Interfering Responses in Superheterodynes

Superheterodyne receivers respond to other frequencies than the one for which the receiver is tuned. Various types of these undesired responses are treated in particular with one type not generally recognized, the resultant of an offresonance signal combining with the receiver's oscillator and forming a signal, at the converter tube plate, which lies in thle vicinitiy of the intermediate frequency. High harmonic orders of this are present across the converter plate circuit which recombine, by plate modulation, in the internal plate circuit with the oscillator and form a signal at the intermediate frequency. Methods of reducing this effect are given.