Abstract: An LSP synthesizer (Line Spectrum Pair) includes an LSP voice synthesizer digital filter arranged for parallel operation upon voice parameters and excitation information, to obtain an LSP synthesized sound. The LSP voice synthesizer digital filter includes at least a parallel multiplier and a parallel adder. The parallel multiplier divides data into a set of upper bits and a set of lower bits and multiplies the upper and lower bits separately at specified different timings. The multiplication results are supplied to a delay circuit which adjusts timings of the multiplication results. These multiplication results are synthesized by the parallel adder to obtain a single piece of data.

Abstract: An adaptive predictive coding (APC) and adaptive kit allocation (ABA) system which splits a speech signal into a plurality of bands, subjecting each signal to adaptive predictive coding and adaptively changes quantization characteristics in the adaptive predictive coding so that quantization noise may become small. An average amplitude (not average power) of the signal of each band is detected for each temporal sub-interval, and a quantization bit number and a quantization step size are adaptively determined from the average amplitude for each sub-interval, thereby permitting reduction of the quantity of hardware used.

Abstract: A speech recognition system for an automotive vehicle can effectively eliminate noise generated by vehicle engines, and comprises a group of bandpass filters the pass bands of which are approximately from 500 to 600, from 900 to 1200, and from 900 to 2200 Hz, for effectively passing only the speech sound formant frequencies while eliminating the major frequency components of engine noise less than 500 Hz, in addition to the conventional speech recognizer. Further, it is desirable to provide the speech recognition system with a high-frequency compensator for enhancing the voltage level of the high frequency components of the electrical signal representing spoken instructions at a rate of 20 dB or more per decade increase in frequency and/or a plurality of notch filters fo sharply reducing the major engine noise frequency components at 200, 400, and 800 Hz.

Abstract: Pole encoding of a linear predictive all-pole model of speech is accomplished by first finding poles up to the number required for good prediction (e.g., ten). These poles are extracted from the LPC predictor polynomial, using, e.g., a slightly modified Bairstow method. Those poles having a sufficiently narrow bandwidth (i.e., those sufficiently near the unit circle) are separately encoded, since these poles generally correspond to perceptually important formants. The remaining poles are lumped together to form a residual polynomial. The residual polynomial is then transformed to produce reflection coefficients, and all reflection coefficients above the first two are discarded. This provides an efficient spectral-shaping polynomial of a reduced degree. Thus, pole encoding is made possible using a reduced and adaptively varied bit rate.

Abstract: Improved efficiency in allocating bits to individual ones of a plurality of sub-band signals (or amplitude coefficients) is realized by employing a so-called template matching technique. A plurality of the most likely to occur bit allocation patterns and a corresponding plurality of templates including representations of a prescribed characteristic of the sub-band signals that would generate a corresponding one of the bit allocation patterns are stored for later use. Selection of a bit allocation pattern for use in encoding and/or decoding the sub-band signals is effected by matching in accordance with a given one of the stored templates to representations of the prescribed characteristic of the sub-band signals presently being encoded. In one example, the prescribed characteristic is a power estimate and the matching criterion is a minimum rate distortion criterion.

Abstract: The detection of voice (speech) signal presence in input signal-plus-noise is improved by more accurate determination of the decision threshold, which is determined by first finding a medium-length interval consisting of noise-signal-noise (no-signal, signal, no-signal), then calculating a histogram (energy probability distribution) for the interval, then finding the maximum value of variance of the histogram as the optimal threshold, plus an arbitrary offset.

Abstract: A voice-controlled elevator security system. Access to an elevator system servicing a plurality of landings of a structure is controlled by comparing a voice signal of a potential user of the elevator system with stored voice signals of all authorized users. The comparison is accomplished by first digitizing the potential user's voice signal and comparing it, on a bit-by-bit basis, with a digital representation of the voice signals of all authorized users. Various criteria can be established for determining the number of binary bits that must agree to conclude that the potential user is an authorized user. Once this determination has been made, the authorized user can initiate car call signals for those landings to which the authorized user is permitted access.

Abstract: In a code conversion system comprising an encoder and a decoder in combination, the encoder comprises an input terminal for receiving a multi-level time series signal having at least three signal levels subject to a variation of occurrence frequency of levels, a circuit for detecting the highest occurrence frequency signal ("HOFS") level of said multi-level time series signal and generating a first code representative of the run-lengths of said HOFS level, a circuit for generating a second code representative of the individual levels of said multi-level time series signal, and a circuit for combining said codes from said first and second code generation circuits on the time series, and wherein the decoder comprises a circuit for separating the first and second codes and decoding the separated first and second codes into the original multi-level time series signal.

Abstract: A speech recognition system for an automotive vehicle which can record or recognize spoken instruction phrases reliably even when engine noise increases high within the passenger compartment. When the engine begins to operate, the gain of an amplifier of a speech input section or the threshold level of a voice detector is so switched as to reduce the sensitivity to spoken instructions. As a result, the driver must necessarily utter a spoken instruction in a louder voice and thus the proportion of noise level to spoken instruction signal level is reduced. The system according to the present invention comprises engine operation detecting means, an analog switch, two amplifiers or two multipliers, etc. in addition to the conventional speech recognizer.

Abstract: A speech recognition system includes speech presence detection which uses a first level threshold of ambient noise/silence above which speech start is decided for a signal. Speech end is decided when the signal falls to a second threshold equal to the first, unless a predetermined time interval of speech is exceeded after start, causing a corrected second threshold to be calculated and used.

