| 摘要 |
<p>PURPOSE:To enable accurate measurement of distance to an object to be measured regardless of the position of the object measured, far or close, by performing a distance measurement based on the propagation delay time or based on a Doppler signal according to the distance measured. CONSTITUTION:When a control signal Sc is at 1 level as a reflection body exists far off, an oscillation output So having the second frequency f2 is supplied from an oscillator 1 of a radar unit and radiated from an antenna 13 through a circulator 5. A reflected wave Ar is fed to a mixer 17 through a circulator 9 to output a distance signal Sa having the frequency of the difference between it and the locally oscillated signal Sx having the first frequency f1. Then, when the signal Sc is 0 as the reflection body is very close in the distance, a PIN switch 7 is set to the semi-conducting position and an oscillation output So having the first frequency f1 is radiated from the antenna 13. The mixer 17 outputs a Doppler signal Sb having the frequency f3 equivalent to the difference between the frequency f1+ or -f3 of the reflection signal subjected to a Doppler shift and the frequency f1.</p> |
