Abstract: An electronic hand-held, talking learning aid is disclosed. The learning aid includes a MOS speech synthesizer chip having an active surface area on the order of 45,000 square mils. The disclosed speech synthesizer chip includes a digital lattice filter, a voiced/unvoiced excitation circuit, a speech parameter interpolator, an input parameter decoder, a digital-to-analog converter and associated timing circuits. The learning aid is also provided with a microprocessor which functions as a controller for controlling the operation of the unit. A small speaker is driven by the digital-to-analog converter on the speech synthesis chip and a keyboard and display device are strobed by the microprocessor controller. Features include modes in which a speech synthesizer recites instructions or questions to the operator who must properly respond.

Abstract: An electronic handheld talking translator including a speech synthesis integrated circuit device. The speech synthesis integrated circuit device includes a digital filter, a voiced/unvoiced excitation circuit, a speech parameter interpolator, an input parameter decoder, a digital-to-analog converter, a speaker and associated timing circuits. A non-volatile memory stores digital data representative of the correct spellings of selected words in a foreign language and the model vocal tract control data necessary to control the speech synthesis circuit in a manner to cause the selected words to be audibly pronounced by the translator.

Abstract: A speech synthesis circuit is provided with a variable frame length data converter and the speech synthesizer is preferably integrated on an integrated circuit chips. The variable frame length data converter reduces the amount of data required to synthesizer human speech at a given quality level. Preferably, a full frame of data includes, a pitch parameter, an energy parameter, a repeat bit and a plurality of speech coefficients. Each parameter or coefficient has a preselected length, but each frame has a variable number of parameters or coefficients associated therewith. The parameters and coefficients are encoded and a particular code of the pitch parameter indicates that the speech is to be unvoiced. An unvoiced frame includes fewer coefficients that a voiced frame and the converter detects this particular pitch parameter and automatically sets the unsent coefficients to zero.

Abstract: A didactic device for providing a learning experience and/or entertainment by serving as a learning aid to improve penmanship and drawing skills. The didactic device combines an optical image processing system with a speech synthesis system, wherein a drawing surface is provided in registration with the field of view of an optical imager. The user of the didactic device is requested either visually via a display mounted on the housing of the didactic device in proximity to the drawing surface or verbally via speech synthesis electronics to write or draw something on the drawing surface. When the user has completed the assignment by drawing indicia on the drawing surface, the image processing system, which includes an imager chip, a matrix memory in which signal data output from the imager chip is stored, and a data processor having an object recognition comparator, is actuated.

Abstract: An adaptive filter suitable for speech analysis which is constructable on a silicon chip. The filter has a single multiplier and a single adder in series together with appropriate registers or memories so that the output of the adder is either looped back to the adder itself or alternatively is looped, after a delay, to the multiplier so as to perform the operations of an all-zero digital lattice filter in computing a moving average, employing linear predictive coding. Another register provides the multiplier with the constant values typically associated with lattice filter coefficients. Preferably the multiplier is an M-stage pipeline multiplier so as to reduce the area necessary for its incorporation on a silicon chip. The filter accepts digital samples of the voice input and outputs a compressed data representation of the input.

Abstract: An electronic learning aid for interactive operation with an operator with capabilities for the synthesis of a tone or sequence of tones. The tone, in the alternative, is used to either prompt the operator to respond in like fashion or is in response to the operator's input of a tone or sequence of tones. In this fashion the learning aid selects a tune to be synthesized and communicates this tonal sequence to the operator who responds by attempting to mimic the sequence. An alternate operation of the learning aid is for the operator to audibly input a tone sequence and for the electronic learning aid to attempt to mimic the sequence of tones.

Abstract: Speech synthesis system implementable in an integrated circuit device capable of converting frames of speech data at a variable frame rate into analog signals representative of human speech. The frames of speech data comprise digital representations of values of pitch, energy, filter coefficients and coded frame rate data. The speech synthesis system includes a linear predictive coding filter as a speech synthesizer which utilizes the speech data at a varying frame rate to produce digital speech signals representative of human speech. Frames of digital speech data including coded frame rate data are received by an input, with the frame rate data being decoded to control both the rate at which the incoming variable-length frames of speech data are accepted by the speech synthesizer and the number of interpolation calculations required to define interpolated speech values between adjacent incoming frames of speech data.

Abstract: An electronic learning aid in which the student supplies a problem to which the learning aid supplies a response. The response of the learning aid is sometimes correct and at other times incorrect, thus requiring the operator/student to respond as an educator of the learning aid. This educating of the learning aid by the student requires the ability to recognize the correct answer. Preferably, if the student recognizes the correct response, praise is given; otherwise, either the problem is explained to the student or the learning aid ventures another guess. This "educating" of the learning aid through the posing of problems from the operator allows the student to proceed at his own pace and yet tries the limits of his knowledge.

