To solve the problem wherein secondary common mode current is a noise factor in high-speed transmission by a differential transmission system of recent years.
This radiation noise suppression circuit for a differential transmission line includes: a differential transmission line which has plus line signal wiring 4a of a differential signal and minus line signal wiring 4b of the differential signal and connects a differential driver 1 and a differential receiver 2; signal GND wiring 5, one end of which is connected to the differential driver 1, and is wired outside along the differential transmission line; a coil unit 6 in which each of the plus line signal wiring 4a, the minus line signal wiring 4b, and said signal GND wiring 5 is wound in the same winding direction; a first impedance element 7a and a second impedance element 7b which have the same impedance value, and which are connected in series between the plus line signal wiring 4a and the minus line signal wiring 4b at a location nearer to the differential receiver 2 than the coil unit 6; and, a third impedance element 8, one end of which is connected to a junction point, where the first impedance element 7a and the second impedance element 7b are connected, and another end of which is connected to another end of the signal GND wiring 5.
FUSAYASU KOJI
TANIMOTO SHINICHI
MATSUBARA RYO
