Device and method for active noise control
AssigneeINVISIO Communications Ltd
InventorsJames C. Ewing, James Griffin, Donald Stewart Murray
Life of this patent
Estimating the term…
Abstract
The invention provides an active noise reduction system which may be self-contained within a headset of the system, wherein circuitry within the system applies an active noise reduction profile to a signal to the speakers in the headset, to provide active noise reduction to the user of the headset, the system being arranged to receive power both from a power supply external to the system and from a battery of the system and to automatically modify the active noise reduction applied, in dependence on whether or not the system is connected to an external power supply.
Claims14
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.
A method of active noise reduction for a headset having both an internal battery and a connection to an external power supply, the method comprising:
- detecting noise external to the headset;
- applying active noise reduction to an external noise signal within the headset to provide an active noise reduction output for a wearer of the headset;
- detecting when the headset is connected to the external power supply and automatically modifying the application of the active noise reduction in dependence on whether or not the system is connected to the external power supply;
- and
- supplying power to an amplifier for a speaker of the headset at a higher supply voltage, when it is detected that the headset is connected to the external power supply, and at a lower supply voltage, when it is detected that the headset is not connected to the external power supply.
Dependencies are inferred from the claim text.