| 摘要 |
<p>PURPOSE:To protect the detection capacity of radar from deteriorating due to the operational noise generated in a traveling wave tube (TNT) being employed at the transmitting section of a radar system and leaked to the receiving section. CONSTITUTION:The radar system comprises a receiving section 3 and a transmitting section 4 connected with a transmitting/receiving antenna ANT through a circulator 2, where the transmitting section 4 is provided with a TNT 5 having an outputted connected with an attenuator circuit 7 operable only when a signal is received. The attenuator circuit 7 comprises a lambda/4 transmission line 11 inserted into the output line of the TNT 5, first and second transmission lines 12, 13 comprising lambda/4+nlambda/2 (n is an arbitrary integer of 0, 1, 2... transmission lines 15, 17 connected, respectively, with the opposite ends of the line 11 and terminated with PIN diodes 16, 18, and a control circuit 14 for opening the PIN diodes 16, 18 at the time of reception in synchronism with the switching operation of transmission and reception.</p> |
