A New Frequency Transformer or Frequency Changer
I. Koga · Proceedings of the Institute of Radio Engineers · 1927
Alternating current having a frequency which is any fractional value of the frequency of a supplied current, can be obtained by means of a triode oscillator. The phenomenon seems to be due to the "attraction" of two nearly equal frequencies occurring in the triode circuit and to the non-linear characteristic of a triode.