Abstract: A two-wire communication system comprising a transmitting unit having constant current characteristics for controlling an output current thereof on the basis of a signal supplied from a sensor, a receiving unit for receiving a control signal to control the sensor, a load resistor and power supply connected in series with the transmitting unit via a two-wire transmission path, and a communication unit so connected in parallel to the load resistor as to convey the output current of the transmitting unit to the process side and control a current from the power supply transmitted onto the transmission path on the basis of information supplied from the process side.

Abstract: An excitation circuit wherein the energy of a charged coil is discharged via a sound generator. A coil and a capacitance of the sound generator are tuned to one another such that a corresponding oscillatory frequency is identical to a predetermined resonant frequency of the sound generator.

Abstract: A cursor control device (10) is provided which has a touch pad (14) formed of individual conductive plates (16) forming sectors of a circle. A user's touch on a dielectric layer (18) overlying the plates (16) is detected by individually charging and discharging each of the sector plates in a sequential manner to determine the increased capacitance, if any, of each sector plate. A microprocessor assigns each of the sector plates a relative X and Y weighting as a function of its angular position in the touch pad which are combined with the individual plate capacitance readings to calculate the relative X and Y position of the touch with respect to the origin (28) of the touch pad. Cursor control signals proportional to the relative X and Y values, plus a Z value proportional to the area of touch, if desired, are provided to the keyboard (12) of a displaying computer.

Abstract: The present invention is a simplified membrane keyboard employing a single flexible sheet. This membrane keyboard is employed in an electronic apparatus having an external case with a nonconducting keyboard surface. This nonconducting keyboard surface has a plurality of depressions corresponding to key switch positions. The keyboard surface is covered by a keyboard sheet. This keyboard sheet has a flexible membrane with opposed first and second surfaces, the first surface disposed adjacent to and substantially covering the keyboard surface of the external case. An interconnection pattern is placed upon the first surface of the flexible membrane. This interconnection pattern has a plurality of conductors and most particularly has a pair of conductors in proximity at each key switch position. Pressure applied to the second surface of the flexible membrane causes the flexible membrane to flex until the two conductors contact a conductive layer disposed in the bottom of the corresponding depression.

Abstract: A rail vehicle of a type for running on a pair of parallel rails has an apparatus for detecting the distance between it and a forward remote vehicle, for detecting the speed of the forward remote vehicle and for detecting discontinuities in the track. This is achieved by a first electrical contact for engaging one of the rails which applies a voltage between the contact and the first set of wheels of the vehicle which generate a short across the two rails. The spacing between the contact and the first set of wheels is such that a current runs from the contact forwardly of the vehicle to a short circuit across the rails generated by the next adjacent remote vehicle and back to a second electrical contact on the vehicle contacting the other rail. The magnitude of the voltage difference between the second contact and the first set of wheels is then measured to provide an indication of the distance between the vehicle and the next adjacent remote vehicle.

Abstract: An antilocking system is being proposed which does not generate unplanned control signals when axle oscillations occur. To this purpose, a threshold value stage 6 for the wheel deceleration signals (-b) has an increased threshold value. After separation of the wheel velocity V.sub.R from the vehicle reference velocity V.sub.ref, this value is again decreased in stages so that a normal controlled braking process is not affected.

Abstract: A fluid-sealed mounting comprises a base adapted to be secured to a vehicle body frame, for example, an attachment adapted to be connected to a source of vibrations, a first elastic member connected to the base and the attachment, a fluid chamber defined at least partly by the base, the attachment, and the first elastic member, and filled with a fluid, a partition dividing the fluid chamber into first and second chambers, and an orifice providing communication between the first and second chambers. The partition comprises a second elastic member connected to the base and the attachment. The rate of flow of the fluid through the orifice between the first and second chambers at the time the first elastic member is vibrated is different from the rate of flow of the fluid through the orifice between the first and second chambers at the time the second elastic member is vibrated.

