BLER monitoring measures block error ratio, meaning how many forward error correction (FEC) codeword blocks contain errors.

In high-speed transceiver testing, BLER monitoring helps engineers understand how errors behave at the FEC block level. This is important because a link may show an acceptable average bit error ratio (BER), while still producing error patterns that place stress on FEC.

For 1.6T transceivers, BLER monitoring gives validation teams a clearer view of receiver performance, FEC margin, burst errors, and overall link stability.

For more detailed information on this methodology, read our white paper “Receiver performance verification method based on error mask and block error ratio (BLER)”.