Analog voice activity detection
According to some embodiments, an analog processing portion may receive an audio signal from a microphone. The analog processing portion may then convert the audio signal into sub-band signals and estimate an energy statistic value, such as a Signal-to-Noise Ratio (“SNR”) value, for each sub-band signal. A classification element may classify the estimated energy statistic values with analog processing such that a wakeup signal is generated when voice activity is detected. The wakeup signal may be associated with, for example, a battery-powered, always-listening audio application.
1. A voice activity detection device, comprising:
an analog processing portion to receive an audio signal from a microphone, convert the audio signal into sub-band signals, and estimate an energy statistic value for each sub-band signal, including:
for each sub-band signal, a bandpass filter and one or more asymmetric integrators to output an energy value and a noise value for that sub-band signal; and
a classification element to classify the estimated energy statistic values with analog processing such that a wakeup signal is generated when voice activity is detected.
2. The device of claim 1 , wherein the estimated energy statistic value is a Signal-to-Noise Ratio (“SNR”) value.
3. The device of claim 1 , wherein the analog processing portion and classification element are integrated into the microphone.
4. The device of claim 1 , wherein the energy values and noise values are associated with feature extraction.
5. The device of claim 4 , wherein the feature extraction is further associated with transient noise features.
6. The device of claim 4 , wherein extracted features are output when the wakeup signal is generated.
7. The device of claim 4 , wherein extracted features are provided to a feature combination element.
8. The device of claim 7 , wherein the extracted features are provided to the feature combination element via a programmable switch matrix.
9. The device of claim 7 , wherein the feature combination element provides data to a decision integration element that generates the wakeup signal.