Multichannel interfacing device having a termination circuit
The invention relates to an interfacing device for transmission through interconnections used for sending a plurality of electrical signals. The interfacing device of the invention comprises signal terminals and a common terminal. A receiving circuit delivers, when the receiving circuit is in the activated state, “output signals of the receiving circuit” determined each by a linear combination of the voltages between one of the signal terminals and the common terminal, to the destination. A termination circuit is such that, when it is in the activated state, it is approximately equivalent, for the signal terminals and the common terminal, to a (m+1)-terminal network such that, for small signals, the impedance matrix, with respect to the common terminal, of the (m+1)-terminal network is equal to a wanted non-diagonal matrix of size m×m.
1. A device for transmitting signals through a plurality of transmission channels, in a known frequency band, comprising:
m signal terminals, a common terminal and a reference terminal, the signal terminals being intended to be connected to an interconnection having m transmission conductors, m being an integer greater than or equal to 2;
a receiving circuit delivering, when the receiving circuit is in the activated state, p output signals of the receiving circuit corresponding each to a transmission channel, p being an integer greater than or equal to 2 and less than or equal to m, the input of the receiving circuit being coupled to at least p of the signal terminals and to the common terminal, each of the output signals of the receiving circuit being mainly determined by one or more of the voltages between one of the signal terminals and the common terminal; and
a termination circuit coupled to each of the signal terminals and to the common terminal, the termination circuit being, when the termination circuit is in the activated state, approximately equivalent, for the signal terminals and the common terminal, to a (m+1)-terminal network such that, at at least one quiescent operating point, for small signals in a part of the known frequency band, the impedance matrix, with respect to the common terminal, of said (m+1)-terminal network is equal to a wanted non-diagonal matrix of size m×m.
2. The device for transmitting signals of claim 1 , wherein each of the output signals of the receiving circuit is mainly determined by a linear combination of the voltages between one of the signal terminals and the common terminal.
3. The device for transmitting signals of claim 1 , wherein each of the output signals of the receiving circuit is determined by one and only one of the voltages between one of the signal terminals and the common terminal.
4. The device for transmitting signals of claim 1 , wherein the termination circuit is in the activated state when the receiving circuit is in the activated state.
5. The device for transmitting signals of claim 1 , wherein the impedance matrix, with respect to the common terminal, of the termination circuit in the activated state can be adjusted by electrical means.
6. The device for transmitting signals of claim 1 , wherein the termination circuit has an activated state and a deactivated state, each current flowing from the termination circuit to one of the signal terminals being substantially zero when the termination circuit is in the deactivated state.
7. The device for transmitting signals of claim 1 , further comprising a transmitting circuit receiving q input signals of the transmitting circuit corresponding each to a transmission channel, q being an integer greater than or equal to 2 and less than or equal to m, the output of the transmitting circuit delivering, when the transmitting circuit is in the activated state, at least q transmission variables to the signal terminals, each transmission variable being mainly determined by one or more of the input signals of the transmitting circuit.
8. The device for transmitting signals of claim 1 , wherein said device for transmitting signals constitutes a part of an integrated circuit, the interconnection being realized inside the integrated circuit.
9. The device for transmitting signals of claim 1 , wherein said device for transmitting signals constitutes a part of an integrated circuit, each of the signal terminals being coupled to one or more pins of the integrated circuit, the common terminal being coupled to one or more pins of the integrated circuit.
10. The device for transmitting signals of claim 1 , further comprising a damping circuit coupled to the common terminal, the damping circuit being, for the common terminal, approximately equivalent to a 2-terminal network consisting of a passive two-terminal circuit element connected in series with a voltage source delivering a constant voltage, the 2-terminal network having a first terminal connected to the common terminal, the 2-terminal network having a second terminal connected to the reference terminal.
11. A use of the device for transmitting signals of claim 1 , wherein the common terminal of the device for transmitting signals is grounded.