A speech encoder is disclosed, in which, of the DCT coefficients after the discrete cosine transformation, a coefficient which has a large absolute value and exerts great influence on the tone quality is selected and encoded and zeros are inserted into the other unselected coefficients, so that selective encoding is carried out which does not seriously deteriorate the tone quality even when the coding rate is 8 kbps or below. In another arrangement, about three to 16 different selection patterns...

A speech recognition system comprises a recogniser (2) for receiving speech signals from users. The recogniser (2) compares each received word with templates of words stored in a reference template store (3) and flags each template that corresponds most closely to a received word. The flagged templates are stored in a template store (11). The recogniser (2) compares the speech pattern from a given user of a second utterance of a word for which a flagged template is already stored in the template...

A speech coder includes an LPC analyzer, a difference signal generating section, a first code book, a second code book, and a multiplexer. The LPC analyzer divides an input discrete speech signal into signal components in units of frames each having a predetermined time length, and obtains a spectrum parameter representing a spectrum envelope of the speech signal. The difference signal generating section obtains a difference signal by dividing the frame into subframes each having a predetermined...

A personal use, low cost, portable speech prompter which is light in weight and small in size. The speech prompter includes a support frame on which is mounted a light box with a horizontal translucent top wall. A transparent film with a speech printed thereon is slidably mounted, upside down, on the light box top wall. An image of the speech printed on the transparent film is reflected upwardly to a see-through view screen which reflects the speech image rearwardly along a line of sight between...

A speech encoder circuit of a waveform coding system. An analog speech input signal having coded data therein is received by a buffer and split into two branches. In a first branch the input signal is applied to a subtractor of an adaptive predictor to obtain a predicted residual signal subjected to an orthogonal transformation in a discrete cosine transform unit to convert the residual signal into a frequency domain of each of the frames of the individual blocks. An adaptive encoder in the firs...

A speech codec includes a drive sound source generating circuit in which, in a case of a voiced sound speech, a pulse pattern signal corresponding to a pitch-scale, drive sound source signals stored within a newest predetermined past time period and a noise signal are multiplied by predetermined gains, respectively, and then, added to each other so as to generate a drive voiced sound source and, in a case of an unvoiced sound, drive sound source signals stored within a newest predetermined past ...

A speech scrambler is disclosed, in which a frequency spectrum obtained by an orthogonal transform of a time domain signal is divided into a plurality of blocks in the frequency domain. One of the blocks which has energy less than a predetermined value is adaptively replaced by a dummy spectrum. The resulting spectrum is rearranged in accordance with a predetermined rule. The frequency spectrum is subjected to an inverse othogonal transform to obtain a time domain signal for transmission. The or...

A phonetically-driven speech synthesizer and method substantially entirely embodied in a programmed microprocessor. Information indicative of control parameters for each of a plurality of phonemes is stored in a phoneme parameter matrix and selectable by phoneme code. Time-invariant programming controls operation during successive operating cycles of equal time duration to obtain parameter information in a predetermined sequence for each selected phoneme, update control signals as a function of ...

A voice subtractor/recognizer which prevents interference from a voice output device by inputting via one input device both a sound to be recognized and any sound being output by the output device, and inputting at a second input device a signal representing the output of the output device. The latter signal is analyzed, and the result is used to inversely filter a signal representing the sounds input via the first-mentioned input device.

In a speech recognition system disclosed herein, acoustic speech waveforms are initially analyzed to obtain, at successive sample times, digital frames of speech information. This initial analysis may, for example, be performed by multi-channel filtering or linear predictive encoding. Stored in the apparatus is a list of representative standard frames, represented by coded indices, together with a table of difference values which represent the vector distances between each standard frame in the ...