjusted according to a reference signal and an error signal, the adaptive filter outputting a noise-cancellation signal, which, when transduced into a noise-cancellation audio signal by a speaker, cancels road noise within at least one zone within a cabin of the vehicle; and an adjustment module configured to vary a power of the noise-cancellation signal or a rate of adaptation of the adaptive filter from a first value to a second value, passing through at least one intermediate value between the first value and the second value, based on a time-varying signal indicative of a signal-to-noise ratio of the reference signal with respect to a first criterion. ## Claims ### Claim 1 A vehicle-implemented noise-cancellation system, comprising: a noise-cancellation system disposed in a vehicle, the noise-cancellation system comprising an adaptive filter being adjusted according to a reference signal and an error signal, the adaptive filter outputting a noise-cancellation signal, which, when transduced into a noise-cancellation audio signal by a speaker, cancels road noise within at least one zone within a cabin of the vehicle; and an adjustment module configured to vary a power of the noise-cancellation signal or a rate of adaptation of the adaptive filter from a first value to a second value, passing through at least one intermediate value between the first value and the second value, based on a comparison of a time-varying signal indicative of a signal-to-noise ratio of the reference signal to a first criterion. ### Claim 2 (depends on 1) The vehicle-implemented noise-cancellation system of claim 1, wherein the time-varying signal is at least one of: a speed of the vehicle, a power of the reference signal, revolutions per minute of an engine of the vehicle, gear position of an engine of the vehicle, and a measure of similarity between the outputs of at least two of the reference sensor signals. ### Claim 3 (depends on 1) The vehicle-implemented noise-cancellation system of claim 1, wherein the first criterion is at least one fixed threshold. ### Claim 4 (depends on 1) The vehicle-implemented noise-cancellation system of claim 1, wherein the first criterion is at least one variable threshold, the variation of the at least one variable threshold being based upon a second time-varying signal indicative of the signal-to-noise ratio of the reference signal. ### Claim 5 (depends on 1) The vehicle-implemented noise-cancellation system of claim 1, wherein the intermediate value is determined according to a predetermined function of the time-varying signal. ### Claim 6 (depends on 5) The vehicle-implemented noise-cancellation system of claim 5, wherein the predetermined function is a linear function. ### Claim 7 (depends on 5) The vehicle-implemented noise-cancellation system of claim 5, wherein the predetermined function is a logarithmic function. ### Claim 8 A vehicle-implemented noise-cancellation system, comprising: a noise-cancellation system disposed in a vehicle, the noise-cancellation system comprising an adaptive filter being adjusted according to a reference signal and an error signal, the adaptive filter outputting a noise-cancellation signal, which, when transduced into a noise-cancellation audio signal by a speaker, cancels road noise within at least one zone within a cabin of the vehicle; and an adjustment module configured to vary a power of the noise-cancellation signal or a rate of adaptation of the adaptive filter from a first value to a second value based on a comparison of a of a time-varying input indicative of a state of the vehicle or a measure of relationship between two or more reference sensors to a first criterion. ### Claim 9 (depends on 8) The vehicle-implemented noise-cancellation system of claim 8, wherein the state of the vehicle is at least one of: a speed of the vehicle, revolutions per minute of an engine of the vehicle, and gear position of an engine of the vehicle. ### Claim 10 (depends on 8) The vehicle-implemented noise-cancellation system of claim 8, wherein the first criterion is at least one fixed threshold. ### Claim 11 (depends on 8) The vehicle-implemented noise-cancellation system of claim 8, wherein the first criterion is at least one variable threshold, the variation of the variable threshold being based upon a second time-varying signal indicative of the signal-to-noise ratio of the reference signal. ### Claim 12 A computer-implemented method for smoothly transitioning a vehicle-implemented noise-cancellation system from an off state to an on state, comprising: receiving a input indicative of a signal-to-noise ratio of a reference sensor of the noise-cancellation system; comparing a value of the signal to a first threshold, wherein if a value of the signal is less than the first threshold a power of a noise-cancellation signal or a rate of adaptation of the noise-cancellation system is set to a first value, wherein if the value of the signal is greater than the first threshold, performing the step of: comparing the value of the signal to a second threshold, wherein if the value of the signal is greater than the second threshold, the power of the noise-cancellation or the rate of adaptation is set to a second value, wherein if the signal is greater than the first threshold and less than the second threshold the power of a noise-cancellation signal or the rate of adaptation is set to an intermediate value, wherein the second threshold is greater than the first threshold. ### Claim 13 (depends on 12) The computer-implemented method of claim 12, wherein the input is at least one of: a speed of the vehicle, a power of the reference signal, revolutions per minute of an engine of the vehicle, gear position of an engine of the vehicle, and a measure of similarity between the outputs of at least two reference sensors. ### Claim 14 (depends on 12) The computer-implemented method of claim 12, wherein the value of the intermediate value is determined according to a predetermined function of the input. ### Claim 15 (depends on 14) The computer-implemented method of claim 14, wherein the predetermined function is a linear function. ### Claim 16 (depends on 14) The computer-implemented method of claim 14, wherein the predetermined function is a logarithmic function. ### Claim 17 (depends on 12) The computer-implemented method of claim 12, wherein the value of the first threshold and the second threshold are determined according to a second signal indicative of a signal-noise-ratio of the reference sensor. ### Claim 18 (depends on 12) The computer-implemented method of claim 12, further comprising the steps of: receiving a second input indicative of a signal-to-noise ratio of the reference sensor; comparing a value of the second signal to a third threshold, wherein if a value of the signal is less than the third threshold the first threshold is set to a first threshold value, wherein if the value of the second signal is greater than the third threshold, performing the step of: comparing the value of the second signal to a fourth threshold, wherein if the value of the second signal is greater than the fourth threshold the first threshold is set to a second threshold value, wherein if the second signal is greater than the third threshold and less than the fourth threshold the first threshold is set to an intermediate value, wherein the second threshold is greater than the first threshold.