Abstract: A circuit board has an arcuate array of conductor segments each subject to a digital waveform differing in phase for the various segments, and a concentric pickup conductor. A rotary encoder disk has a conductive pattern which sums and couples the waveforms from selected segments, depending on rotary position, to the pickup conductor. A synchronous phase detector generates a phase signal from the summed waveforms and the zero crossing of the phase signal is detected. A counter develops count signals used to generate the digital waveforms. The count signals are input to a latch which is clocked at the zero crossing point to latch the count value which is a digital measure of the encoder angle. Two encoders mounted on orthogonal horizontal axes are used as an accelerometer or attitude sensor. Each disk is eccentrically weighted to seek a position vertically below the axis to serve as an attitude sensor when the unit is stationary.

Abstract: An elastomeric connector couples the terminal pads of an LCD with corresponding terminal pads of a printed wiring board (PWB). Conductive elements in the connector are subject to skewing at such an angle that the LCD must be adjusted relative to the PWB to attain pad alignment. Sense pads on the terminal strips are coupled to contact pads and are arranged so that a continuity test on substantially opposed contact pads will verify pad alignment. In one embodiment, one sense pad is narrower than the terminal pads so that even marginal continuity will assure proper alignment of the terminal pads. In another embodiment, a pair of sense pads on either one of the LCD and the PWB is bracketed by a pair of spaced pads on the other such that continuity is evidence of non-alignment.

Abstract: Two or more communication modules are coupled by a one wire transmission line. A feed module impresses dc power and a sine wave carrier signal on the line. Each module generates a square wave signal synchronous with the carrier, each period of the signal representing one data bit. Data is written onto the line by a module by attenuating the carrier wave for selected bits and read by another module by sampling the bits and detecting those which are attenuated. Address and message data is transmitted in packets of n bits, the first bit always being an attenuated bit. Addressing is accomplished by generating a sequence of n unattenuated bits and then writing packets of address data. An address is valid when it matches a stored address in a module and that module is then activated to read or write.

Abstract: An input circuit for an automotive gauge driver receives a pulse width modulated or pulse frequency signal having a duty cycle representing a parameter to be displayed. A switching transistor controls an RC filter to develop an analog voltage proportional to the parameter. The input circuit biases the transistor to correctly respond to the input signal over a large range of supply voltage and where the ground potential differs from that of the source of the input signal. An output transistor means (or two) in series with a gauge coil (or two) is controlled by the analog voltage to provide coil current to effect linear gauge operation. Diodes in the input circuit limit the analog voltage range to end values which match the turn-on characteristics of the transistor means.

Abstract: An LCD display is backlit by a main light pipe with LEDs of a first color along one edge or opposed edges which uniformly flood the display with the first color, and with an LED of a second color coupled by a second light pipe to another edge to introduce light to local areas of the main light pipe. Filters of the second color over the local areas are illuminated by the second color LED. Prismatic sheets between the main light pipe and the LCD aid in the uniform distribution of the first color and improve display brightness by directing light toward the operator's eyebox.

Abstract: A rotary gauge driven by a stepper motor has a stop near the zero point of the gauge graphics. A factory calibration procedure rotates the gauge field in reverse direction to move the gauge pointer against the stop and continues field rotation until the rotor becomes unstable and flips back in the forward direction, and then moved to a rotor rest position. The angle of flip back, the rest position and the number of steps to the zero position are stored in non-volatile memory. In the vehicle, when the ignition is off, the microprocessor or the stepper motor wakes periodically and exercises the gauge, using the stored values to reset the gauge to the stable position. When ignition is turned on, the microprocessor moves the gauge directly to the zero position.

Abstract: An IC driver mounted on a LCD display package contains a sensor for determining temperature of the LCD cell, and a digital value of the temperature is serially transmitted to a remote microprocessor which determines compensated voltage and sends voltage command data back to the IC driver which produces a drive voltage by a charge pump. A digital code on the LCD cell identifies cell response characteristics and the code is used by the microprocessor to calculate the desired voltage. A ROM in the IC driver stores many bit-mapped images which are selected by the microprocessor for display.

Abstract: An apparatus includes a rotatably mounted magnetic rotor, a first coil mounted in proximity of the magnetic rotor, the first coil mounted such that, if the coil is flowing with electric current, the magnetic rotor is within immediate proximity of at least part of a magnetic field created by the coil. The apparatus includes a second coil mounted in proximity of the magnetic rotor, the second coil mounted such that, if the coil is flowing with electric current, the magnetic rotor is within immediate proximity of at least part of a magnetic field created by the coil. A current source is coupled to the first coil, for generating an AC signal and applying the AC signal across the first coil whereby an AC output signal develops across the second coil, the AC output signal having a magnitude that varies in relation to the rotational position of the rotor. A measuring circuit detects the AC output signal and develops therefrom a measure of the position of the rotor.

