基于宽带调制信号的无源互调测试研究

随着收发共用和数字调制技术（如BPSK、QPSK）在卫星通信中大量使用，原有的连续波（continous wave,CW）无源互调（passive intermodulation，PIM）测试系统存在验证不充分的问题。设计了宽带调制信号PIM测试方法改进了原有的测试系统，通过采用通道功率测试PIM，测试研究结果表明BPSK、QPSK数字调制无源互调量值均高于连续载波信号2~9dB，考虑到卫星运行可靠性，采用数字调制宽带工作模式改进原有测试系统后更接近实际工作方式，提高了地面验证可靠性。

Research on passive intermodulation based on broadband modulation signal

With the extensive use of transmitter-recevier sharing and digital modulation (BPSK,QPSK) technologies in satellite communication, there are insufficient verification problems in the original continuous wave (CW) and passive inter modulation (PIM) test system. In this paper, a broadband digital signal PIM test method was designed by using the channel power to test PIM. The test results show that digital modulation PIM values of both BPSK and QPSK signals are higher than the CW carriers by 2~9 dB. Considering the operational reliability of the satellite, the digital modulation working mode was adopted to improve the original test system and the new test is closer to the pracical work, which improves the reliability of ground verification.