US Patent 7952376 Method and apparatus for equalizer testing

Method and apparatus are disclosed related to testing and testability of adaptive equalization circuitry. Where an equalization circuit is provided in an IC, a modified internal loopback provides a testing signal. A local comparator circuit with flexible connectivity offers analog signal testing analysis in conjunction with a low-cost external tester. Flexible use and connectivity of the comparator and external connection points, and block isolation circuitry make accurate, faster, and lower cost testing methods possible.