Graphical Presentation of Spurious Responses in Tunable Superheterodyne Receivers

The theory of intermodulation responses in superheterodyne receivers is briefly reviewed. The frequency bands of the responses are determined and factors affecting susceptibility levels as well as quantitative values for a typical crystal mixer input superheterodyne receiver are presented. On the basis of this groundwork, it is shown that the receiver's primary and spurious responses may be conveniently presented in graphical form. The graphical presentation can include the effects of input band-pass filters and tunable preselectors, and provides a grid upon which an electromagnetic environment may be superimposed.