Abstract: An improved arrangement for providing cathode heating current in a visual display wherein pulses of heating current are sequentially applied at brief intervals, the magnitude of the current and the intervals being coordinated with the cathode thermal inertia so as to maintain cathode temperature within an operative range during the off periods, and wherein potentials for activating the display are applied during such off periods.

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: A digital-to-analog driver capable of driving a speaker or other voice coil means and implementable using field effect semiconductor devices is disclosed. A plurality of switching field effect semiconductive constant current sources each having a control electrode and two current carrying electrodes are coupled in parallel at the current carrying electrodes thereof. Each switching field effect constant current sources preferably includes a field effect load device and a field effect switching device, the aforementioned control electrode preferably being the gate of the switching device. The respective width to length ratios of the active areas under the gates of the devices differ by a factor of two from each other. Therefore, the width to length ratio of the gates of a third one of the souces is twice the width to length ratio of the gates of a second one of the sources and four times the width to length ratio of the gates of a first one of the sources, and so forth.

Abstract: Disclosed is an electronic calculator having a data entry unit for inputting numeric data, expressions such as parentheses and hierarchal mathematical commands, an arithmetic unit for performing arithmetic operations on the numeric data, a memory for storing the numeric data and associated hierarchal mathematical commands inputted via the data entry unit and logic circuitry for enabling the arithmetic unit to perform arithmetic operations on numeric data inputted via the data entry unit within a pair of parentheses, the logic circuitry enabling the arithmetic unit to perform a higher order hierarchal mathematical command before a lower order hierarchal command eventhough the higher order command is received after the lower order hierarchal mathematical command.

Abstract: A circuit and method for actuating a display, especially a liquid crystal display, and a keyboard using a common set of conductors. The circuit includes circuits for generating appropriate display potentials, scanning pulses and sensing the scanning pulses. Certain of the display potentials applied to the display device are also applied to the keyboard. Certain of these potentials applied to the keyboard also have a scanning pulse superimposed thereon. Circuits for sensing the scanning pulses are associated with the circuits which generate the other potentials applied to the keyboard; these other potentials preferably float during the generation of the scanning pulses.By using the disclosed circuit, a calculator chip for actuating a multi-character position liquid crystal display and for scanning a keyboard may be packaged in a conventional twenty-eight pin package. By appropriately controlling the circuit, a keyboard can be scanned with negligible effect on the liquid crystal display device.

Abstract: An electronic phase locked loop circuit including a variable period sawtooth generator. The sawtooth generator receives digital reference clock signals and in response thereto generates sawtooth-shaped signals having the same period as said reference clock signals. A sample and hold circuit samples the sawtooth-shaped signals in response to one logical state of a sampling clock. A voltage controlled oscillator is coupled to the output of the sample and hold circuit and oscillates at a frequency proportional to the magnitude of the held sample. A feedback circuit generates the sampling clock by coupling the output of the voltage controlled oscillator to the sampling input of the sample and hold circuit.

Abstract: The invention defines a technique for assemblying all the parts of an electronic unit, for example a hand held calculator, directly on a plastic chassis without using individual printed circuit boards for various circuits of the calculator. Such parts of the calculator as the calculator chip, the display and the keyboard are all mounted on or formed on the plastic chassis in such a manner that only a cover has to be put over the plastic chassis to complete the calculator.

Abstract: A system for displaying character and graphic information on a color video display utilizes a unique memory architecture. A display memory having a plurality of addressable words corresponding to character positions on the display is utilized to store the digitally coded image signals generated by the processor. A digital processor generates digitally-coded signals indicative of a plurality of character or other graphic color images which are to be displayed on the color video display. Contiguous addresses of the display memory are developed by counters which are also used to generate horizontal and vertical sync signals for the display. A plurality of sets of characters with a plurality of characters per set are stored in a character generator memory. Each word of the display memory is formatted as two bytes. A character memory is provided separately from the display memory, and is addressed by the first byte of the display memory word.

Abstract: A printhead alignment mechanism is used in a non-impact type printer, such as a thermal printer for use, typically, in an electronic calculator. The printhead may pivot in a direction around an axis that is orthogonal to the axis of rotation of the print roller over which the printing medium is driven. The printhead may also pivot in a direction around an axis parallel to the axis of rotation of the print roller. This enables the printhead to follow small irregularities in the printing medium and the print roller. Substantially even pressure is thereby applied across the printhead to provide uniform printed characters.

Abstract: Described is a printer mechanism which includes a platen rotatably mounted above a base, a medium upon which printing is to be accomplished and a printer unit disposed in printing relationship to the medium and the platen. A holder holds the printer unit and includes a ball and socket assembly for permitting the holder and printer to pivot about first and second orthogonal axes with respect to the platen. The holder also includes a projection which projects into a channel for inhibiting the holder and the printer unit from pivoting about a third axis, the third axis being orthoganol to both a first and second axes. The channel and an end of the ball and socket assembly are attached to the base. The printer unit is preferably of a non-inpact type such as a thermal printer unit which is mounted on a ceramic substrate for instance. The holder is urged toward the platen by means of a spring, which is attached to the holder and to the base.

Abstract: Disclosed is a memory system for storing digital data; the memory system of the type which may be implemented, for instance, in an electronic microprocessor or calculator system. The memory comprises an array of transistor memory cells arranged in columns and rows. Column conductors are provided for supplying digital information to each column of such cells and row conductors are provided for enabling each row of cells to store digital information being received on the column conductors. A commutator is provided for successively supplying enabling signals to the row conductors and another commutator is provided for successfully connecting the column conductors with an input/output bus in the memory system. The provision of the commutators with the array of memory cells causes the data, when stored as a word of data, to occupy a register arranged in essentially a diagonal pattern through the array.

Abstract: An electronic calculator or microprocessor system of the type preferably having keyboard input and a visual display is provided with a semiconductor chip having a memory for storing instruction words, an arithmetic unit, an instruction word decoder for controlling the arithmetic unit in response to instruction commands read out of the instruction word memory and a combined data and flag bit storage system. The combined data and flag bit storage system provides for the storage of flag bits with an associated numeric data word in a single register. Certain of the stages of the register are preferably dedicated for use as flag bit storage and certain other stages of the register are dedicated for use as numeric data storage. The arithmetic unit is preferably operable in a first mode for performing arithmetic operations in binary coded decimal format for the numeric data and in a binary format for the flag bits.

Abstract: A completely electronic system for recording and subsequently displaying still life pictures includes an optical-electronic transducer for generating electronic signals responsive to an optical image. The signals are stored and subsequently applied to a visual display. Means are provided for applying the signals at a scan rate synchronized with the scan rate of the display to effect a stationary display of the optical image. Preferably, the display is a conventional television set.

Abstract: A transceiver includes a first mixer and a detector in the receive signal path and a second mixer and modulator in the transmit signal path, all of which are coupled to and are operated by programmable counter circuits clocked by a single reference frequency generator. In one embodiment, a charge transfer device filter, which is connectable to both the receive and transmit signal paths by a switch and which has an adjustable bandwidth and center frequency, is also coupled to and operated by a programmable counter circuit which is clocked by the single reference frequency generator.

Abstract: A radio receiver receives input signals comprised of a plurality of frequency bands lying respectively within a plurality of non-overlapping frequency channels. The signals include an itermittently present reference frequency signal. The radio receiver includes an autolock circuit for measuring the frequency of the intermittently present carrier and for generating digital signals indicating its frequency. A digital processor has inputs coupled to receive the digital signals for calculating in response thereto a selectable demodulating frequency dependent upon the frequency of the intermittently present carrier.