Method of modulating short and ultra-short waves for wireless signalling and the like

摘要

429,454. Microphones. ESAU, A., 15, Wilhelm Stadestrasse, and PFETSCHER, 0., 5A, Burgweg, both in Jena, Germany. Aug. 13, 1934, No. 23360. Convention date, Aug. 11, 1933. [Class 40 (iv)] [See also Group XL] Short radio waves are modulated by a microphone forming a leakage path across a high - frequency circuit such as a pair of Lecher wires. In Fig. 1, the Lecher wires 1, 2 have carbon rods 3, 4 inserted at a voltage anti-node which are bridged by a carbon lead 5 laid on them, the contact pressure being varied by impinging sound waves. Granules may be provided at the contact points. In Fig. 2, a transverse metal band 6 is slightly spaced from the Lecher wires 1, 2 the shunt capacity thus formed being varied by sound waves.