Linearity Testing Techniques for Sideband Equipment

The linear rf amplifier is a vital segment of all sideband equipments and measurement of its degree of nonlinearity is therefore of paramount importance. The basis for using the two-tone method of measurement is described by showing the types of nonlinear distortion products generated by the different orders of transfer characteristic curvature. Measurements by noise loading are described and it is shown that the results are essentially independent of the delay distortion characteristics of an amplifier. Descriptions of two basic types of distortion-measuring equipments, one using noise and the other using two tones, are given. Brief descriptions, photographs, and block diagrams are shown for audio-video and high-frequency spectrum measuring instruments.