Abstract: This system verifies the voice of a specific speaker (A) through verification of vocal sounds which form a previously-recorded recognition phrase spoken by A and others. Parallel filters derive a spectral characteristic parameter x.sub.i which contains weighting factors .alpha..sub.i, .beta..sub.i, and which represents a corresponding vocal sound x.sub.i. Improved specificity over other speakers is attained by a Characteristic Feature Extractor which varies .alpha..sub.i, .beta..sub.i, through p different values, thus deriving a set of p parameters (x.sub.ik) for each vocal sound x.sub.i, thus allowing emphasis of the specific vocal sound x.sub.i as spoken by a specific speaker, over that of competing sounds and speakers.

Abstract: In a voice verification system, voice parameters which are highly characteristic of particular voices but have only a limited effectiveness life time (such as pitch) are used. The lifetime or similar time indication is recorded along with the original record of the characteristic parameter. At the time of verification, if the lifetime has been exceeded no verification is made. On the other hand if the lifetime of the recorded characteristic parameter has not been exceeded a verification is made. If the verification is positive the newly obtained characteristic parameter is substituted for the originally recorded parameter and the lifetime begins anew.