SPEECH PRESENCE MEASUREMENT DETECTION TECHNIQUES

In order to enhance the quality of a communication signal derived from speech and noise, the likelihood that the communication signals result from at least some speech is determined. A calculator calculates a first power signal representing the power of at least a portion of the communication signals estimated over a first time period and calculates a second power signal representing the power of at least a portion of the communication signals estimated over a second time period longer than the first time period. The calculator also generates a comparison signal having a value related to the likelihood that the portion of the communication signals result from at least some speech by comparing a first expression involving the first power signal with a second expression involving the second power signal. The calculator also generates a speech likelihood signal having a value representing a first likelihood that the communication signal results from at least some speech in the event that the comparison signal value falls within a first range and having a second value representing a second likelihood that the communication signal results from at least some speech in the event that the comparison signal value falls within a second range. The second likelihood is different from the first likelihood.