Method for pseudo-differential transmission using 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, the electrical characteristics being such that the propagation constants of the different propagation modes of the multiconductor transmission line are considered as substantially equal 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 at least m of the transmission conductors, the output of said transmitting circuit delivering natural electrical variables, each of the natural electrical variables being mainly determined by one and only one of the input signals of the transmitting circuit;
• 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 at least m of the transmission conductors and to the return conductor, each of the output signals of the receiving circuit being mainly determined by the natural voltages referenced to the return conductor;
• determining, for the multiconductor transmission line and said part of the known frequency band, a characteristic impedance matrix with respect to the return conductor;
• and
• coupling the terminals of at least one termination circuit to the return conductor and to each of the transmission conductors, said at least one termination circuit being, in said part of the known frequency band, approximately characterized, for the interconnection, by an impedance matrix with respect to the return conductor, the impedance matrix with respect to the return conductor being a non-diagonal matrix of size n×n approximately equal to the characteristic impedance matrix with respect to the return conductor.