Design considerations of transistorized broadcast receivers

摘要

The paper describes some design aspects of superheterodyne broadcast receivers employing germanium junction transistors, consideration being given only to circuits which are suitable for quantity production at economic cost. Particular attention is given to the effect of transistor spreads and component tolerances on receiver performance. The stages described include the frequency convertor, i.f. amplifiers, detector, a.f. driver and output stage. The frequency convertor considered is of the self-oscillating type employing a single transistor. I.F. amplifiers are discussed, with particular emphasis on the relative merits of band-pass and single-tuned couplings. In the treatment of detectors, consideration is given only to the type employing a point-contact germanium diode. The problems of overall instability due to stray magnetic couplings to the ferrite aerial are also discussed.