21. An apparatus comprising: a distortion computation module configured: to compare a first feature vector in a sequence of feature vectors formed from a digitized incoming signal to be recognized with a first number of templates from a set of templates representing candidate patterns, to select, based on said comparison, a second number of templates from said template set, the second number being smaller than the first number, to compare a second feature vector only with said selected templates so as to recognize a pattern of said digitized incoming signal; and to generate a signal corresponding to a recognized pattern of said digitized incoming signal as a result of said comparing said second feature vector only with said selected templates.
24. The apparatus according to claim 21 , wherein said distortion computation module configured to compare said second feature vector is configured to compare a number of successive feature vectors only with said selected templates.