| 摘要 |
<p>PURPOSE:To prevent malfunction caused by an external disturbing wave and to improve the S/J (signal/disturbing wave ratio) to the external disturbing wave by imposing frequency modulation upon a signal to be sent and passing a received signal through a matched filter suitable to the frequency modulation. CONSTITUTION:A reference signal generator 13 generates a reference signal with an intermediate frequency (IF) band and a dispersible filter 14 imposes the frequency modulation so that the frequency of the output signal of the generator 13 varies with time and also sends the modulated signal as a sent signal. The reflected signal from a target airframe is inputted through an antenna 1 and converted into an IF signal, which is amplified by an IF amplifier 17. The amplified signal is detected by a detector 18. The matched filter 20 has characteristics suitable to the frequency modulation and performs the pulse width compression of the output signal of the amplifier 17, and its output is detected by a detector 21. Then the pulse widths of the signals detected by the detectors 18 and 21 are prescribed pulse widths respectively and only when the amplitudes exceed a prescribed level, an initiation device is put in operation.</p> |
