Design And Realization Of Portable Transmitted PIM Test System Used In WCDMA System

With the development of high-power and multi-channel communication system, passive intermodulation interference has become one of the main factors which reduce performance of communication system. Passive intermodulation research plays a very important role in improving the quality of communication system. For the existing passive intermodulation test systems have many shortcomings, such as complex test operation, many test equipment and inconvenience for carrying, and this paper designs a portable passive intermodulation transmitted test system used in WCDMA system. The validation of the test system proves that the performance indexes meet the project expectations.Firstly, the characteristics of passive intermodulation and the impact in the mobile communication system are analyzed for the designed passive intermodulation transmitted test system, which provides a theoretical basis.Secondly, based on performance indexes and functional requirements of passive intermodulation test system, the overall designs of the test system are carried out. Through the expansion of test method recommended by IEC, automatic test and data analysis of the passive components in WCDMA communication equipment are realized.Thirdly, the detail designs for hardware and software of the passive intermodulation transmitted test system are carried out. Hardware components include test controlling unit, signal transmitting unit and signal receiving unit. The software mainly includes four modules: system parameters configuration, signal transmitting and receiving control, test results generation, remote network control.Finally, the experiments based on passive intermodulation transmitted test system are validated. The test results prove that the test system noise, residual intermodulation, test accuracy and other performance indexes meet the design requirements. The results show that: the system has good reliability and accuracy.