An apparatus and method wherein speech or other signals are sampled during a time slice of approximately 1/30 second and spectrum analysis is performed on the samples, producing measures of amplitude in several frequency bands with each frequency band being characterized by a binary digit indicating the presence or absence of significant amplitude. The binary digits are collectively referred to as a sonogram. Sonograms for several time slices are then concatenated, randomized and decoded using an n-tuple technique to produce a pattern corresponding to the current speech signal. This pattern is learned by superimposing it on an existing vocabulary entry and is subsequently recognized if it is sufficiently similar to one vocabulary entry and different from all others.
SPEECH RECOGNITION APPARATUS