Remote supply circuit for AC loads in telephony - uses method of conjugate complex matching to design transformers between loads and four-wire line

摘要

The remote supply circuit feeds current to AC loads via a 4-wire telephone line and has transformers between the line and the load and between separate sections of line to compensate line losses. The transformers are designed using the method of conjugate complex matching. The loads are regarded as real impedances and are matched to the output impedance of the line (and the line sections matched one to another) using the relation R2 = R21 + X2, where R is the transformed input impedance of the load concerned, and Ri and X the complex output impedance of the line section.