ABSTRACT: 5G satellite communications networks utilize time division duplex (TDD) to optimize spectrum management, where uplink and downlink signals rapidly switch between different time slots on the same frequency band. Uplink/downlink handover requirements become tighter and tighter as applications move up in frequency. Test instruments need to be able to characterize the behavior of high-speed 5G TDD switches and measure network latency to avoid uplink/downlink overlap, interference, and a deterioration in performance.