Abstract: A drive circuit for a liquid crystal display includes a counter for each column of the display. The counters are set with brightness counts to establish the grey scales for the pixels. The counters turn transfer gates on when a count is present and off when the count is zero. An analog generator biases the columns through the transfer gates so that each column is biased to a level determined by the brightness count of the respective counter.

Abstract: For an oscilloscope capable of simultaneously displaying a plurality of waveforms on a screen and capable of performing operations with respect to a selected one of the displayed waveforms, a method and apparatus for permitting an operator to select a waveform. A touchscreen mechanism provides input signals to the oscilloscope indicating when and where an operator touches the surface of the screen and a microcomputer within the oscilloscope determines from data controlling the display of each waveform and from the data provided by the touchscreen whether the operator is touching any portion of a displayed waveform. If so, the microcomputer assumes that the operator has selected the waveform touched and reconfigures oscilloscope operation such that operations are performed with respect to the waveform touched by the operator.

Abstract: A pager has a receiver for receiving selective paging numbers and message data and a message display panel for displaying paging messages to the user. The pager has a first memory for storing message data. Control data, arriving together with the message data and related to its display, is stored in a second memory. A display controller, responsive to external operating inputs from the user, is provided for controlling the contents of the messages to be displayed on a basis of the control data. A display responds to control from the display controller, to read out and display messages stored in the first memory.

Abstract: An electronic sketching device. The electronic sketching device includes a display for providing a visual representation of a sketch on a display area. The electronic sketching device also including a cursor controller for moving a cursor on the display and a sketch controller for selectively storing the placement of the cursor on the display area as a pixel to create a sketch on the display area. A storage device, which is coupled to the sketch controller, stores a plurality of sketches. The electronic sketching device also contains a sketch memory for creating and storing a sequence of sketches which is coupled to the storage device. An animater, coupled to the storage device, sketch memory and the display, causes the stored sequence of sketches to be sequentially displayed on the display.

Abstract: A signal display element for the display of more than two informations by electromagnetically excited tilting plates supported in bearings on a baseplate (1) and containing magnetic parts and adapted to be rotated about an axis of rotation (3), wherein the magnetic axes of the parts of the tilting plates containing the magnets (5) run normal to the plane of the tilting plate, bipolarly excitable field coils are coupled to the tilting plate (4) for controlling the rotation thereof.

Abstract: On a circumferential side surface of a single cylindrical member constituting a main body of a rotor section are disposed, in parallel, a first pattern which repeats change in the circumferential direction with a predetermined pitch and a second pattern which has a change of one cycle with respect to one circumference. A detection head section which is provided in proximity to the rotor section changes its relation of correspondence to the respective patterns in accordance with rotational position of the rotor section and produces output signals corresponding to the relation of correspondence. A relatively rough absolute value of a rotational position within one rotation is established by an output signal produced in response to the second pattern and its accuracy is established with a high resolution by an output signal produced in response to the first pattern.

Abstract: An apparatus is provided for self-monitoring a communication circuit incorporating a differential driver for malfunctions with a malfunction detector located remote from the driver. The malfunction detector monitors the state of signals received at the remote location on a pair of lines coupled to the driver. Preferably, the detector includes a pair of back-to-back light emitting diodes, one of which will emit light so long as the received signals are in opposite states, and neither of which will emit light when the received signals are not in opposite states as will occur during a malfunction. The detector further preferably includes a phototransistor responsive to the diodes to provide a malfunction signal when neither diode emits light. Alternatively, the detector may comprise an exclusive-OR logic gate.

Abstract: A keyboard assembly has a PC board providing a series of switch contacts and a molded rubber keyboard providing a rubber base sheet overlying the PC board and having a series of rubber keys integral with the base sheet. Each key has contacts on its bottom surface for closing each of the switch contacts when its key is depressed. Stabilizing membranes prevent the keys from wobbling or binding. The membrane snugly engages each key, and the membrane is flexible along its Z axis but sufficiently stiff along its X and Y axes to limit the movement of the keys to strictly linear movement toward and away from their respective PC board switches.

Abstract: At transmission (10) each bit for transmission is coded as a function of its state by producing (12) a particular coding frequency combination, these being divided into two distinct bands spaced one from another and the coding combinations being chosen such that frequencies ranked in the same sequence place in these combinations do not occupy the same frequency band. A signal comprising the coding combination is injected to the network (N,P) and at reception (20), is applied to demodulators (22, 23), each assigned to one respective frequency band, to be correlated with locally generated signals (25, 26) which reproduce the coding combinations with a constant frequency shift, the bit state being determined (24) as a function of the correlation output.

Abstract: An input device for design work on image-bearing screens with which, by analogue-type hand movements which are identical in direction and magnitude with the requirements sought, graphics can be generated as in a conventional manner with a drafting head, and straight-edge and dividers.

Abstract: A buoy for marine vessels that is responsive to a transmitted RF signal of a set frequency consisting of an RF receiver disposed within the buoy and tuned to a set frequency of the transmitted RF signal and an antenna coupled to the input of the RF receiver. A switching circuit is coupled to the RF receiver, and a lamp is disposed on the buoy so that when the RF receiver receives a signal at the set frequency, it will operate said switching circuit and turn on said lamp. The buoy may be a pick-up buoy having an elongated stem on the top of the buoy, and containing the antenna. The lamp can also be mounted on the end of the antenna. A sound source coupled to the output of the switching circuit can sound an audible signal in response to the transmitted RF signal.

