FR2611969A1

FR2611969A1 - Voice recognition device

Info

Publication number: FR2611969A1
Application number: FR8702608A
Authority: FR
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-02-24
Filing date: 1987-02-24
Publication date: 1988-09-09

Abstract

The invention relates to a device making it possible to count the time which elapses between two passages of the voice signal through zero, and to allow the microprocessor fitted to the system to decide on the recognition of the word or phrase articulated. It consists of an amplifier for amplifying the signal output from the microphone, of a low-pass filter, of a high-pass filter allowing the passband of the signal to be reduced to between 250 Hz and 4500 Hz, of a comparator and of voltage reference fixed to a few millivolts (resistive divider bridge), of a counter and its clock, as well as of a microprocessor which allows recognition of the word or the phrase articulated. The present device is particularly intended for voice recognition.

Description

La présente invention concerne un dispositif conçu pour mettre en forme le signal vocal provenant d' un microphone et pour reconnaitre la voix humaine . De tels dispositifs existent actuellement et fonctionnent plus ou moins bien, ils sont le plus souvent basés sur la détection du nombre de passages par zéro du signal vocal, le codage MIC ( modulation par impulsions codées) , le codage LPC ( codage par prédiction linéaire) . Ces dispositifs complexes utilisent des algorithmes ( programmes) longs et délicats tels que la transformée de Fourier par exemple, et occupent une place considérable en mémoire d' ou une capacité moindre pour la phase de reconnaissance en elle même . The present invention relates to a device designed to format the voice signal coming from a microphone and to recognize the human voice. Such devices currently exist and work more or less well, they are most often based on the detection of the number of zero crossings of the voice signal, MIC coding (pulse code modulation), LPC coding (linear prediction coding) . These complex devices use long and delicate algorithms (programs) such as the Fourier transform for example, and occupy a considerable place in memory or less capacity for the recognition phase in itself.

Le dispositif selon 1' invention permet de pallier ces inconvénients de par le fait qu' il est basé sur un principe nouveau
L' appareil possède tout d' abord un amplificateur opérationnel monté en non inverseur avec un gain adapté qui permet d' amplifier le signal issu du microphone . Ensuite le signal est filtré grace à deux filtres à 40 décibels par décades 1' un passe haut, 1' autre passe bas qui permettent de limiter la bande passante du signal entre 250 et 4500 Hertz.Un double filtrage est éffectué grace a la decroissance rapide de ces filtres , en effet le signal de haute fréquence 4500 Hertz et plus dans notre cas est atténué et passe au dessous du seuil pour lequel le comparateur passe au niveau haut , ce systeme a 1' avantage de produire une coupure nette à 4500 Hertzs
Le signal débarrassé des fréquences indésirables est dirigé vers un ampli opérationnel utilisé en comparateur. Ce comparateur une référence à quelques millivolts fixée par un pont résistif diviseur de tension ( ce pont transforme le 5 volts sur son entrée en quelques millivolts sur sa sortie ) .A la sortie du comparateur il est obtenu un signal carré de période identique à celle du signal vocal présent à la sortie des filtres
De plus le comparateur posséde une sortie au niveau TTL ( Transistor transistor logic ) grace à son alimentation 5 volts, ceçi lui permet de piloter un compteur ( circuit intégré ) qui peut être de 8 bits ou 16 bits ou même 32 bits,
Le compteur est mis en fonctionnement lorsque le signal issu du comparateur est au niveau haut et l'arrente lorsqu'il est au niveau bas, 1 inverse est également possible.The device according to the invention overcomes these drawbacks by the fact that it is based on a new principle
The device first of all has an operational amplifier mounted as a non-inverter with a suitable gain which allows the signal from the microphone to be amplified. Then the signal is filtered thanks to two filters at 40 decibels per decade 1 'a high pass, the other low pass which allow to limit the bandwidth of the signal between 250 and 4500 Hertz. A double filtering is effected thanks to the fast decrease of these filters, in fact the high frequency signal 4500 Hertz and more in our case is attenuated and goes below the threshold for which the comparator goes high, this system has the advantage of producing a clean cut at 4500 Hertzs
The signal freed from unwanted frequencies is sent to an operational amplifier used as a comparator. This comparator a reference to a few millivolts fixed by a resistive voltage divider bridge (this bridge transforms the 5 volts on its input into a few millivolts on its output). At the output of the comparator, a square signal with the same period is obtained as the voice signal present at the filter output
In addition, the comparator has an output at TTL level (Transistor transistor logic) thanks to its 5 volt power supply, which allows it to drive a counter (integrated circuit) which can be 8 bits or 16 bits or even 32 bits,
The counter is put into operation when the signal from the comparator is at the high level and arrives when it is at the low level, 1 reverse is also possible.

