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Balanced Electronic Hybrid Circuits with Line Matching Impedors

IP.com Disclosure Number: IPCOM000080383D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Fisk, DE: AUTHOR [+2]

Abstract

Except for line matching impedors 8 these hybrid circuit arrangements are readily fabricated by present day solid-state device techniques.

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Balanced Electronic Hybrid Circuits with Line Matching Impedors

Except for line matching impedors 8 these hybrid circuit arrangements are readily fabricated by present day solid-state device techniques.

A workable basic hybrid circuit is shown in Fig. A. A balanced two-wire transmission line 10 is represented by two lumped series impedance elements 12 and 14 and a voltage generating element
16. A voltage V(s) is presented at line terminals 20, 22 across a line impedance Z. This voltage is essentially amplified by an amplifier 26 of gain A(o) and the amplified voltage V is delivered at a local terminal 30, connected to a telephone receiver, for example. Any voltage V at a local terminal 32, coming from a telephone transmitter for example is amplified by an amplifier 34 for delivery to the line terminals 20, 22 when so desired. Resistors 36, 36, 38 and 38 are of relatively low value for generating voltages used in balancing the circuit, and isolating the amplifier 26 from the amplifier 34.

The impedor 8 is a discrete device connected across the line 10 at terminals 40, 42. It is capable of being adjusted to the exact line impedance in many applications. The output of the amplifier 34 is substantially prevented from reaching the amplifier 26 and the terminal 30, by the balancing resistors 36 and 38 and voltage dividing resistors 46 and 48, which are much greater in value than the resistors 36 and 38. The impedance of the output circuit of the amplifier 34 and the re...