| 摘要 |
<p>PURPOSE:To improve the utilization efficiency of a received wave by generating a rectangular sent wave and making the width and duty of a rectangular voltage correspond to the distance of a target. CONSTITUTION:A rectangular wave generation part 19 generates the rectangular voltage 20 based upon the signal of a signal processing part 13 and supplies it to one input terminal of an adder 12. Further, part of the output of a voltage-controlled oscillator 9 is converted through a directional coupler 8, frequency discriminator 10, and a low frequency amplifier 11 and inputted to the other input terminal of the adder 12, whose output is inputted to the control terminal of the oscillator 9, the output of which is a sent wave 21 indicating frequency variation synchronized with the voltage 20. Then a received wave 22 enters a mixer 3 through an antenna 1 and a circulator 2 and the mixer 3 mixes part of the sent wave with the received wave 22 and part of the rectangular wave 21 with the received wave 22 to generate the intermediate frequency 23 of the rectangular wave, whose frequency is equal to the width of frequency variation of the sent wave 21; and the width of the rectangle is equal to a time tR corresponding to the distance to the target. Further, the time tR is equal to the width of the voltage 20 and the duty of the voltage 20 is set to 50%, thereby increasing the utilization efficiency of the received wave 22.</p> |
