Abstract: A motion sensor system for a tire pressure monitoring system (TPMS) that uses a piezoelectric sensor to sense vibration as an indication of wheel motion. The TPMS uses the detected vibration to transition between operation modes. In one embodiment, the TPMS has a motion mode and a park mode, wherein the TPMS has increased activity (e.g. sampling tire pressure at a higher rate and transmitting tire pressure at a higher rate) during the motion mode than in the park mode.

Abstract: A test circuit for a motor vehicle cruise control system allows testing of the system without driving the vehicle. The cruise control system is of a type that has a vacuum servo for moving the throttle, solenoid valves for varying the vacuum in the servo, an electronic control module for controlling the solenoid valves, and a speed sensor that provides pulses to the control module corresponding to the actual vehicle speed. The test circuit is adapted to be connected between the control module and the leads extending to the various components of the system. The test circuit has series leads that connect the terminals of the system directly with the control module, except for the leads from the speed sensor. The test circuit has indicating means for determining whether or not voltage potential is present in the series leads to check continuity. An oscillator in the test circuit applies pulses to the control module that simulate pulses provided by the speed sensor.

Abstract: This invention relates to the use of a multiplexing technique to allow for the unambiguous enabling of remotely located receiving devices. In particular, a plurality of pushbutton switches, each capable of controlling a distinct function, has a common node whose output is transmitted through the single slip-ring usually found on the steering column of an automotive vehicle. This slip-ring is normally used to conduct an electrical voltage from the horn ring to the horn control relay independent of the position of the steering wheel. The multiplexing technique disclosed herein allows for separate and independent control of not only the horn but also other functions such as a cruise control using the existing single slip-ring as the mechanism to transmit the desired signal commands. The demultiplexed signals are derived from logic circuitry located at the distal point of the slip-ring assembly.

Abstract: An amplifier circuit is disclosed for temperature compensating the output voltage thereof with respect to undesirable temperature induced signals from a silicon pressure transducer and/or from components of the amplifier itself. The amplifier includes a first operational amplifier and a second operational amplifier. A first circuit connects the output terminal of the first operational amplifier through a summing node to one input terminal of the second amplifier. Output signals from the pressure transducer are applied between one input terminal of the first operational amplifier and another input terminal of the second amplifier. A temperature compensating circuit is connected to the summing node for enabling the output voltage of the amplifier to be substantially independent of temperature. An initial offset voltage compensating circuit is coupled to the summing node for adjusting the intercept of the pressure-to-output voltage transfer curve.

Abstract: A digital frequency quadrupler which provides output pulses at a rate equal to four times the number of input pulses. The input frequency range is extended by logic which allows additional pulses to be inserted in the output as the input frequency increases causing overlap between adjacent pulses. When the maximum upper range limit is reached the quadrupler saturates, that is, the output frequency becomes constant.