Patent ID: 8442817

Claim:
A voice activity decision apparatus comprising: a processor in communication with a memory, wherein the processor is configured to receive an input signal; an autocorrelation calculation module stored in the memory and executable with the processor, the autocorrelation calculation module configured to calculate a plurality of autocorrelation values for the input signal, the plurality of autocorrelation values calculated within a predetermined interval; a delay calculation module stored in the memory and executable with the processor, the delay calculation module configured to receive the autocorrelation values calculated within the predetermined interval by the autocorrelation calculation module, and further configured to identify local maximum valued autocorrelation values within the autocorrelation values, and the delay calculation module further configured to calculate a plurality of delays within the predetermined interval, wherein the delays comprise a respective delay for each of the local maximum valued autocorrelation values; a noise decision module stored in the memory and executable with the processor, the noise decision module configured to receive the delays, the noise decision module further configured to determine whether variations between the received delays are less than a threshold for at least a predetermined period of time, and further configured to generate a signal characteristic determination that the input signal includes a non-noise portion based upon determination that the variations between the received delays are less than the threshold for the at least the predetermined period of time; an activity detector module stored in the memory and executable with the processor, the activity detector module configured to receive the signal characteristic determination of the input signal, and further configured to determine a signal activity decision based on the signal characteristic determination; and a noise estimation module stored in the memory and executable with the processor, the noise estimation module configured to receive the input signal and generate a noise estimate for the input signal, wherein the activity detector module is further configured to determine the signal activity decision based on the signal characteristic determination, the input signal, and the noise estimate, and the noise estimation module is further configured to adapt the noise estimate based on the signal activity decision.