| 摘要 |
935,078. Radar; aerials. ALGEMENE NEDERLANDSE RADIO UNIE N.V. Dec. 29, 1959 [Jan. 5, 1959], No. 44108/59. Class 40 (7). A radar system comprises a broadside array of spaced aerial elements coupled to spaced points on a non-resonant transmission line or waveguide which is coupled to a transmitter generating a noise spectrum so that each frequency component is radiated in a different direction and the echo signal from a target in a particular direction as received by the same aerial system or by a separate similar aerial system comprises a narrow band of frequencies, Fig. 5 (not shown), whose mean frequency is characteristic of the direction; the mean frequency being determined by manual or automatic adjustment of a tunable " direction " filter having a pass-band narrower than the noise spectrum generated by the transmitter. The target range is determined by applying another output from the transmitter to a delay line through a filter having the same frequency characteristic as the output from the " direction " filter and adjusting the delay line (manually or automatically) to provide maximum correlation between the output from the delay line and the echo signal. The radial and tangential speeds of the target will be given by the rates of adjustment of the delay line and " direction " filters respectively. Aerial system.-The aerial array may comprise (1), Fig. 1 (not shown), a collinear array of dipoles fed from a transmission line; (2), Fig. 2, a staggered array of slots in a straight waveguide 4 terminated by a resistive wedge 5 or (3), Fig. 3, an array of slots 6 in a folded waveguide 4. In the Fig. 3 arrangement the electrical spacing between the elements is greater than the physical spacing so that a given sector can be covered with a smaller band of noise. |
