Abstract: The speedometer is for use on a vehicle such as an automobile or train for providing a continuously updated digital reading of vehicle speed and a cumulative digital reading of total mileage traveled. By means of a front end transmitter-receiver antenna arrangement, a signal is provided, the frequency of which corresponds to velocity of the vehicle. This signal is coupled to a novel duty cycle detector which essentially rejects spurious noise signals and passes only signals of a predetermined duty cycle. A true signal is passed to a signal stabilization circuit which is responsive to the frequency of the signal for essentially replacing lost signal pulses. The pulse signal which is representative of vehicle speed is then coupled to both the odometer counter for ultimately providing a reading of mileage traveled and to the speedometer counter for ultimately providing a reading of vehicle speed.

Abstract: A radar system mounted on a vehicle and having an RF signal transmitted preferably in a confined beam in front of the vehicle and reflected from obstacles in the path of the beam to be reflected back to the vehicle. The system includes an asymmetrical magic tee which receives both the transmitted and received signals and provides a pair of Doppler frequency signals whose relative phase relationship determines whether the signal is an opening or closing Doppler signal. The signal employs a diplex Doppler detection scheme for providing both range and rate data. Under an imminent collision situation the system provides control signals to power means for pulsating the brakes of the vehicle to thereby avoid a collision.