US Patent 7486114 Signal detector with calibration circuit arrangement

A signal detector and method to detect the presence or absence of an incoming differential signal. The method nullifies the DC off-set of the signal detector so that it can detect a signal within a very narrow window. The common mode levels of the signal and reference paths are used for calibration which is done automatically by use of an embedded algorithm residing in a digital block. The calibration range and resolution are predetermined to cope with the technology, modeling, design methodology and human error.