Intermodulation measurement using a microcomputer

An intermodulation distortion measurement technique using a microcomputer is studied. This approach is based on the theory deduced via a stochastic method instead of a series technique; it is also useful for nonlinear amplifiers that do not have smooth characteristics, such as a piecewise-linear limiter, a class-C amplifier, an A-D converter, etc.... This technique also allows to measure the intermodulation of amplifiers whose characteristics are temperature dependent. Measurement errors associated with the A-D conversion in the equipment are also discussed and the accuracy of this method is confirmed experimentally by using a UHF transistor amplifier.