High Dynamic Range Measurement System

Equipment was acquired and fabricated that can be used to investigate RF distortion that occurs when an antenna is vibrating. The system is a single-channel transmitter that can drive a one-port device such as an antenna and then detect very small signals reflected or received from the port. Since some of the original transmitted signal appears with the received signal, the returned transmitted signal is cancelled so that small sidebands can be detected. In effect the signal transmitted is a radar signal and the sidebands on the returned radar signal are measured. The dynamic range achieved exceeds 150 dB when measured as the ratio of the smallest received signal that can be detected to the transmitted signal. The received signal can be a few hertz away from the 900 MHz transmitted signal.