A calibration system and method for a resistor ladder that employs relative measurement and adjustment between pairs of resistors. The system includes a resistor tree of complementary pairs of programmable resistors coupled to the resistor ladder, a measurement circuit that measures voltage differences...http://www.google.de/patents/US20030151532?utm_source=gb-gplus-sharePatent US20030151532 - CALIBRATION OF RESISTOR LADDER USING DIFFERENCE MEASUREMENT AND PARALLEL RESISTIVE CORRECTION
