GB623354A - Improvements in or relating to electric or electromagnetic transmission networks or bridges - Google Patents

Abstract

623,354. Electric tests. SPERRY GYROSCOPE CO., Inc. Oct. 23, 1942, No. 14939. Convention date, Jan. 28, 1941. [Class 37] [Also in Groups XXXIX, XL (b) and XL (c)] A circuit analogous to the bridge type particularly for use at very high frequencies comprises four transmission lines 1 ... 4 connected in tandem to form a closed loop with lumped impedances Z1 ... Z4 between adjacent pairs. The transmission lines may take the form of shielded or unshielded twowire lines, coaxial lines, wave-guides or lumpedimpedance artificial lines, while one or more of the impedances Z1 ... Z4 may include a generator. If Z1 is a generator and Z3 an indicator or meter, and the four lines have similar characteristics, no current flows in Z3 when Z1 and Z3 are oppositely connected, that is to say, one in series and the other in shunt as shown in Figs. 4, 5. Such arrangements are suitable for making impedance measurements by a null method, Z2 and Z4 being unknown, and standard impedances respectively. Z2 and Z4 need not be simple shunt or series elements, as in Figs. 2, 3, but may be of more complex form, as shown, for example, in Figs. 6, 7. Fig. 8 shows a coaxial line construction in which the generator Z1 is arranged as a shunt element and the indicator Z3 as a series element. The Specification as open to inspection under Sect. 91 contains the following subject-matter: By the introduction into one of the bridge arms of a phase change of 180 degrees, e.g. by a transposition, Fig. 3 (Cancelled), or by a length of transmission line, Z1, and Z3 may be connected both in shunt or both in series thus, Fig. 13 (Cancelled), shows a hollow-pipe construction in which Z1, Z3 are both shunt elements and which includes a phase-shifting device 15 such as a line an odd number of wavelengths long. In another hollow-pipe construction, Fig. 14 (Cancelled), Z1, Z3 are series elements and the pipes 2, 3 are terminated by impedances 20, 201. This subject-matter does not appear in the Specification as accepted.