Abstract: A voice activation system is described including a first voice activity detector for receiving a first signal from a microphone; a second voice activity detector for receiving a second signal from a speaker; a voice detector output coupled to the output of the first voice activity detector and the second voice activity detector. The first detector and the second detector are operable to generate an output signal in response to a candidate speech signal received on the respective detector inputs and the voice activation system is configured to generate a voice detector output signal when at least one of the first detector output and the second detector output indicate that speech has been detected. The voice activation system may reduce the average power consumption and increase the recognition rate of an always-on voice activation solution for headsets or other mobile audio devices.

Abstract: A circuit and method for determining an ambient temperature for an electronic device having a loudspeaker are described. An amplifier drives the loudspeaker and first circuitry is configure to determine an overall temperature of the loudspeaker or the amplifier. Second circuitry is configured to determine a change in temperature of the loudspeaker or the amplifier resulting from power dissipated in the loudspeaker or the amplifier. Third circuitry is configured to subtract a signal representative of the change in temperature from a signal representative of the overall temperature and output a signal representative of the ambient temperature for the electronic device.

Abstract: A voice activation system is described including a first voice activity detector for receiving a first signal from a microphone; a second voice activity detector for receiving a second signal from a speaker; a voice detector output coupled to the output of the first voice activity detector and the second voice activity detector. The first detector and the second detector are operable to generate an output signal in response to a candidate speech signal received on the respective detector inputs and the voice activation system is configured to generate a voice detector output signal when at least one of the first detector output and the second detector output indicate that speech has been detected. The voice activation system may reduce the average power consumption and increase the recognition rate of an always-on voice activation solution for headsets or other mobile audio devices.

Abstract: An acoustic coupling sensor 200 for a portable electronic device is described which includes an acoustic transmitter 22, a reference signal generator 20 coupled to the acoustic transmitter, and an acoustic sensor 24 wherein in operation, the reference signal generator is operable to transmit the reference signal to the acoustic transmitter, to detect an acoustic level of the transmitted reference signal via the acoustic sensor, and wherein the detected reference signal level corresponds to a value of acoustic coupling between the acoustic transmitter and the acoustic sensor. The acoustic coupling sensor may be used for example in a mobile phone to detect acoustic leakage in order to adapt the acoustic level in the mobile phone during use.

Abstract: Mobile devices such as mobile phones have always-on modes using sensors which respond to changes in the environment. A mobile device is described comprising a loudspeaker; a controller having an input coupled to the loudspeaker. The controller is operable in a first mode of operation to detect an electrical signal generated by the loudspeaker in response to an acoustic input signal. This signal can be used to activate further circuitry. Using a loudspeaker as an acoustic sensor may reduce the power consumption of the mobile device.

Abstract: A circuit and method for determining an ambient temperature for an electronic device having a loudspeaker are described. An amplifier drives the loudspeaker and first circuitry is configure to determine an overall temperature of the loudspeaker or the amplifier. Second circuitry is configured to determine a change in temperature of the loudspeaker or the amplifier resulting from power dissipated in the loudspeaker or the amplifier. Third circuitry is configured to subtract a signal representative of the change in temperature from a signal representative of the overall temperature and output a signal representative of the ambient temperature for the electronic device.

Abstract: A circuit embodied in a mobile device is disclosed. The circuit includes a headphone audio driver, a loudspeaker audio driver and a switch coupled to outputs of the headphone audio driver and the loudspeaker audio driver. The switch is configured to connect the output of the loudspeaker audio driver to an external speaker when an external speaker is connected to the mobile device. The external speaker may be detected using methods such as automatic accessory detection or impedance measurement or a user configuration or a use action. The circuit may also include an impedance detector to drive the switch based on an impedance measurement. A user interface is provided to enable a user of the mobile device to driver the switch based on user preferences.

Abstract: Mobile devices such as mobile phones have always-on modes using sensors which respond to changes in the environment. A mobile device is described comprising a loudspeaker; a controller having an input coupled to the loudspeaker. The controller is operable in a first mode of operation to detect an electrical signal generated by the loudspeaker in response to an acoustic input signal. This signal can be used to activate further circuitry. Using a loudspeaker as an acoustic sensor may reduce the power consumption of the mobile device.

Abstract: Accelerometers are used as motion sensors in mobile devices, such as mobile phones, to detect user inputs such as tapping. A motion sensor for a mobile device is described comprising a loudspeaker for outputting an audio signal, the loudspeaker having a loudspeaker input; a trigger detector having a trigger input coupled to the loudspeaker input, and a trigger output; wherein the trigger detector is operable to output a detection signal on the trigger output in response to a mechanically induced signal on the loudspeaker input due to a motion source. The power consumption of the motion sensor is reduced since the loudspeaker does not require any DC bias to detect a motion source such as a user tapping the motion sensor.

Abstract: A circuit embodied in a mobile device is disclosed. The circuit includes a headphone audio driver, a loudspeaker audio driver and a switch coupled to outputs of the headphone audio driver and the loudspeaker audio driver. The switch is configured to connect the output of the loudspeaker audio driver to an external speaker when an external speaker is connected to the mobile device. The external speaker may be detected using methods such as automatic accessory detection or impedance measurement or a user configuration or a use action. The circuit may also include an impedance detector to drive the switch based on an impedance measurement. A user interface is provided to enable a user of the mobile device to driver the switch based on user preferences.

Abstract: An acoustic coupling sensor 200 for a portable electronic device is described which includes an acoustic transmitter 22, a reference signal generator 20 coupled to the acoustic transmitter, and an acoustic sensor 24 wherein in operation, the reference signal generator is operable to transmit the reference signal to the acoustic transmitter, to detect an acoustic level of the transmitted reference signal via the acoustic sensor, and wherein the detected reference signal level corresponds to a value of acoustic coupling between the acoustic transmitter and the acoustic sensor. The acoustic coupling sensor may be used for example in a mobile phone to detect acoustic leakage in order to adapt the acoustic level in the mobile phone during use.

Abstract: A device for processing an audio signal is provided, wherein the processing device comprises a processing unit, and a determination unit, wherein the processing unit is adapted to receive first data associated with a first subsignal of the audio signal and second data associated with a second subsignal of the audio signal, and wherein the determination unit is adapted to determine a compensation value for one of the subsignals depending on a phase difference between the first subsignal and the second subsignal.

Abstract: The invention relates to an audio system and a method for the stereo enhancement of decoded stereo signals. When decoded stereo signals are stereo enhanced, artefacts can be unmasked and can thus become audible. The invention tries to achieve that a stereo enhancement for decoded stereo signals which is possible without restrictions and without artefacts from becoming audible. It is suggested that a frequency range of the stereo signal is defined in which artefacts might be unmasked due to the stereo enhancement. The boost which is applied to the first of a total of two mono signals of which the stereo signal is composed of (the first signal might be the S-signal in the mid/side representation) is determined by an artefact remover. This makes it possible to attenuate the first mono signal S within the above frequency range. As a net result, the first mono signal S is not boosted within this frequency range, such that artefacts are not unmasked.

Abstract: In a sound reproduction or recording system an audio signal is multiplied by a gain factor (z) which is dependent on the input level (y). The dependence of the gain factor on input level is chosen such that unvoiced phonemes are at least 6 dB, preferably at least 12 dB more enhanced than voiced phonemes, where preferably the average gain is less than 6 dB. This improves the intelligibility.