Abstract: A method for determining an accurate vehicle speed, based upon the wheel speed data, for vehicle antilock systems in which the integrity of each individual wheel speed value is verified before including that wheel speed value in the reference speed calculation. Reference speed is then computed as a function of only those wheel speed values which have been successfully accepted into the calculation.

Abstract: A radar doppler frequency measuring system is described which times the duration between zero level cross-over of a selected number of doppler cycles. Errors due to spurious zero level cross-overs of the doppler signal due to noise is minimized by a circuit which imposes a time delay after the detection of a zero cross-over before the detection of the next zero cross-over. The time delay is made proportional to the period of the doppler signal to enable the system to operate over a wide doppler frequency bandwidth.

Abstract: A diplex doppler radar is described which includes an RF generator which generates an RF signal alternating between two selected frequencies. The RF signals are selectively vertically or horizontally polarized and transmitted by an antenna. A circuit is responsive to the received colinear and cross-polarized RF signals reflected from an object and provides an output representing the sum of the ratios of the colinear vertically polarized received signal to the colinear horizontally polarized received signal, the colinear vertically polarized received signal to the cross-polarized received signal, and the colinear horizontally polarized received signal to the cross-polarized received signal. The derivative of the sum of the ratios is divided by a signal representing the range rate of change between the obstacle and the radar system to generate a resulting signal which provides information relating to target identification and discrimination.

Abstract: A closed loop fuel control system for an internal combustion engine having a catalytic converter in its exhaust system and a pair of zirconia sensors for generating respective signals indicative of the air-fuel ratio in the gases upstream and downstream of the catalytic converter. These sensors are used in the control system to control the rate of flow of fuel or air to the engine in response to the sensor signals to maintain a constant stoichiometric air-fuel ratio in the exhaust system for maximum catalytic converter efficiency in simultaneous oxidation and reduction. A circuit is described for imposing the output of the zirconia sensor upstream from the catalytic converter across the zirconia sensor downstream of the catalytic converter until the zirconia sensor downstream of the catalytic converter reaches its operating temperature.