Abstract: A multi-wire data transmission cable for transmitting data signals over long distances between data devices. Presently, data devices are usually equipped with voltage interfaces for the connection of peripheral instruments. The length of data transmission lines connecting such devices is limited, due to line resistences. For transmission over long distances, signals must be converted prior to transmission and then must be reconverted after receipt of transmission. The present invention allows the connection of long transmission lines to data devices without the need of external signal converters or additional units normally required. The handle portion of the plug connection at either or both ends of the cable houses a circuit that incorporates a signal converter. No additional external units are required to connect data devices over long distances, since the converter is integrated into the cable.

Abstract: A switch/display unit comprises a dot matrix display, having two sets of elongate electrodes, one set being inclined to the other, these sets being applied to opposite sides of a display medium. A transparent dielectric panel is superimposed in front of the display, so that the first set of electrodes, which are formed from a transparent conductive material abut the rear surface of the dielectric panel. A transparent conductive layer is formed in front of the dielectric panel, so that it will capacitively couple electrodes of the first set of electrodes with other electrodes of the first set of electrodes or other electrodes on the rear surface of the dielectric panel. This capacitive coupling may be varied by touching or moving the conductive layer. By applying read pulses to one of the sets of electrodes that are capacitively coupled via the conductive coating and sensing the pulses transmitted to the other electrodes, actuation of the switch can be detected.

Abstract: A transmitter circuit adapted to be connected to a sensor and generate a 4-20 milliampere signal proportional to the output of the sensor includes a first amplifier which is connected to the sensor and has an output voltage proportional to the sensor output voltage. A predetermined reference voltage is supplied to a reference input of the first amplifier. A second amplifier housing an output voltage responsive to a difference between its input voltages, has its output connected to the gate of an output transistor, preferably a fluid offset transistor. An output resistor is connected between the positive power supply and the source of the output transistor. The output of the first amplifier is supplied to the positive input of the second amplifier and the voltage at the source of the output transistor is supplied to the negative input of the second amplifier. The output current for the transmitter is generated at the drain of the output transistor.

Abstract: An electronically controlled mechanical keyboard simulator includes a key selector switch and a signal generating circuit for outputting a preliminary symbol selection signal and a final symbol selection signal, and a keyboard interface circuit. The keyboard interface circuit has a row selector and a column selector, and a scanner for scanning the row and column selectors. The row selector has an enable input terminal which receives the preliminary symbol selection signal as an output disabling signal and the final symbol selection signal as an enabling signal for row identification of a selected information key and output of a row identification signal to the column selector. The column selector is operative upon receipt of the row determining signal for selecting an information column identifying output terminal and outputting the selected row information thereon to a microprocessor for data retrieval and communication of the selected information to the user by a display or audio device.

Abstract: A bi-directional, digital data transmission system is disclosed for transmitting an interrogation signal in a first direction from an interrogation unit to a data gathering transponder unit, and a data return signal in a second direction from the meter or data gathering transponder unit to the interrogation unit. This system comprises a single transformer having a primary winding coupled to the interrogation unit and a secondary winding coupled to the transponder unit. The interrogation unit generates an interrogation signal comprised of a first train of regularly occurring digital clock pulses and transmission interval pulses, each transmission interval pulse defining a transmission interval for the transmission of the data return signal. The transmission interval is set to be of a sufficient length to permit the transformer to desaturate to a level to permit efficient transmission of the data return signal to the interrogation unit.

Abstract: An indicating device mounted on a vehicle, provided with an operational circuit having a plurality of vehicle control modes for indicating both a control operational circuit such as the occurrence of a trouble. The selection of the vehicle control mode is effected by a selective switch and a mode selection signal is fed to a mode selection input terminal of the operational circuit. Indicating elements are connected to this mode selection input terminal to indicate the mode. Outputs from the operational circuit are fed to the indicating elements through the mode selection input terminals, whereby the indicating elements combinedly function as the mode indicator and the output indicator.

Abstract: A brake adjustment monitoring device of use on motor vehicles to warn the operators when the brakes are in need of adjustment or repair. A magnet is adjustably secured to the brake shaft connected to an existing brake air chamber assembly. A magnetically sensitive switch which is electrically connected to a wear signaling device is mounted on a rod proximate to the brake shaft at a predetermined distance from the magnet, so as to close the switch by magnetic flux when the shaft of the air chamber moves outward too far after the operator touches the brake pedal of the vehicle. The switch when closed energizes the wear signaling device, such as a buzzer and bulb, to alert the operator that the brakes are in need of adjustment.

Abstract: In a battery powered radio paging receiver, a battery saving method extends battery life and prevents the loss of messages stored in volatile random access memory. Upon receipt of a message, a plurality of alerting devices (vibrators, LCD back-lights, LED's and audio alert tone generators) are sequentially activated. Before each device is activated, however, the battery voltage is checked to determine if sufficient charge remains to power the alerting device without dropping the battery voltage below the minimum requirement for retaining information in the memory. If an alerting device is activated, the battery voltage is repeatedly checked and if it drops below a threshold level, the device is deactivated. If the alerting device is an escalating volume audio alert tone generator and the battery voltage is below a threshold voltage, the volume of the generator is restricted to its lower volume range. The received message is also checked to determine if it has a priority status.

Abstract: A device for the display of data, comprising on the one hand a matrix of luminous dots (11a, 11b, . . . 11n) each of which is constituted by at least one pair of light-emitting diodes arranged in anti-parallel with the color of the light emitted by one diode of the pair being different from that of the other diode, and comprising on the other hand, an electric a.c. voltage supply source (16) whose output terminals (17 and 18) can be coupled to the supply terminals of the luminous dots by electronic switches (25a, 25b . . . 25m) controlled by a control signal generator (30). A color variation requirement, referred to as "background" of the sign, is obtained by rendering the electronic switches (25a, 25b, . .