Abstract

The measurement quality of a software defined radio system was investigated and discussed for medical diagnostics in the frequency band of interest 500 MHz–2 GHz. A calibration approach was proposed in order to deal with the random phase problem, and the obtained performance was evaluated and benchmarked against a vector network analyser. The results suggest that the measurement quality of the software defined radio system is mainly limited by the signal leakage from the transmitter to the receiver. Good agreement between the measurement data obtained with the software defined ratio system and the network analyser was achieved when the transmission loss is less than 70 dB. With some a priori knowledge of the measured object, the software defined radio system is able to perform accurate measurement when the transmission loss is even higher.