GB180349A - New or improved selective circuits for use in connection with alternating currents - Google Patents

Abstract

180,349. Potter, E., (Pernot, F. E. and Rich, L. J.). Nov. 18, 1920. Filter, rejector, and separator circuits.-In multiplex signalling systems &c., networks of impedances, such as those shown in Figs. 1 and 2, are utilized as units for enabling (i) the separation, in sequence, for subsequent utilization, of each component frequency of a complex current, and (ii) the combination of currents of different frequency. For example, by adjusting the values of the impedances in Fig. 1 so that for a given frequency Z1 Z4=Z2 Z3, the given frequency will not pass from the leads O, O<1> to the leads l, l<1>, whereas currents of all other frequencies will so pass. Similarly, by suitably adjusting the value of the mutual inductance between the coils L, L<1>, and the capacity C, in the arrangement shown in Fig. 2, any given frequency can be stopped without affecting the passage of other frequencies. Fig. 6 shows an arrangement of units A - - II, each similar to that shown in Figs. 1 or 2, for separating out the different frequencies f1 - - f4 of a complex current supplied at O, O<1>. The frequency f3 is eliminated by the unit A, and f4 at B, whilst the units C and D separate the remaining frequencies, f1 appearing solely at the terminals l, l<1>, and f2 solely at the terminals 2, 2<1>. Similarly, in passing through the branch E, F, G, H the frequencies are so acted upon that the frequency f3 appears solely at 3, 3<1>, and f, at 4, 4'. The arrangement may also be used to combine a number of separate currents of different frequencies into one complex current. Specification 178,873 is referred to.