Abstract: A converter circuit for converting binary logic signals from a CMOS circuit into binary signals for an ECL circuit. Two output transistors in the converter circuit are connected in parallel between the V.sub.DD CMOS supply voltage and the output of the converter circuit. The resistance across the drain-to-source terminals of the output transistors form a voltage divider network with a pulldown resistor in the ECL circuit. In one embodiment, one of the output transistors is enabled by a logic "1" from the CMOS circuit and the other is enabled only by a logic "0". In another embodiment, one output transistor is always enabled and the other is enabled only by a logic "0" from the CMOS circuit. In both embodiments, the effective resistance across the parallel transistors is different for a logic level "1" and a logic level "0", so that the voltage at the output is also different.

Abstract: An electronic circuit for converting trinary level input signals on a first line into binary level signals on two or more output lines using contemporary CMOS field effect transistor integrated circuits. According to one embodiment, conversion is accomplished using two CMOS inverters each asymmetrically configured to exhibit transconductances which differ by a factor in excess of 5. In another form, the circuit provides hysteresis through positive feedback to limit binary output state perturbations attributable to trinary signal level input noise. The invention also encompasses the use of decode logic and logically combined delay elements to eliminate "glitches" and facilitate selective enablement of the decoded states representing the intermediate of the trinary input levels.

Abstract: A standoff and retainer for use in mechanically and electrically connecting two or more printed circuit boards in a parallel spaced type arrangement. The metallic standoff is constructed in the form of a sleeve partially closed at one end. The plastic retainer is also formed in the shape of a sleeve but includes a male connector at one end. The standoff is attached to a printed circuit board by advancing the connector end of the retainer into the open end of the standoff until the connector snaps into engagement with the hole in the partially closed end wall of the standoff and a mounting hole in the printed circuit board.

Abstract: An analog-to-digital inverter includes successive approximation control logic for generating ten-bit binary numbers, a digital-to-analog converter (DAC) having a resistor string and a weighted-capacitor array for converting the ten-bit binary output of the control logic to a known analog voltage, and an analog comparator for comparing the output of the DAC to a reference voltage provided via a tap to the mid-point of the DAC resistor string. The unknown analog voltage input to the ADC and the reference voltage are provided to the capacitor array to precharge the array to a voltage equal to the reference voltage minus the unknown analog voltage. The output of the DAC is therefore equal to the known analog voltage plus the reference voltage minus the unknown analog voltage.

Abstract: A video display controller for controlling the display of characters stored in a bit plane memory. The characters to be displayed are arranged in the bit plane memory in a set number of scan lines with a set number of data bits in each scan line. Attribute bits are included in one scan line of data bits in each character to be displayed. The controller includes a data bus for receiving data from the bit memory plane in bytes, each of which includes data bits of one scan line. Each data byte from the data bus is clocked into a shift register, with the data byte shifted out of the shift register sequentially, one bit at a time. Attribute bytes are selected from the data bus and an attribute logic circuit applies the attribute bits to the sequential data bits of a corresponding character to be displayed.

Abstract: An improved method for interfacing a human user to the combination of an expert system and a computer aided design system, characterized in that the expert system advice is provided in various formats, the expert system provides for interrupted operation with usable intermediate advice, and expert system advice is transportable in relative correspondence into the computer aided design system schematic display environment.

Abstract: A circuit for regulating the output voltage of a switched mode power supply having a current mode magnetic amplifier includes a current transformer for sensing current flow through the magnetic amplifier. The sensed current is provided to a circuit which includes a resistor for developing a pulsating voltage and a storage capacitor for converting the pulsating voltage to a tracking voltage and storing the tracking voltage. The tracking voltage and a reference voltage are provided to a differential amplifier, the output of which operates a transistor which controls the operation of the magnetic amplifier, thereby regulating the output voltage of the power supply.

Abstract: A diameter gauge is disclosed for measuring the outside diameter of a part having a circular cross section. The gauge comprises two arms converging at right angles to one another within which the part is positioned for measurement.

Abstract: The subject invention is a device for joining and separating first and second printed circuit boards connectable by a socket on one of the boards and a plurality of pins projecting from the other of the boards. The device comprises a screw held captive to the first board but rotatable therein, and a spacer fastened to the second board and having a threaded hole for receiving the screw. The pins are inserted into and withdrawn from the socket by the engagement and disengagement, respectively, of the threaded hole by the screw.

Abstract: A switch mode power supply includes an AC to DC converter, a pulse width modulator for generating a series of pulses to control the switching of the DC across the primary winding of a transformer, and a start-up circuit connecting the AC to a power input of the pulse width modulator. A thermistor provides thermal protection for converter and start-up circuit components during abnormal operation, and a switch for disconnecting the start-up circuit and bypassing the thermistor after the power supply has been started improves power supply efficiency by eliminating power loss through the start-up circuit and thermistor.

Abstract: A circuit for the stable synchronization of an asynchronous data signal. The circuit comprises a first latch for receiving a first asynchronous data signal, a first delayed system clock signal, and a synchronized reset signal and for providing a system clock synchronized version of the first asynchronous data signal. A first delaying circuit receives a system clock signal and the first asynchronous data signal and provides the first delayed system clock signal. The circuit also includes a second latch for receiving a second asynchronous data signal which is a function of the inverse of the first asynchronous data signal and a second delayed system clock signal, and for providing the synchronized reset signal. A second delaying circuit receives the system clock signal and the first asynchronous data signal and provide the second delayed system clock signal.

Abstract: A non-contacting sensing method and apparatus is disclosed for positioning a surface, such as the surface of a workpiece. A collimated light beam is projected through a lens having a known focal length onto the surface. Suitable means such as a television camera is positioned to receive light reflected from the surface and provide a series of video pulses, wherein the number of pulses produced per television frame scan corresponds to the size of the light image focused onto the photosensitive element within the camera. The position of the surface relative to the lens is varied until the number of pulses produced per scan is at a minimum.

Abstract: A non-contacting sensing system for measuring dimensions or determining the position of an object, such as a workpiece in an automated machining process. A small diameter light beam is projected and focused at a predetermined location. A television camera, positioned to view the location, receives light reflected from the location and generates a video signal. This signal is provided to a circuit which detects changes in signal magnitude indicative of a change in position of the object relative to the predetermined location.

Abstract: This application deals with apparatus for calibrating an automated machining apparatus. The calibration apparatus comprises a tool probe and a system accuracy check gauge rigidly fixed to the workpiece loading mechanism of the machining apparatus. This arrangement allows variations in the locations of the cutting edges of the tools used in the machining apparatus to be taken into account in the machining operation and also allows checking of the dimensional and positional accuracy of the machining apparatus against a precisely known reference.