US 12,451,113 B2
Device and method for active noise control
James C. Ewing, Harrow (GB); James Griffin, Harrow (GB); and Donald Stewart Murray, Harrow (GB)
Assigned to INVISIO Communications Ltd, Watford (GB)
Filed by Invisio Communications Ltd, Watford (GB)
Filed on Jan. 27, 2023, as Appl. No. 18/160,528.
Claims priority of application No. 2201146 (GB), filed on Jan. 28, 2022.
Prior Publication US 2023/0245639 A1, Aug. 3, 2023
Int. Cl. G10K 11/178 (2006.01); H03F 3/183 (2006.01); H04R 1/10 (2006.01)
CPC G10K 11/17823 (2018.01) [G10K 11/17873 (2018.01); H04R 1/1041 (2013.01); H04R 1/1083 (2013.01); G10K 2210/1081 (2013.01); G10K 2210/12821 (2013.01); G10K 2210/3011 (2013.01); G10K 2210/3027 (2013.01); G10K 2210/3028 (2013.01); G10K 2210/3224 (2013.01); H03F 3/183 (2013.01); H03F 2200/03 (2013.01); H04R 2460/01 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An active noise reduction system arranged to be worn and/or carried by a user, the system comprising:
a headset arranged to provide passive noise reduction;
at least one noise detection microphone arranged to detect noise external to the headset;
at least one speaker for creating sound in the headset;
a battery; and
an active noise reduction circuit arranged to receive a signal from the at least one noise detection microphone and to apply active noise reduction to the signal to generate an active noise reduction output at the at least one speaker;
wherein:
the system is arranged to receive power both from an external power supply arranged external to the system and from the battery of the system;
the system is arranged to detect when the system is connected to the external power supply;
the system is arranged to automatically modify the applied active noise reduction in dependence on whether or not the system is connected to the external power supply; and
the system further comprises at least one audio amplifier associated with the headset for amplifying the active noise reduction signal received from the active noise reduction circuit, and further comprises means for switching the voltage supplied to the at least one amplifier in dependence on whether or not the system is connected to the external power supply, such that the at least one amplifier is powered from a higher voltage supply when the system is connected to the external power supply, and thus greater active noise reduction may be attained, than when the system is disconnected from the external power supply.