Abstract: A vehicle communications network is provided which includes a ground translation circuit and interfacing transmitter circuits that achieve smooth current sourcing transitions. Included is a communications bus such as a J1850 having multiple-access for interfacing with a plurality of electronics, preferably within a vehicle. Each transceiver has a transmitter and receiver interfaced with the bus. The transceiver is coupled via a resistive element to the communications bus and sources current onto the bus when the transmitter output voltage exceeds the bus voltage. The added resistance advantageously reduces changes in current which may otherwise exist on the communications bus when current sourcing switches on and off.

Abstract: A vehicle communications network is provided which includes a ground translation circuit and interfacing transmitter circuits that achieve smooth current sourcing transitions. Included is a communications bus such as a J1850 having multiple-access for interfacing with a plurality of electronics, preferably within a vehicle. Each transceiver has a transmitter and receiver interfaced with the bus. The transceiver is coupled via a resistive element to the communications bus and sources current onto the bus when the transmitter output voltage exceeds the bus voltage. The added resistance advantageously reduces changes in current which may otherwise exist on the communications bus when current sourcing switches on and off.

Abstract: A link apparatus in a node of a multinode, collision-resolution, multiplexing communications system connected between a microcontroller (MCU) that receives measurand data from an input device such as a sensor and an integrated driver and receiver (IDR) for assuming some of the functions of the MCU in delivering and receiving messages to and from a single-wire bus communications network. The MCU contains firmware for converting the measurand data into data bytes, the link apparatus and the MCU contain circuits for effecting a SPI transfer and the link apparatus contains additional circuits for converting each bit of the message bytes into variable pulse width modulated (VPWM) bits. The VPWM bits get converted into J1850 symbols before being placed on a single- wire communications bus. Circuits are provided in the link apparatus for checking arbitration of the protocol and data symbols communicated over the bus.

Abstract: A ground translation circuit in a transmitter of a transceiver of a data transmission network for transferring symbol information contained in analog pulses from circuits referenced to logic signal power to circuits referenced to an independent DC voltage ground return for transmission over a bus. Complementary ground translation circuits in a receiver of the transceiver for transferring the analog pulses referenced with respect to the independent DC ground return back to circuits referenced to logic signal power.

Abstract: A transceiver device for use with a microcontroller and a symbol encoder decoder device (forming a node in a communications network) for transmitting and receiving variable pulse width modulated (VPWM) analog signals containing symbol messages over a communications bus. The transceiver accepts digital VPWM signals from the symbol encoder decoder device which were generated by the microcontroller and converts the digital signals into VPWM analog signals and then transmits the analog signal over the bus to other nodes. The transceiver also receives VPWM analog signals placed on the bus by other nodes of the network and transfers the signals in digital form to the symbol encoder decoder device which, in turn, communicates the decoded messages to the microcontroller. The transceiver contains a ground translation circuit for transferring transmitted signals to an independent bus ground return before a bus driver circuit sources message signals in the form of pulse currents over the bus.

Abstract: A transceiver device for use with a microcontroller and a symbol encoder decoder device (forming a node in a communications network) for transmitting and receiving variable pulse width modulated (VPWM) analog signals containing symbol messages over a communications bus. The transceiver accepts digital VPWM signals from the symbol encoder decoder device which were generated by the microcontroller and converts the digital signals into VPWM analog signals and then transmits the analog signal over the bus to other nodes. The transceiver also receives VPWM analog signals placed on the bus by other nodes of the network and transfers the signals in digital form to the symbol encoder decoder device which, in turn, communicates the decoded messages to the microcontroller.

Abstract: An electroluminescent display drive circuit which compensates for the decrease in capacitance of the electroluminescent display panel that is experienced as the panel ages; this is accomplished by use of an RC time constant which will effectively increase the voltage presented across the electroluminescent display panel as the capacitive element of the RC time constant decreases with the age of the panel. Also presented is high frequency power supply to excite electroluminescent displays without a transformer such that the voltage across the display is in phase with the current through the display thereby reducing the effect of power factor and electromagnetic interference.

Abstract: A calibration sequence and method for use with an electronic compass which allows for the separation of the vehicle's magnetic field from the earth's magnetic field so that the earth's field can be measured and used to give vehicle direction; such calibration sequence being done with a mirrored 180 degree re-orientation of the vehicle.

Abstract: Multiplexing a bandpass filter circuit to work with a flux-gate sensor output to minimize the amount of electronic circuitry required to work with the control system and to reduce the effect of gain on the circuit by emphasizing repeatability.

Abstract: A technique is provided to combine software and hardware; the hardware being used to place voltage levels into narrow ranges and the software being used to perform the precise calibration.

Abstract: A device to control a temperature variable-resistive type oil fluid level sensor in vehicles. The device employs constant current excitation under control of a relay to maximize the sensor's response and employs a shut-off feature to protect the sensor from overheating.

Abstract: A lamp failure indicating circuit particularly useful for automotive vehicle application such as detecting failure of headlamps, stop lamps and/or turn signal lamps. The disclosed circuit embodiments monitor branch circuits each containing a lamp load and comprising an associated transformer. Each transformer comprises two coils disposed on a ferromagnetic torroidal core. One coil of each transformer is connected in the branch circuit of the associated lamp load, the coil and lamp load being in series, and being associated with a means which forms therewith a complete circuit path which is independent of the power supply which energizes the lamp load. The other coils of the transformers are connected in a circuit to which a test signal is applied with the result of the test indicating whether any of the lamps are failed.