Improvements in or relating to electrical networks for producing pre-selected harmonics and sub-harmonics

摘要

867,611. Frequency changing. TELEFONAKTIEBOLAGET L. M. ERICSSON. Feb. 28, 1958 [March 20, 1957], No. 6621/58. Class 38 (2). A circuit for providing harmonics and subharmonics of the fundamental frequency (6 kc/s.) of an input signal comprises a series circuit L 1' C 1 across input terminals 1, 1SP1/SP and a circuit comprising an inductor L 2 , a load R 1 and a rectifier D across the inductor L 1 , the rectifier D possessing a large capacitance which varies with current flow. This rectifier may be germanium layer rectifier or the emitter-base part of a transistor. Subharmonic frequencies (3 kc(s.) are obtained across R 1 . Multiples of this subharmonic (9, 12, 15, 18 kc/s.) may be obtained across a load R 2 in parallel with the rectifier D, and when this is required the load R 1 may be made zero. A capacitor C 2 across the rectifier D is only an adjusting means for providing the required frequency spectrum and better stability. The resistive load R 1 may be replaced by a parallel resonant circuit tuned to the desired subharmonic.