Method for pseudo-differential transmission using modal electrical variables

A device for transmission providing, in a known frequency band, m transmission channels each corresponding to a signal to be sent from the input of at least one transmitting circuit to the output of at least one receiving circuit, where m is an integer greater than or equal to 2, comprising:

• an interconnection having n transmission conductors and a return conductor distinct from a reference conductor, n being an integer greater than or equal to m, the interconnection being structurally combined with the reference conductor throughout the length of the interconnection, the interconnection being such that the interconnection can be modeled, in a part of the known frequency band, taking into account the lumped impedances seen by the interconnection and caused by the circuits connected to the interconnection elsewhere than at the ends of the interconnection, as a (n+1)-conductor multiconductor transmission line, the multiconductor transmission line having uniform electrical characteristics over its length, the multiconductor transmission line using natural voltages referenced to the return conductor and natural currents as natural electrical variables;
• at least one said transmitting circuit receiving m input signals of the transmitting circuit corresponding each to a transmission channel, the output of said at least one said transmitting circuit being coupled to the n transmission conductors, the output of said at least one said transmitting circuit delivering modal electrical variables when said at least one said transmitting circuit is in the activated state, the modal electrical variables being defined by a transition matrix from modal electrical variables to natural electrical variables of the (n+1)-conductor multiconductor transmission line, the transition matrix from modal electrical variables to natural electrical variables being non-diagonal, each of the modal electrical variables being mainly determined by one and only one of the input signals of the transmitting circuit;
• and
• at least one said receiving circuit delivering, when said at least one said receiving circuit is in the activated state, m output signals of the receiving circuit corresponding each to a transmission channel, the input of said at least one said receiving circuit being coupled to the n transmission conductors and to the return conductor, said at least one said receiving circuit combining the natural voltages referenced to the return conductor according to linear combinations, each of the output signals of the receiving circuit being mainly determined by one and only one of the modal electrical variables defined by the transition matrix from modal electrical variables to natural electrical variables.

A method for transmitting through an interconnection having n transmission conductors and a return conductor distinct from a reference conductor, n being an integer greater than or equal to 2, the method providing, in a known frequency band, m transmission channels each corresponding to a signal to be sent from the input of at least one transmitting circuit to the output of at least one receiving circuit, where m is an integer greater than or equal to 2 and less than or equal to n, the method comprising the steps of:

• numbering the transmission conductors from 1 to n and defining, for any integer j greater than or equal to 1 and less than or equal to n, at any given abscissa along the interconnection, a natural current of index j as the current flowing in the transmission conductor number j, and a natural voltage referenced to the return conductor of index j as the voltage between the transmission conductor number j and the return conductor;
• modeling the interconnection, in a part of the known frequency band, taking into account the lumped impedances seen by the interconnection and caused by the circuits connected to the interconnection elsewhere than at the ends of the interconnection, as a (n+1)-conductor multiconductor transmission line, the multiconductor transmission line having uniform electrical characteristics over its length, the multiconductor transmission line using the natural voltages referenced to the return conductor and the natural currents as natural electrical variables;
• determining, for the multiconductor transmission line and the known frequency band, a transition matrix from modal electrical variables to natural electrical variables, the transition matrix from modal electrical variables to natural electrical variables being non-diagonal in said part of the known frequency band;
• using one said transmitting circuit receiving m input signals of the transmitting circuit corresponding each to a transmission channel, the output of said transmitting circuit being coupled to the n transmission conductors, the output of said transmitting circuit delivering modal electrical variables defined by the transition matrix from modal electrical variables to natural electrical variables, each of the modal electrical variables being mainly determined by one and only one of the input signals of the transmitting circuit;
• and
• using one said receiving circuit delivering m output signals of the receiving circuit corresponding each to a transmission channel, the input of said receiving circuit being coupled to the n transmission conductors and to the return conductor, said receiving circuit combining the natural voltages referenced to the return conductor according to linear combinations, each of the output signals of the receiving circuit being mainly determined by one and only one of the modal electrical variables defined by the transition matrix from modal electrical variables to natural electrical variables.