Systems and methods for automatic signal attenuation

摘要

The systems, devices, and methods provided herein can be used with an audio source to automatically attenuate a signal from the audio source in response to information about a local environment. In an example, an attenuation network circuit can be used to provide automatic or “hands-free” adjustment of a headphone or headset volume level to compensate for changing background sound or noise levels. In relatively noisy environments, the attenuation network can provide little or no attenuation of an audio source signal, and in less noisy environments, the attenuation network can provide greater attenuation of the audio source signal.

主权项

1. An apparatus, comprising:
an audio signal input; an audio signal output; an environment sensor configured to sense an environment parameter; an attenuation network coupled to the audio signal input and the audio signal output, the attenuation network configured to receive a source signal from the audio signal input and to provide an attenuated signal, based on the source signal, to the audio signal output; and a first processor circuit configured to update an attenuation magnitude characteristic of the attenuation network using information about the sensed environment parameter; wherein the attenuation network comprises:
a first resistive network comprising a plurality of series-connected resistive devices, each series-connected resistive device having an associated switching device that is configured to selectively shunt its associated series-connected resistive device in response to an instruction from the first processor circuit to change a resistance characteristic of the first resistive network; anda second resistive network comprising a plurality of parallel-connected resistive devices, each parallel-connected resistive device having an associated switching device that is configured to selectively decouple its associated parallel-connected resistive device in response to a different instruction from the first processor circuit to change a resistance characteristic of the second resistive network;wherein the first and second resistive networks are electrically coupled in series; andwherein one of the first and second resistive networks is coupled to the audio signal input, and the other one of the first and second resistive networks is coupled to the audio signal output.