| 摘要 |
<p>PURPOSE:To obtain a signal retransmission apparatus, which can guide the range tracking of radar smoothly without using a delay line, by shifting the frequency of the received signal of the chirp radar by a specified frequency, and retransmitting the signal. CONSTITUTION:The received signal of a chirp radar through a receiving antenna, e.g., the chirp signal (Figure a2) whose frequency is linearly shifted from fR by DELTAF with a width T (Figure a1) at a time t0 is inputted into a frequency shifting circuit 2. The frequency is shifted by an arbitrary preset value DELTAf. Then the signal is outputted (Figures a3 and a4). The output signal is transmitted through a transmitting antenna 3. The retransmitted signal is inputted into the pulse compressing circuit of the chirp radar. A delay time between the input and the output is linearly changed in this circuit [Figure (b): in the case of a frequency fR, the time tau is T; in the case of a frequency fR+DELTAF, the time tau is 0]. Therefore the timing relationship of the input and output signals in the pulse compressing circuit is shown in Figure (c), and the timing can be delayed by DELTAf/DELTAF.T. The value of DELTAf is continuously changed, and the range tracking of the radar can be smoothly guided.</p> |
