Compact cable balance network for echo-cancelling, and method for optimizing transhybrid loss and method and apparatus for circuit simulation

摘要

A cable balance network for use in a full-duplex telecommunication system and method for optimizing the transhybrid loss of a full-duplex to half-duplex conversion circuit, said cable balance network comprising: (a) a plurality n of resistors R_n, each of said resistors R_n having a fixed resistance value dependent upon the impedance seen by the full-duplex port, and each of said resistors R_n, having a positive node and a negative node; (b) a plurality n−1 of capacitors C_n−1, each of said capacitors C_n−1 having a fixed capacitance value dependent upon the impedance seen by said full-duplex port, and each of said capacitors C_n−1 having a positive node and a negative node; and (c) a circuit configuration comprising at least two of said resistors R₁, and R₂ (n≧2) and at least one of said capacitors C₁, such that all the negative nodes of each of said resistors R_n are effectively connected together, and such that the capacitor C_n−1is connected between the positive nodes of resistors R_n and R_n−1 for all values of n; the combination being constructed and arranged such that said circuit configuration, resistance values, and capacitance values define an optimized cable balance network input impedance and an optimized transhybrid loss for said conversion circuit. The invention is particularly useful in the design and simulation of telecommunication systems and echo cancelers.