| 摘要 |
1,213,028. Electromechanical delay lines; radar. COMPAGNIE FRANCAISE THOMSON HOUSTON - HOTCHKISS BRANDT. 11 July, 1968 [11 July, 1967], No. 33240/68. Headings H3U and H4D. A delay line intended to function as a radar echo simulator by producing a signal identical to that received from a moving target illuminated by a radar using the Doppler effect, comprises a piezo-electric transducer 1 having electrodes 2, 3 and mechanically coupled through a dielectric element 7 to a rod 4 of piezo-electric material. Electrodes 5, 6 at the rod ends enable a modulating signal S 2 to be applied to the rod. The input signal S 1 is applied to the electrodes 2, 3 through an input-output separator 8, an acoustic wave being propagated along the length of the rod 4, reflected from the remote end, and received back as a delayed output signal S 3 . The Doppler frequency shift is introduced by the modulating signal S 2 which applies a sawtooth waveform during the whole period of the input signal S 1 . The change in the rod length due to the signal S 2 causes the frequency to be shifted by an amount dependent on the slope of the sawtooth waveform. |
