| 摘要 |
798,055. Transistor negative impedance repeaters. STANDARD TELEPHONES & CABLES, Ltd. Nov. 23, 1956 [Nov. 29, 1955], No. 35879/56. Class 40 (6). A negative impedance repeater for a transmission line comprises two transistors of opposite conductivity type each having its output electrode cross connected through a D.C. path to an input electrode of the other to provide positive feedback, the line being coupled to one corresponding pair of the electrodes and an impedance network being coupled to another pair. In Fig. 1 the collectors of a P-N-P and an N-P-N transistor are cross connected to the bases while a transformer between the collector electrodes couples them to an impedance network N and a further transformer connected between the emitter electrodes has primary windings in series with each wire of a transmission line IE. The transistors are supplied from three batteries 63, 64, 65. In Fig. 2 the repeater is connected in series with the line by means of two transformers 23, 24 and coupling capacitors 21, 22, the terminal P being connected to terminal Q and terminal R to terminal S. The impedance network comprises resistors 28 and 29. In a further embodiment, Fig. 3 (not shown), in place of transformer winding 15c is coupled in shunt with the line and the impedance network is connected to a single secondary winding on transformer 11 while in Fig. 4 (not shown), an alternative shunt arrangement is used in which the line is connected to the collector electrodes through capacitors and the input terminals W, X and Y, Z are connected by chokes. The pairs of terminals P, Q and R, S are shorted and a resistance network in series with a coupling capacitor is connected between terminals P and S. In the circuits shown the transistors are of junction type. Specification 793,400 is referred to. |
