Patent ID: 6978328

Claim:
A bus system for carrying out data transfer between one bus master and a plurality of bus slaves, comprising: directional couplers are formed by arranging respective parts of lines drawn from said bus slaves, without being in contact with, in the neighborhood of, and in parallel with a line drawn from the bus master, wherein said line drawn from said bus master to a terminating resistance is wired being folded, wherein said directional couplers are formed by arranging said parts of the lines drawn from said bus slaves one after another alternatively with respect to a first line part of the line drawn from the bus master ranging from the bus master to a fold of said line drawn from the bus master and with respect to a second line part of the line drawn from the bus master ranging from the fold to the terminating resistance wherein two lines are connected to each other to constitute a directional coupler that is formed by arranging said two lines, in the neighborhood of and in parallel with said line drawn from said bus master to the terminating resistance, in order to transmit data between said bus master and each of said bus slaves, wherein a line is arranged from said each of the bus slaves to a junction of said two lines, to form a T-shape, wherein both ends of said T-shape directional coupler on a side of said each of the bus slaves are terminated for impedance matching, and wherein two directional couplers each having a positive forward crosstalk coefficient are connected to each other in a T-shape, so that, in data transfer of an NRZ (Non-Return to Zero) signal from the bus master, the directional coupler closer to said bus master generates positive forward crosstalk, the directional coupler distant from said bus master generates positive backward crosstalk, and, said forward and backward crosstalks are superimposed to generate an RTZ (Return to Zero) signal having a sharp rise or fall in a bus slave.