A low power Voice Activity Detector for portable applications

Voice Activity Detectors (VADs) are used to enhance performances and to reduce the activation rate of speech recognition and key-word spotting applications. The last aspect is crucial for portable applications because it allows to save energy, increasing battery life. During last decades, VADs have been realized through hardware solutions to increase their speed in processing and to reduce their power consumption. However, the hardware implementation often represents a limit on the choice of the features to use, limiting the performances on recognition. This paper shows a low-power and low-area serial logistic regression classffier which uses the frame-energy, the maximum absolute signal finite difference and the maximum absolute squared signal finite difference over a frame as features. The system has been implemented on IGLOO nano Field Programmable Gate Array (FPGA), leading to power consumption of 0.559 mW and offering acceptable performances for its use as a preprocessor for speech recognition systems or a more sophisticated software VAD.