Abstract: An automatic adjuster for a vehicle brake actuator has a non-rotatable brake shoe-engaging tappet, an adjuster member having a threaded shank threadedly engaged with a nut, the adjuster member co-acting with the tappet so that said rotation of the adjuster member causes axial movement of the tappet. The adjuster member is drivingly coupled by a coupling member to a shaft having an external reversible thread and a spring acting between the tappet and shaft urges the tappet against the shoe. A clutch ring has an internal reversible thread whereby it engages the corresponding thread on the shaft and is resiliently urged towards a fixed clutch face. The clutch ring controls rotation of the adjuster member during brake actuation and release to adjust the retracted position of the tappet to compensate for wear of the brake shoe.

Abstract: In railway signaling systems which transmit rate code signals along track circuits, which signals are picked up by the trains and used for signaling purposes, such as speed control, the rate code signals of the same repetition rate received when the train passes between adjacent track section may suffer a phase shift, also known as a phase jump. To prevent loss of the rate code signal during a phase jump, an improved rate code decoding system is provided wherein a correlation process is applied to the received rate code signal by multiplying the signal in separate multipliers with reference signals which are in quadrature and then cross-correlating the output of the multipliers with a step function and summing the absolute values of the outputs of the cross-correlators to provide a level which is substantially constant in the presence of a phase jump.

Abstract: A capacitance type displacement measuring instrument is disclosed in which a change in electric capacity between electrodes due to a change in displacement between two members movable relative to each other is detected on the basis of a change in phase of a detection signal and a displacement value between the two members is measured from the change in the capacity. AC signals are successively applied to transmitting electrodes provided on one of the members at a predetermined pitch by a multiplexer and signals induced in transfer electrodes at a predetermined pitch differing from the aforesaid pitch of the transmitting electrodes are received by pickup electrodes provided on the aforesaid one of the members. The relative displacement is detected from a change in phase of a received signal of substantially triangular waveform, which are obtained by the pickup electrode.

Abstract: A remote calibrated power source system comprises an instrument for generating power, the instrument being positioned at a first location, and a remote calibrated power source module for outputting calibrated power, the remote module being positioned at a second location that is removed from the first location. The remote module includes power sampling means for sampling the power generated by the instrument and generating a sampled voltage, the power sampling means having inherent frequency errors, a compensation circuit for generating a frequency-varying correction voltage, and summing amplifier means for receiving both the correction voltage and the sampled voltage and generating a compensated sampled voltage.

Abstract: An interactive data input device for a numerical control grinding machine is provided with a key board for inputting data which defines the shapes of a number of machining portions formed on a cylindrical workpiece and a central processing unit for controlling a display controller to display on a screen of a cathode ray tube (CRT) display unit the profile as taken along the workpiece axis, of each machining portion based upon the shape data input by the key board. The central processing unit is programmed to display, in addition to the profiles of the machining portions, the profile of a non-machining portion formed between two machining portions based upon the shape data for the two machining portions.

Abstract: A method for rapid windowing of display information in computer graphics is disclosed herein. Image display data is maintained in a hierarchical data tree structure. Small numbers of bits of data called summaries are maintained at the nodes of the tree. The large complete data image is divided into units called boxes. These boxes combine to form a master box for a particular window size. By searching the summaries for each box and locating the window within the master box, traversal of an entire subtree may be terminated quickly, proceed on only some of the subtrees, or proceed through to completion. A clipped image is rapidly generated that can be rendered to the viewer.

Abstract: A local data unit (10) provides sequenced acquisition and transmission of data signals received in different signal formats from local and remotely deployed sensors (24, 28). The network uses a microprocessor based stage (42) to sequentially control acquisition of the data signals via an analog multiplexer (16) and conversion of those data signals into a binary format via either a voltage-to-frequency converter (48) and frequency digitizer (58) or, after normalization, directly via the frequency digitizer (58). Data transmission in a normal mode is achieved by using the binary data signals to toggle input reference signals applied to multiplexer (16) between low and high potentials, and applying those potentials to voltage to frequency converter (48) while a data transmitter (52) is held in an enabled conditon.

