Patent ID: 7236929

Claim:
At least one computer readable medium having computer program instructions stored therein for detecting speech in a telephony system, the computer program instructions comprising: first instructions for measuring an energy level associated with a received signal; second instructions for comparing the energy level with a current noise estimate; third instructions for updating the current noise estimate to be equal to the energy level where the energy level is less than the current noise estimate; fourth instructions for increasing the current noise estimate using an upward bias where the energy level is greater than the current noise estimate; fifth instructions for setting a hysteresis value with reference to whether speech is determined to be occurring, comprising setting the hysteresis value to a nonzero constant if speech is currently determined to be occurring and setting the hysteresis value to zero if speech is currently determined not to be occurring; and sixth instructions for detecting speech energy with reference to a threshold and the hysteresis value, the threshold being determined with reference to the current noise estimate.