Abstract: An audio signal attenuation system and method for detecting an audio emergency warning signal (or alarm) in a vehicle in which an audio signal is being played. Embodiments of the system and method make it easier for a police, fire, or other emergency alarm or siren to be heard in a loud or noisy listening environment when audio signal is being reproduced. This is achieved using selective frequency attenuation, which identifies a frequency of the alarm and then selectively attenuates the alarm frequency in the audio signal. Moreover, direction data that includes information about from which direction the alarm is coming can be used to selectively attenuate the alarm frequency in certain channels (or speakers) of the audio signal. In some embodiments, audio cues are used to alert the listener to the alarm signal and are adjusted based on alarm distance from the vehicle, speed, and the type of alarm.

Abstract: An apparatus includes a first squelch circuit and a second squelch circuit. The first squelch circuit is configured to detect possible squelch signals in a communication signal. The second squelch circuit is configured to selectively detect the possible squelch signals in the same communication signal. The second squelch circuit is further configured to operate in a low-power state responsive to the first squelch circuit detecting none of the possible squelch signals in the communication signal. The second squelch circuit is further configured to operate in a high-power state responsive to the first squelch circuit detecting one of the possible squelch signals in the communication signal.

Abstract: An audio signal attenuation system and method for detecting an audio emergency warning signal (or alarm) in a vehicle in which an audio signal is being played. Embodiments of the system and method make it easier for a police, fire, or other emergency alarm or siren to be heard in a loud or noisy listening environment when audio signal is being reproduced. This is achieved using selective frequency attenuation, which identifies a frequency of the alarm and then selectively attenuates the alarm frequency in the audio signal. Moreover, direction data that includes information about from which direction the alarm is coming can be used to selectively attenuate the alarm frequency in certain channels (or speakers) of the audio signal. In some embodiments, audio cues are used to alert the listener to the alarm signal and are adjusted based on alarm distance from the vehicle, speed, and the type of alarm.

Abstract: Apparatus having corresponding methods comprise: a first squelch circuit configured to detect possible squelch signals in a communication signal; and a second squelch circuit configured to i) operate in a low-power state responsive to the first squelch circuit detecting none of the possible squelch signals in the communication signal, and ii) operate in a high-power state responsive to the first squelch circuit detecting one of the possible squelch signals in the communication signal.