Vibration sensor and acoustic voice activity detection systems (VADS) for use with electronic systems
A voice activity detector (VAD) combines the use of an acoustic VAD and a vibration sensor VAD as appropriate to the conditions a host device is operated. The VAD includes a first detector receiving a first signal and a second detector receiving a second signal. The VAD includes a first VAD component coupled to the first and second detectors. The first VAD component determines that the first signal corresponds to voiced speech when energy resulting from at least one operation on the first signal exceeds a first threshold. The VAD includes a second VAD component coupled to the second detector. The second VAD component determines that the second signal corresponds to voiced speech when a ratio of a second parameter corresponding to the second signal and a first parameter corresponding to the first signal exceeds a second threshold.
1. A method comprising:
receiving, at a processing component, a first signal from a first detector and a second signal from a second detector, wherein the first signal is different from the second signal;
applying, at a first processing path of the processing component, a first delay to the first signal and a first gain to the first signal;
applying, at a second processing path of the processing component, a second delay to the first signal and a second gain to the first signal;
applying, at a third processing path of the processing component, a third delay to the second signal and a third gain to the second signal;
applying, at a fourth processing path of the processing component, a fourth delay to the second signal and a fourth gain to the second signal;
summing, at the processing component, an output of the first processing path with an output of the third processing path to form a first virtual microphone; and
summing, at the processing component, an output of the second processing path with an output of the fourth processing path to form a second virtual microphone.
2. The method of claim 1 , wherein the first detector comprises a first omnidirectional microphone.
3. The method of claim 1 , wherein the second detector comprises a second omnidirectional microphone.
4. The method of claim 1 , wherein the first and second detectors comprise a dual omnidirectional microphone array.
5. The method of claim 1 and further comprising:
varying, at the processing component, a magnitude of the first delay, the third delay or both to configure the first virtual microphone as a first variable virtual microphone.
6. The method of claim 1 and further comprising:
varying, at the processing component, a magnitude of the second delay, the fourth delay or both to configure the second virtual microphone as a second variable virtual microphone.
7. The method of claim 1 and further comprising:
varying, at the processing component, a sign of the first delay, the third delay or both to configure the first virtual microphone as a first variable virtual microphone.
8. The method of claim 1 and further comprising:
varying, at the processing component, a sign of the second delay, the fourth delay or both to configure the second virtual microphone as a second variable virtual microphone.
9. The method of claim 1 and further comprising:
varying, at the processing component, a magnitude and a sign of the first delay, the third delay or both to configure the first virtual microphone as a first variable virtual microphone.
10. The method of claim 1 and further comprising:
varying, at the processing component, a magnitude and a sign of the second delay, the fourth delay or both to configure the second virtual microphone as a second variable virtual microphone.
11. The method of claim 1 and further comprising:
generating, at the processing component, a voice activity detection signal to indicate a presence of voiced speech when the first signal corresponds to voiced speech and a skin contact state of the first detector is a first state; and
generating the voice activity detection signal when either of the first signal and die second signal correspond to voiced speech and the skin contact state of the first detector is a second state.