Abstract: A speech synthesis system utilizing a linear predictive filter. Voiced and unvoiced excitations are applied to the filter to produce a digital signal representative of human speech. The voiced excitation is provided by a repeating chirp function stored in memory. The unvoiced excitation consists of two excitation signals of opposite sign, stored in programmable memory and randomly addressed. The programmable storage of unvoiced excitation signals allows gain scaling between voiced and unvoiced excitation to be easily accomplished.

Abstract: A system using a digital filter for generating complex waveforms, such as human speech. The filter has a multiplier, an adder coupled to the output of the multiplier and various delay circuits coupled to the output of the adder. A latch memory is coupled to the output of one of the delay circuits. Switching circuits are provided for the output of the delay and the latch memory to inputs of the multiplier and the adder to selected times. Coefficients of the filter are preferably stored in a memory coupled to another input of the multiplier. The excitation signal is coupled to the adder in one embodiment and to the multiplier in another embodiment.

Abstract: A system incorporating an integrated circuit device or chip which digitally synthesizes human speech using a linear predictive filter. The linear predictive filter comprises a single filter stage only which contains a single multiplier for selectively multiplying a plurality of coefficients, initiating the multiplication of one coefficient at a time, by using a feedback loop with multiplexing techniques so as to input multiplexed signals to the multiplier--as contrasted to a cascade of filter stages. Thus, the single multiplier of the linear predictive filter is utilized repetitively to provide the calculations required. The system also includes a memory for storage of digital filter coefficients, a controller for selectively accessing the coefficients, and a speaker for generating audible sounds.

Abstract: Speech parameter signals may be coded to consist of fewer bits for data reduction in memory. In this system both coded and uncoded signals are stored with an associated control signal which controls selection of corresponding direct or decoder circuit coupling of memory output to a speech synthesizer.

Abstract: A speech synthesis circuit implementable in an integrated circuit device, capable of converting frames of data into analog signals representative of human speech. The frames of data are comprised of digital representations of values of pitch, energy and certain filter coefficients, which are stored in non-volatile memory. The filter coefficients are utilized to control a linear predictive filter which is excited by voiced and unvoiced excitations stored in non-volatile memory. A control circuit coupling the excitation signals to the linear predictive filter allows the operator to select an external excitation signal rather than precalculated stored excitation signals. Thus, the synthesizer may be utilized in a vocoder application, wherein a residual excitation signal transmitted from an analysis circuit may be utilized as the excitation signal.

Abstract: A speech synthesis circuit is provided with a variable frame length data converter and the speech synthesizer is preferably integrated on an integrated circuit chips. The variable frame length data converter reduces the amount of data required to synthesizer human speech at a given quality level. Preferably, a full frame of data includes, a pitch parameter, an energy parameter, a repeat bit and a plurality of speech coefficients. Each parameter or coefficient has a preselected length, but each frame has a variable number of parameters or coefficients associated therewith. The parameters and coefficients are encoded and a particular code of the pitch parameter indicates that the speech is to be unvoiced. An unvoiced frame includes fewer coefficients that a voiced frame and the converter detects this particular pitch parameter and automatically sets the unsent coefficients to zero.

Abstract: A method of communicating Digital Speech Data to a speech synthesis circuit. The data is compressed to on the order of 1000-1200 bits, per second for normal human speech. The speech synthesis circuit utilizes linear predictive coding techniques for producing high quality speech or other sounds.The data is preferably stored in a memory which is coupled to the speech synthesis circuit. The data has variable frame lengths; in the disclosed embodiment, four different frame lengths are described having frame lengths from four bits to forty-nine bits. The memory stores the variable frame length data and communicates the same to the speech synthesis circuit in response to certain control signals.

Abstract: Disclosed is an integrated circuit device or chip which digitally synthesizes human speech using a linear predictive filter. This device may be implemented using conventional processing techniques. For instance, when implemented in conventional P-channel MOS technology, the disclosed device or chip has an active area of approximately 45,000 square mils.

Abstract: A digital filter of the type which may be used in circuits for generating complex waveforms, such as human speech. The filter has a multiplier, an adder coupled to the output of the multiplier and various delay circuits coupled to the output of the adder. A latch memory is coupled to the output of one of the delay circuits. Switching circuits are provided for the output of the delay and the latch memory to inputs of the multiplier and the adder to selected times. Coefficients of the filter are preferably stored in a memory coupled to another input of the multiplier. The excitation signal is coupled to the adder in one embodiment and to the multiplier in another embodiment. In either embodiment, the digital filter may be implemented on a single integrated circuit chip.

Abstract: Improved fidelity and reduced computational requirements are achieved in a linear predictive coding (LPC) system that utilizes multichannel signal processing and reduced sampling rates. The input analog signal is divided by filters into multiple, contiguous, substantially equal bandwidth signal components and each component is digitized and processed by a separate standard LPC transmit-receive system. Each transmit-receive system operates at a sampling rate that is equal to the normal sampling rate for the signal being processed divided by the number of channels or signal components used. The received signal components are filtered, converted to analog, and summed.