Investigation of the transmitter susceptibility to reverse intermodulation by the use of double-frequency diagrams

A technique for detection of reverse intermodulation components (which are generated if an external interfering signal received by the transmitting antenna influences on the output stages of the transmitter) by measuring the interference frequency response of the transmitter output spectrum and visualizing that response as a double-frequency diagram is developed. A technique for automated recognition (identification) of the reverse intermodulation types and orders on the basis of the double-frequency diagram is proposed. Both techniques are validated by the experiments. Amplitude responses for reverse intermodulation components of various types and orders are measured.