Spectrum Analysis Of Non-linear Character Of The Ultra-shortwave Monitoring System

With the rapid development of the wireless communication, it isnecessary to ensure the efficient use of the radio frequency spectrum andthe proper operation of the various radio-communication services bystrengthening radio management and maintaining the order of radio wavesin the air.In order to strengthen the management, some kinds of technologies,such as adding the antenna gain and improving the sensitivity ofmonitoring system were used. But there was a problem that the non-linearcharacter of the device will greatly affect the sensitivity of the monitoringsystem.Non-linear character of the monitoring system is the sum ofnon-linear character of all part of monitoring system including wire,receiver, computer and amplifier.In this paper, a series of tests were designed to analyse the non-linearcharacter of the ultra-shortwave monitoring system by the spectrumanalysis. Through the tests some non-linear character of the monitoringsystem such as Third-order intercept point, phase noise, signal depressionand internally generated spurious responses will be observed clearly.Based on the test data, the sensitivity and the SFDR(spurious-free dynamicrange)also were calculated.Through these tests and calculation,we can notonly know the system well, but also use the system correctly.