How to use the Voice Activity Detection in the TAx511x and TAx521x
Abstract
The TAx511x and TAx521x devices are a family of high performance stereo codecs suitable for Land Mobile Radio, IP Network and Telephone, Video Conferencing, and Professional Audio Equipment. This family of devices has an extensive set of features that include the following:
- Real-Time DSP-based digital mixer
- Digital volume control
- Programmable filters (Biquads, HPF)
- Automatic gain control (AGC)/ Dynamic range compression (DRC)
- Linear-phase or Low-latency filter modes
- Ultrasound activity Detection/generator
- Voice activity detection (VAD)
This application note describes how to configure the Voice Activity Detection (VAD) feature in TAx511x and TAx521x devices (TAA5111, TAA5112, TAC5111, TAC5112, TAA5211, TAA5212, TAC5211, TAC5212).
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1 Introduction
The Voice Activity Detection (VAD) algorithm is a voice-triggered, system wake-up mechanism. The VAD feature enables the device or system (depending on the application) to be in sleep mode: consuming minimal power in the absence of voice activity. The TAx5x1x can generate an interrupt upon the detection of voice activity.Figure 1-1 shows how the VAD responds to voice activity.
Figure 1-1 VAD ExampleThe VAD feature is supported on all analog-to-digital converter (ADC) channels of the TAx511x and TAx521x device family, including digital microphone channels, with one channel being monitored at a time. The digital microphone channel is preferred for low-power applications. TI recommends that the audio sampling rate of the device be 8kHz for best performance, however 48kHz is supported if higher fidelity is needed. This application note describes the operation of the VAD, the tunable parameters, and the device configurations required to support VAD.
