Research And Implementation Of Reconfigurable Cni Rf Front End

As the rapid development of science and technology, the threats of air combatplatforms is also increasing, especially when the fourth-generation fighters equippedthe U.S. Air Force and the fifth-generation fighter is been researching. All this is afurther threat to country’s airspace security. All countries, in the world in, equippedcombat platform more and more electronic devices, for improving the superiorityduring the air battle. But all these devices have long been loosely piled up in theairplane. Not only does waste more power, occupy more room it, but also increasethe RCS (Radar Cross Section) and weak the plane’s mobility. In order to solve thiscontradiction, reconfigurable RF concept came into being.This paper first introduce the reconfigurable RF research profile in bothmilitary and civilian, including the “Pave Pillar” and “Pave Pace” project of theU.S. army. Then it introduces the software radio and digital radio and compares theiradvantage and disadvantage. On the analysis of the different RF front-end structure,it proposes a reconfigurable RF receiver front-end structure. Next, after researchingthe frequency characteristics of the communication, navigation and identification(CNI) system, it proposes the exact technical indicators of the front-end.The following content describes the principle and circuit implementation ofthe front-end, including RF filter group, IF filter group, mixer and AGC (AutomaticGain Control) circuit.The RF filters could switch the frequency freely between the frequency ofGPS navigation signals and IFF signals; IF filters could switch freely between fourbandwidths; The operation frequency range of mixer covers the GPS, IFF and JTIDSband; Also the Automatic Gain Circuit meet the requirements.Last using the modules, finished, and some other instrument, a simple CNIfront-end was built. After tested, the whole system’s operation frequency, bandwidth,dynamic range and some other indictor meet the design requirements.