Response linearization of a diode detector type radio frequency electric field probe

An EPROM-based linearization circuit with a resolution of 0.1 percent of full scale has been designed to linearize the response of an orthogonal dipole electric field probe terminated with diodes. Design approach, performance, and probe characteristics are discussed. The nonlinear transducer response is first modeled with a fourth-order polynomial which fits the log-transformed calibration data. The equation is then evaluated at discrete points determined by the memory size and the A/D converter resolution. The antilog of the dependent variable is loaded into an EPROM memory for subsequent readout with a D/A converter and summing network. The response of other nonlinear transducers can be linearized by this method.