GB554675A - Improvements in or relating to frequency changing devices, more particularly for very short waves - Google Patents

Abstract

554,675. Valve receiving circuits. PHILIPS LAMPS, Ltd. (Naamlooze Vennootschap Philips' Gloeilampenfabrieken). March 13, 1942, No. 3350. [Classes 40 (iii) and 40 (v)] A frequency-changer particularly for ultrashort-waves comprises two diodes with the signal input fed in push-pull and the intermediate frequency -output taken in push-pull and having a common cathode with an oscillator, the common cathode circuit including an impedance. Fig. 1 shows an arrangement in which the input is fed through a Lecher wire system 9 and the output taken from the circuit 10. The oscillator is tuned by the Lecher wire system 7 and an inductance 8 is included in the lead to the cathode 2. The output circuit 10 is preferably connected to nodes in the Lecher wire system 9. In a modification a symmetrical tuned input circuit is used and the output is symmetrically arranged in parallel with a blocking condenser included therein, Fig. 2 (not shown). Alternatively with a Lecher wire input system the output may be taken through chokes from the diode anodes, Fig. 3 (not shown). Fig. 4 shows a similar circuit in which the output circuit 10 comprises cylindrical conductors which may be arranged in parallel or, as shown, may be concentrically arranged and the input taken through Lecher wire systems 9 and 24, 25 while the connection points 26, 27 are so chosen as to lie at a potential node for the signals and to offer maximum impedance in the resonator 10.