US Patent 7743288 Built-in at-speed bit error ratio tester

A built-in, at-speed BERT is provided that may be part of high-speed serial interface circuitry implemented on an integrated circuit. The built-in, at-speed BERT takes advantage of an existing clock data recovery (CDR) dual-loop architecture and built-in self test (BIST) circuitry. The built-in, at-speed BERT provides a low-cost solution for production testing of high-speed serial links, facilitating jitter analysis and evaluation of pre-emphasis and equalization performance. This further allows adaptation of pre-emphasis and equalization.