Abstract: A speech recognition and actuator system for auto device control includes a recognition switch which when operated a first time activates the system to accept a spoken command, and if operated a second time within a predetermined interval T1 (approximately 2 seconds) stops the actuation and awaits a new command. Additional timers provide interval T2 for a stop command, and T3 for enabling the speech recognizer. The system may also include a reset switch when operated returns the actuated device to its original state.

Abstract: This speech signal recognition system compares the two-dimensionals pattern (time sequence of feature vectors) of an unknown signal to prestored standard references patterns for recognition, thus forming a corresponding two-dimensional comparison pattern of points of elemental Hamming distance differences. The sum of the pattern point distances is the similarity measure. To improve accuracy, partial patterns are selected (or "masked") and tested sequentially, and the point values weighted relative to their location within the mask. The mask may be rectangular or oblique.

Abstract: A microcomputer system includes a main processor, a memory and a direct memory access controller (DMA) effective to control direct data transfer between the memory and input/output devices on channels. Bus control for data transfer is switchable between the DMA and processor by a hold request/acknowledge handshaking sequence between the DMA and processor. A control line from the channels is activated by a peripheral processing device on a channel when it wishes to gain control of the busses for data transfer. Logic means coact with the handshaking sequence to determine which device gains control of the busses. This logic is responsive to the DMA address enable output (AEN), the hold acknowledge output of the main processor (HLDA) and the channel control line output (-MASTER). When all these are deactivated, control passes to the main processor, when AEN and HLDA only are activated, control passes to the DMA controller and, when all three are activated, control passes to the peripheral processing device.

Abstract: A voice synthesizer is disclosed for simulating a voice singing the lyrics of a song. The synthesizer comprises a phoneme speech synthesizer in which the phonemes are sounded at a pitch controlled by the keys or notes played on a musical keyboard. The tempo of the sung lyrics is controlled by the tempo at which the keys of the keyboard are played.

Abstract: A voice-responsive mobile status unit for operation in a communication system having at least one mobile transceiver and at least one base transceiver is disclosed. A speech recognition circuit is provided for receiving and converting predetermined spoken phrases into corresponding coded outgoing digital data signals if a predetermined spoken message occurs within a predetermined time interval after the occurrence of a predetermined spoken keyword. The digital data signals are transmitted to the base transceiver by the mobile transceiver. The mobile status unit further has a speech synthesizer for receiving coded incoming digital data signals being transmitted by the base transceiver and received by the mobile transceiver. The speech synthesizer converts the incoming, coded, digital data signals into electrical signals representative of speech.

Abstract: In one embodiment of this invention, a uniquely designed switched capacitor multiplier/adder (129) is provided which also functions as a digital-to-analog converter in a single subcircuit. The multiplier/adder, in a single operation, multiplies an analog voltage by a binary coefficient, and sums this product with a second analog voltage. The use of this unique subcircuit significantly reduces the space requirements for the construction of, for example, a speech synthesis circuit utilizing linear predictive coding over prior art circuits. This invention provides a novel structure and method which minimizes error components in the synthesized speech signal due to voltage errors inherent in the use of analog sample and hold circuits which are used to store the forward and backward prediction errors utilized in the linear predictive coding technique. Using the method of this invention, the inherent error components are alternatively inverted and not inverted upon each clock cycle of the multiplier/adder.

Abstract: A reconfigurable lattice filter is employed to permit the same circuitry to function as a speech synthesizer and as a speech analyzer or recognizer. The lattice filter can be configured both as an all-pole filter (for synthesis) and as an all-zero filter (for analysis), with the choice being determined by the state of an analysis/synthesis signal (i.e., mode control signal) provided thereto. The connections between various elements in the circuitry are controlled by the analysis/synthesis signal, also.In synthesis mode, partial correlation coefficients are supplied to the filter from a microprocessor. The filter is excited by a one of a number of stored patterns simulating a glottal pulse for voiced sounds and by a pseudo-random noise generator for unvoiced sounds.In analysis mode, appropriate feedback control paths are enabled so as to provide to the filter coefficients which change in response to changes in the input speech waveform.

Abstract: A speech presentation method and apparatus which afford a dual multiple point matrix presentation of speech as patterns of points corresponding to codes representing speech phonemes and the characteristic mouth formations that produce the phonemes. Spatial patterns may be presented in either tactile or visual form, or both, from the output of a microcomputer speech analyzer that analyzes speech in real time, from a keyboard that generates phoneme- and mouth form-representing signals, or from a memory device that reproduces pre-recorded spatial patterns. The speech analyzer may be incorporated into an armband with a pair of tactile stimulator matrices to provide an unobtrusive prosthetic device for heating-handicapped individuals. A modified 16 mm projector records spatial patterns on punched film and projects the patterns onto a display to provide a visual presentation.

Abstract: In a pitch synchronous speech synthesizer, an output signal from a pitch phase detector is applied to a delay circuit in a digital filter portion to initialize the output contents of the delay circuit at zero for each pitch period. In this manner the sequence of neighboring frames is smoothed.

Abstract: This speech recognition system uses a converted-spectrum for comparison of unknown and prestored reference signals. The comparison distance is modified by a weighting factor W to emphasize differences. A straight line approximation of the short term spectrum provides a datum against which the original spectrum is differenced to provide the converted spectrum, and provide deviation signs which are used to modify an initial prestored weighting factor P to form W.