A novel method of locating and tracking unknown signal by VNA

Vector Network Analyzer (VNA) uses its sources to generate a known signal, and then measure the stimulated response of the device under test (DUT). But In some circumstances, VNA needs to “recognize” the input signal first, and then use this signal to measure the relative response of the DUT. Using VNA's frequency offset mode, the image rejection method and the characteristics of VNA's digital IF board, VNA can recognize an unknown signal quickly and precisely.