Cselt-centro Studi E Laboratori Telecomunicazioni S.p.a.

Presidenza Dei Consiglio Dei Ministri Del Ministro Per Il Coordinamento

Alberto Ciaramella

Luigi Licciardi

Riccardo Cecinati

Giovanni Venuti

Robert Tasso

Maurizio Paolini

Michele Cavazza

This connected-speech recognition system uses a two-level hierarchical system, in which the higher-level (master) processor and one or more lower-level units (slaves) process, respectively, the most probably word sequence within a permitted grammar network, and the likelihood of individual words with the grammar network. The lower-level processing performs dynamic programming involving vector and matrix calculation and comparison, and processing speed is improved by an integrated processing unit which has simultaneous access to the external data memory as well as to a high-speed internal microinstruction ROM. One of the aforementioned units can also provide for performing an additional internal test function. The structure features two internal data buses and internal memories for more commonly used data and addresses, for enabling high-speed microinstruction performance and external memory access. The external memory is divided into tables differing structurally but such as to be accessed in uniform manner by the internal addressing unit.

Integrated processing unit, particularly for connected speech

The device obtains several characteristic parameters from a standard sentence said by a speaker and compares them with average parameters of the same speaker stored in an internal memory and previously calculated. According to the comparison, it obtains a probability value that the sentence spoken belongs to that speaker and compares the value with a threshold normalized to the average parameter variance by a threshold calculation circuit. If the threshold is overcome, the device considers the speaker verified. A circuit determines the real instants of sentence beginning and end using a noise-adaptive threshold in order to limit between these two instants the time interval over which characteristic parameters are to be calculated. A circuit aligns as to time the characteristic parameters just calculated to the parameters of a reference sentence, obtaining standard lengths of the sounds composing the sentence spoken. A variable probability threshold is controlled by the standard deviations of the histogram of the average of the characteristic parameter vectors.

Device for speaker's verification

An electronic data processor includes a computing unit CPU carrying out a main program on the basis of data stored in a central memory MC and transferred to it from a mass memory MM under the control of an ancillary program or 'bootstrap' prerecorded in an external unit UE. The latter comprises a read-only memory RP storing the ancillary program, another read-only memory RM containing a set of microinstructions sequentially read out under the control of an address counter CRM to carry out the word-by-word transfer of the ancillary program to the central memory MC, and various components LCM, LSA, CFD for checking the correct performance of these operations and halting the transfer in the event of a malfunction while emitting an alarm signal.

Device for automatically loading the central memory of electronic

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Rosta, Italy

Alberto Ciaramella