Abstract: A charge redistribution capacitance detector is disclosed for detecting whether the capacitance of a variable capacitor is smaller or larger than that of a reference capacitor. First plates of the variable and reference capacitors are connected to a sense node, and a switching device responsive to a clock signal periodically impresses a reference voltage on the sense node during one phase of the clock signal and allows the sense node to electrically float during the alternate phase of the clock signal. Second plates of the sense and reference capacitors are alternately charged and discharged by equal voltage differences in opposite senses during successive clock phases. The voltage on the first plates of the capacitors changes in a sense dependent on the relative capacitance values of the capacitors and is compared with the reference voltage by a comparator which produces a corresponding detector output.

Abstract: Broken rail detection in a block of track without the need or expense of conventional signalling uses a chain of transmitters and receivers connected to the rails and defining sections of the block between the ends of the block. Either cyclically at a predetermined code rate or upon command of an external unit; an alternating current (AC) signal is launched from one end of the block and is repeated at different frequencies in each of the sections. When received at the end of the block, an indication of the absence of a broken rail condition is given either (a) by way of pole line or radio communication to a central control or dispatcher point and thence back to the trains, or (b) signals at the ends of the block are flashed at the code rate. The detected signal at the code rate may be used to modulate a direct current which is transmitted along the rails in the block to a signal at the opposite end of the block which also flashes at the code rate to indicate a safe condition.

Abstract: A method and circuit are disclosed for detecting the state of a variable capacitor by comparator means whose threshold voltage is impressed on first plates of the variable capacitor and a reference capacitor having a capacitance between the minimum and maximum capacitances of the variable capacitor, and charging and discharging the second plates of the variable and reference capacitors by equal amounts in opposite senses. The voltage on the first plates of the capacitors then changes in a sense dependent on the relative capacitance values of the capacitors and is compared with the threshold voltage by the comparator means.

Abstract: A coordinate position digitizing system to be used with a cathode ray tube, comprises a position determining plate having a plurality of conductors extending parallel with one another at regularly spaced intervals, and driving means for supplying a constant current selectively to the conductors, one after another, within a horizontal scanning period of the cathode ray tube. Magnetic flux detecting means detects magnetic flux on the position determining plate, and a band pass filter eliminates a noise component resulting from the deflection magnetic field of the cathode ray tube. Positional data defining a position of the magnetic flux detecting means on the position determining plate is produced in response to the output of the band pass filter.

Abstract: The present invention relates to a magnetic sensor apparatus (21) for use in a remote meter monitoring system (20) for remotely monitoring the dials (54a-e) of a utility meter (56) by use of Hall Effect devices (40-49). The Hall Effect devices (40-49) are concentrically positioned about the axis of rotation of a pointer member (64) having a permanent magnetic member (66) attached to a free end thereof. The Hall Effect devices (40-49) are axially displaced from the permanent magnetic member (66) and are in alignment with the circumferential path of travel of the permanent magnetic member (66). A microprocessor (68) electrically interconnected to the Hall Effect devices (40-49) selectively drives each of the Hall Effect devices (40-49). The microprocessor (68) further monitors the Hall Effect devices (40-49) and obtains output signals therefrom representative of the angular position of the pointer member (64).

Abstract: A compact keyboard for entry of alphanumeric data or other characters into a computerized system. A character formation key on the keyboard is formed by a plurality of bars which are capable of being activated for providing light. These bars are arranged in a mosaic pattern with several of the bars forming an outer box pattern and several of the bars extending inside of the box pattern. Light is emitted from each bar when such bar is in an activated lit condition. Each of the bars is switchable between an activated lit condition and an off condition, with the activated bars emitting light so as to display an alphanumeric character. The keyboard has a data entry mechanism for causing the displayed alphanumeric character to be entered into a computerized system.