Patent ID: 8115505

Claim:
A differential signaling system comprising: a differential signal line having a first wiring and a second wiring coupled between a sending end and a receiving end of the system; a termination resistor coupled between the first wiring and the second wiring in the receiving end side of the system; and a test circuit directly coupled to the termination resistor in parallel and configured to amplify and detect a variation of a differential impedance due to the differential signal line, wherein the test circuit includes: a differential test amplifier configured to amplify the variation in the differential impedance of the first wiring or the second wiring and output an output signal through an output terminal, a switching unit installed at an input terminal of the differential test amplifier and configured to control an operation of the differential test amplifier, and a peak detector coupled to the output terminal of the differential test amplifier and configured to convert the output signal of the differential test amplifier into a direct current component.