Method for reducing crosstalk of analog crossbar switch by balancing inductive and capacitive coupling

摘要

A method for suppressing crosstalk in a telecommunications switching array is provided. The array includes a plurality of first transmission lines for accepting incoming signals, a plurality of second transmission lines for propagating outgoing signals, a plurality of switches, and a plurality of inductive couplings. The first transmission lines are arranged substantially in parallel to each other, and each of the first transmission lines has a characteristic impedance substantially equal to Z₀. The second transmission lines are arranged substantially perpendicularly to the first transmission lines so as to form an intersection between each of the first transmission lines and each of the second transmission lines, and each of the second transmission lines has a characteristic impedance substantially equal to Z₀. Each intersection includes one of the switches. Each of the switches is switchable between an ON state and an OFF state, and each of the switches has a characteristic parasitic capacitance substantially equal to C_m when in the OFF state. Each of the inductive couplings is associated with one of the switches, and each of the inductive couplings has a characteristic inductance substantially equal to L_m. The value of L_m is chosen so as to compensate for the parasitic capacitances such that suppression of crosstalk within the array is increased. The value of L_m may be chosen such that the equation L_m/C_m=Z₀² is satisfied. The choice of the value of L_m may be such that backwards coupling of the crosstalk occurs and the crosstalk is absorbed by a plurality of transmission line terminators. Each of the switches may have a characteristic series resistance substantially equal to R_on when in the ON state, thus causing a local impedance substantially equal to Z_local to be created at each of the plurality of switches when in the ON state. A value of R_on may be chosen such that a mismatch between the local impedance Z_local and the characteristic impedance Z₀ of each of the plurality of first and second transmission lines is reduced.