US Patent 7295087 Signal transmission circuit

A signal transmission circuit having a characteristic impedance includes a common mode filter, a first capacitive element, a first connection line, a second capacitive element and a second connection line. The first capacitive element has a first terminal. The first connection line connects one output of the common mode filter to the first capacitive element. The second connection line connects the other output of the common mode filter to the second capacitive element. The first connection line has a first length. The second connection line has a second length. Each of the first length and the second length is within a predetermined range to change the characteristic impedance.