In a synthesiser which, for each sampling period, reconstitutes a language element by means of three sinusoidal components obtained with the help of variable-frequency generators and variable-attenuators, those components are simultaneously subject to predetermined rephasing operations carried out at an auxiliary frequency identified with the pitch frequency (or frequency of vibration of the voice) at the time of emission of vowels or voiced consonants. This auxiliary frequency is delivered by a...

A digital device to make speech in a helium atmosphere more intelligible includes a recirculating storage and an analog to digital converter which periodically samples the speech and the digital samples are loaded into the storage at a rate determined by a load counter. An unload counter continuously operating at a predetermined slower rate than the load counter unloads the stored digital representations of the speech and a digital to analog converter converts it back to an analog signal. The an...

A speech scrambler for use with conventional mobile communications systems is described including signal gating circuitry so that it may be operated by a simple push button transmitter switch and in the scramble or clear modes without modification of the equipment with which it is used.

An audio frequency gate is disclosed for use in an electronic PABX. In particular, the gate enables the efficient transmission of speech and multi-frequency tones between components which are controlled by dc potentials without disrupting associated dc controls.

A dispersed vector generator used for a speech encoder or a speech decoder includes a pulse vector provider that provides a pulse vector having a signed unit pulse on one element of a vector axis. A dispersion pattern determiner determines a dispersion pattern of a set of waveforms defined before a start of encoding or decoding. A dispersed vector generator convolutes the pulse vector and the determined dispersion pattern to generate a dispersed vector. A length of the waveforms is shorter than ...

A target vector is coded by multi-stage vector quantization. A first stage of the coding of the target vector is performed using a first code vector stored in a first codebook. A scalar associated with a code of each first code vector is stored in an amplifier storing section. A third code vector is determined by multiplying a second code vector stored in a second codebook with the scalar, calculating a distance using the target vector, the first code vector and the third code vector, and perfor...

A code excited linear prediction speech decoder is provided. An adaptive codebook generates an adaptive code vector. A random codebook generates a random code vector. A synthesis filter receives a signal based on the adaptive code vector and the random code vector, and performs linear prediction coefficient synthesis on the signal. The random codebook includes a pulse vector provider that provides a pulse vector having a signed unit pulse, a comparator that compares a value of adaptive codebook ...

A speech digitizer is disclosed including an analyzer for generating power and filter coefficient parameters representative of an analog speech waveform. The digitizer also includes a pitch detector for generating a digital pitch parameter substantially representing the fundamental periodicity of the waveform and including range restrictor means for restricting the pitch signal to a range of pitches within a predetermined tolerance if the average pitch of the periodicity signal is below a predet...

This invention relates to speech therapy wherein a speech teaching aid is provided comprising at least one two dimensional frontal outline of human face, the outline including a representation of vocal apparatus corresponding to the configuration of the vocal apparatus of a person when a particular phonetic sound is being made. The aid may be applied to a mirrored surface so that a comparison can be made by the patient of his facial expression with that of the aid.

A method of transmitting speech signals with reduced bandwith requirements. With this invention an original speech signal is first converted to a textual representation, and a facsimile of the original speech is determined from the textual representation. Then a minimum error turn is derived from the difference between the original speech signal and the facsimile of the original speech signal. The minimum error turn is then compressed, and it is this compressed minimum error turn, along with the...