| 摘要 |
<p>PURPOSE:To detect the presence of an interference wave with high resolving power by detecting the amplitude difference between the phase difference signal of a transmission signal and the receiving signal being the reflected wave thereof and the delay signal thereof. CONSTITUTION:The receiving signal of a receiving circuit 1 and the self-transmission signal received by a receiving circuit 2 are inputted to a phase difference detection circuit 3 and a video signal having amplitude proportional to position difference is outputted. If the receiving signal is the reflected wave of a transmission radio wave emitted by self, the phase difference between both signals is constant and, therefore, the output amplitude thereof becomes constant. When the signal received by the circuit 1 is an emission signal other than self, since frequency is slightly different in usual, the phase difference is changed with the elapse of time and output amplitude changes. Therefore, the amplitude difference is compared with a delayed signal by a differential amplifying circuit 5 and, when the output is 0, an interference wave is judged to be absent by an interference judging circuit 6 and, when the output does not become 0, the interference wave is judged to be present. By this method, the restriction of resolving power due to the expanse of a frequency spectrum based on pulse modulation is not received.</p> |
