| 摘要 |
<p>PURPOSE:To make it possible to discriminate the moving direction of an objective body, and to prevent a rear-end collision accident or a contact accident, by adding speed and direction discriminating function to the high frequency part of a simple CW Doppler radar. CONSTITUTION:The reflected waves egamma reflected from an objective vehicle 13 are received by an antenna 9 and respectively guided to mixer diodes 104, 105 through directionality couplers 101, 102. In the mixer diodes 104, 105, the reflected components and part of transmission waves are synthesized to be amplified by amplifiers 106, 107. When the transmission outputs IA, IB in the mixer diodes 104, 105 are set so as to be brought to the same phase and the distance of the directionality couplers 101, 102 is set so as to delay the phase egammaA of the received wave by pi/2 from egammaB, a Doppler beat signal is represented by a constant formula. When the objective vehicle 13 approaches to an automobile, IA is delayed by pi/2 from IB and, therefore, the approach of the objective vehicle 13 can be detected by monitoring this phase difference.</p> |