Le compteur est connecté une horloge qui doit fonctionner d' après le théorème de Shanon à plus de deux fois la fréquence la plus élevée du signal vocal. La fréquence du compteur sera obtenu par un quartz relié au dit compteur. Le compteur compte le nombre de coups d' horloge entre deux passages par zéro du signal vocal ce qui lui permet de déterminer avec exactitude le temps écoulé entre deux passages par zéro du signal vocal
Enfin le compteur devra être compatible avec le bus d' un microprocesseur de préférence un 32 bits, afin de pouvoir prendre les décisions utiles et reconnaitre les mots et les phrases qui seront prononcées devant le microphone ceci grâce à 1' algorithme adéquat.The counter is connected to a clock which must operate according to Shanon 's theorem at more than twice the highest frequency of the voice signal. The frequency of the counter will be obtained by a quartz connected to said counter. The counter counts the number of clocks between two zero crossings of the voice signal which allows it to accurately determine the time elapsed between two zero crossings of the voice signal.
Finally the counter will have to be compatible with the bus of a microprocessor preferably a 32 bits, in order to be able to take the useful decisions and to recognize the words and the sentences which will be pronounced in front of the microphone this thanks to 1 adequate algorithm.

Le dispositif peut être réalisé selon une forme de réalisation préférentielle sur une plaque en résine d' époxy
La figure I représente le schéma électronique de 1 invention
Le repere A marque 1' entrée microphone du systeme
Le repere B marque 1' amplificateur non inverseur
Le repere C marque le filtre analogique passe bas à 40 décibels par décades
Le repere D marque le filtre analogique passe haut à 40 décibels par décades
Le repere E marque 1' amplificateur opérationnel utilisé en comparateur
Le repere F marque la sortie du comparateur vers le microprocesseur et son horloge The device can be produced according to a preferred embodiment on an epoxy resin plate.
Figure I shows the electronic diagram of 1 invention
Mark A marks the microphone input of the system
The mark B marks the non-inverting amplifier
The mark C marks the analog low pass filter at 40 decibels per decade
Mark D marks the analog filter goes high at 40 decibels per decade
The E mark marks the operational amplifier used as a comparator
The mark F marks the output of the comparator to the microprocessor and its clock

Claims

CLAIMS 1) A voice recognition device characterized in that it takes into account the time taken between two zero crossings of the voice signal by counting the number of clock strokes between two zero crossings of said voice signal and that it allows the microprocessor which is connected to it to deduce therefrom, thanks to a specific algorithm, the frequency of the fundamental without having to go through complex analyzes The mark A marks the microphone input of the system. The mark B marks the non-inverting amplifier The mark C marks the analog filter at 40 decibels per decade (low oasse filter) The mark D marks the analog filter at 40 decibels per decade (high pass filter). The E mark marks the operational amplifier used as a comparator. The mark F marks the output of the comparator at the TTL level, directed towards the microprocessor and its clock 2) Device according to claim nol characterized in that the system comprises a microphone for acquiring the signal 3) Device according to claim n01 characterized in that '' it includes an operational amplifier, mounted as a non-inverter and two filters at 40 decibels per decade, 1 'a low pass, 1' another high pass, to reduce the signal bandwidth between 250 and 4500 Hertzs 4) Device according to claim n01 characterized in that it includes a double filtering system, in fact, filters with high attenuation,

40 decibels per decade allow the signal level to drop below the threshold for which the comparator goes high when the frequency exceeds 4500 Hertzs, which has the effect of producing a clean cutoff from this frequency 5) Device according to the claim nO l characterized in that it comprises an operational amplifier mounted as a comparator, the reference of which has been placed a few millivolts from 5 volts by a resistive divider bridge

This comparator allows you to put the voice signal in square form, while keeping the period of the signal from the filters

The comparator output signal is placed at TTL level (transistor

transistor, logic) thanks to a 5-volt supply of said comparator

this comparator output signal can drive the counter 6) Device according to claim nO I characterized in that it includes an integrated circuit called counter which can be an 8 bit, a 16 or a 32 bit, which is connected to a clock, driven by a crystal operating at more than twice the maximum frequency of the voice signal

This counter is controlled by the comparator output signal, at low level,

the counter is inactive, at the high level the counter is active and counts the clock ticks present on its between clock

These two proposals can be reversed with the appropriate software

This system makes it possible to count the time which elapses between two zero crossings of the voice signal, therefore the microprocessor can deduce the iot or the sentence spoken in front of the microphone 7) Device according to claim n01 characterized in that the counter must be compatible with the bus of the microprocessor responsible for interpreting the signals received 8) Device according to claim n01 characterized in that it comprises a microprocessor, preferably a 32 bit which will be responsible for interpreting the signals, and translate the results into plain language