Patent ID: 7791429

Claim:
An equalizer using in a signal transmission line, the equalizer comprising: a first resistor; a capacitor comprising a positive terminal connected to the signal transmission line on a printed circuit board, and a negative terminal connected to ground through the first resistor; and a second resistor connected in parallel with the capacitor; wherein a resistance R 1 of the first resistor is calculated as follows: R ⁢ ⁢ 1 = R ⁢ ⁢ 2 * ( 1 - 10 A / 20 ) 10 A / 20 , A is a given low frequency gain, R 2 is a resistance of the second resistor; and a capacitance C 1 of the capacitor is calculated as follows: C ⁢ ⁢ 1 ≥ R ⁢ ⁢ 1 + R ⁢ ⁢ 2 2 ⁢ π ⁢ ⁢ FR ⁢ ⁢ 1 ⁢ R ⁢ ⁢ 2 , F is a main frequency of a signal transmitting through the signal transmission line.