Cambridge Silicon Radio Limited

Qualcomm Technologies International, Ltd.

Peter Williams

Steven Singer

Hashem Zare-Hoseini

Harith Haboubi

Devices and methods of detecting a predetermined audio signal in audio signals are provided. A device includes a processor coupled to a clock signal generator, a power controller and an audio detector. The power controller controls a clock rate provided to the processor by the clock signal generator, to control the device to operate in a low power mode having a relatively low power consumption or in a normal power mode having a relatively high power consumption. The audio detector receives audio signals and detects, in the low power mode, probable presence of a predetermined audio signal in the audio signals. The power controller controls the device to switch from the low power mode to the normal power mode responsive to the detected presence of the predetermined audio signal by the audio detector.

Low power audio detection

The present invention relates to a multi-bit digital to analogue converter (DAC) and to a delta-sigma analogue to digital converter employing such a DAC. The DAC has a multi-bit input, a plurality of elements for processing an input signal received at the input and a selector for selecting, based on the input signal, one or more of the DAC elements to process the signal. The DAC has control means for controlling the selector such that if the input to the DAC is below a predetermined level for a predetermined period of time the selector is operative to select only a single one of the DAC elements to process the input signal. Also disclosed is a delta-sigma analogue to digital converter (ADC) employing such a DAC.

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Cambridge, United Kingdom

Peter Williams