Abstract: The maximum full level is determined in a fuel tank of undetermined size using a fuel level sender referenced to the tank bottom. A minimum full value is selected for a given type of tank and when the sender signal goes below a percentage of that value and subsequently goes above the minimum full value, a fueling event is recognized and the current fuel sender value is adopted as the maximum full value. Where a heavily filtered signal is used to minimize the effects of fuel slosh, the maximum full value is subject to increasing to higher values occurring during a short period after fueling to allow recovery of the filtered signal. An empty value is calibrated before the vehicle is initially fueled. A maximum empty level is initially set and if a lower level is measured when the ignition is turned on, the lower level is set as the empty value. This calibration is terminated when the tank is fueled above the minimum full value.

Abstract: An apparatus for fuel level display systems comprises a fuel level sender providing a fuel level signal, a short period filter for filtering the fuel level signal through a short time constant filter, a long period filter for filtering the fuel level signal through a long time constant filter, a signal selector for selecting the long period filter output if the fuel level is above a trip point and for selecting the short period filter if the fuel level is below the trip point, and a display device for displaying a level of fuel in the tank in response to the selected signal.

Abstract: An apparatus for processing data, such as liquid level data in a motor vehicle containing a liquid storage tank, comprises a liquid level sensor for developing a signal indicative of instantaneous liquid level in the storage tank, circuitry for processing the instantaneous liquid level signal, including asymmetrical filtration of the instantaneous liquid level signal, to provide a process output signal, and a display apparatus for displaying an indication of the level of liquid in the storage tank in response to the process output signal.

Abstract: A circuit apparatus comprises interface circuitry between analog and digital circuitry. A multiple reference circuit provides a variety of reference voltage signals. The multiple reference circuitry is coupled to a selection circuit that selectively couples one of the reference voltage signals to a first reference input of the interface circuitry and selectively couples another of the reference voltage signals to a second reference input of the interface circuitry, whereby the first and second reference inputs may be selectively coupled to the reference voltages and the circuit maintains a ratiometric relationship between the digital and analog circuitry.

Abstract: A circuit apparatus for providing increased apparent resolution in digital signal processing systems includes a comparison circuit receiving an N bit digital input signal and the N most significant bits of an N+M bit output signal. The comparison circuit compares the two signals and provides a control output in response to the comparison. An N+M bit counter increases or decreases a count value which is the output signal in response to the comparison, whereby the output signal has an apparent resolution 2.sup.M better than the resolution of the input signal.

Abstract: An apparatus for applying a curve transfer function to an input signal comprises a first set of memory for storing values representing boundary points or distance differences along a curve of the transfer function, a second set of memory for storing slope values of lines connecting adjacent boundary points along the curve, a counter unit for maintaining a position count indicating position along the curve of the transfer function with respect to the stored boundary point values, an addressing unit, responsive to the position count, for selecting, from the second set of memory memory, the slope value corresponding to the position count, an accumulator for adding the selected slope value to an accumulator output value; and a comparator and data latch for determining when the accumulator output value corresponds to the input signal, and for selecting the corresponding accumulator output value as an output signal representing the application of the curve transfer function to the input signal.

Abstract: A circuit including a sender providing a sender output signal responsive to a vehicle parameter, circuitry for providing an adjustable reference, circuitry for comparing the output signal to the adjustable reference and providing a comparison output signal therefrom, an up/down counter for filtering the comparison output signal, and circuitry for providing an indicator control signal in response to the filtered output signal and for controlling the adjustment of the adjustable reference, provides a signal to a vehicle operator that is both filtered and has hysteresis to minimize repeated switching of the signal between two states.

Abstract: A circuit disclosed maintains ratiometric analog inputs to an integrated circuit using a network of resistors, some of which are external to the integrated circuit and some of which are internal to the integrated circuit, reducing expense. The analog inputs maintain a fixed ratio during fluctuations in supply voltage and fluctuations in temperature.

Abstract: An improved sender circuit which provides increased resolution measurements from a sensor by using two or more separately applied driving voltages. Only two connections to the sensor are required, the sensor having one or more switches closed in relation to the parameter being measured.

Abstract: A VF display control apparatus operated directly from an automotive storage battery in which the display brightness variation is minimized by controlling the relationship between the anode and grid voltages in relation to the fluctuation of the battery voltage. The anodes of the display are operated substantially at the battery voltage, and the grid voltage is reduced in relation to the amount by which the anode (supply) voltage exceeds the nominal open-circuit terminal voltage of the battery.

Abstract: A nonvolatile memory has a linear array of memory cells to serially store counts by setting the cells one by one in correspondence with input pulses and when the array is full by resetting the cells one by one for successive pulses. When all the cells are reset a conventional binary counter is incremented and the serial count is repeated for further inputs. This procedure minimizes the erase/write sequences required to count a series of pulses. A shift register having a stage corresponding to each memory cell is used to read out the data from the linear array. Data is loaded from the array into the shift register and shifted out in a serial pulse train to a binary counter.

Abstract: An electronic range indicator apparatus in which a switch array powered by the vehicle ignition voltage is used to indicate the selected transmission range during both on and off periods of the vehicle. During on periods of the vehicle, the ignition voltage is transmitted through the closed contacts (if any) of the switch array, and an electronic control module decodes the output of the switch array and lights the indicator indicia corresponding to the selected range. During off periods of the vehicle, the ignition feed to the switch array is open circuited. In such case, the control module intermittently reverses the potential across the switch array, and lights the appropriate indicator indicia using a reverse logic decode scheme.