METHOD OF DETERMINING SPEECH SPECTRA WITH AN APPLICATION TO AUTOMATIC SPEECH RECOGNITION AND SPEECH CODING

摘要

1. A method of determining speech spectra for automatic speech recognition and speech coding, wherein a codebook tree is used, namely an arrangement of codebook spectra which is orientated with binary branching and thus can be addressed in binary-coded fashion, with levels which contain 2**L spectra, characterized in that in an analysis stage (A) which is supplied with a speech signal which is to be analysed, firstly, preferably using a signal processor (S), the respective spectral parameter set is determined, that each obtained parameter set comprising parameter values Pi is binary-coded in a coding stage (C) whereby each parameter value Pi is assigned a code Ci , that all the codes ({Ci }) which have been formed and which are to be evaluated are combined to form an overall code (Cg ), that the overall code (Cg ) is used as addressing signal for a read-only store ROM, namely a Hash-ROM (H), where the store content of the Hash-ROM (H) comprises the numbers, assigned to the required spectrum, of the codebook spectra in a K-th level of the codebook tree, that the numbers of the codebook spectra are used as an indicator of the codebook store section which contains the codebook tree from the K-th level, and that when entering into the K-th level of the codebook tree has been facilitated in this way, a final determination of the codebook spectrum in the L-th level of the codebook tree is carried out by means of a comparator unit (V) in the form of a tree search.