TRANSMISSION QUALITY MONITORING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To verify transmission quality between ATM(asynchronous transfer mode) processors at all times by using a simple counter and simple logic for the result of CRC(cyclic error control) checking. SOLUTION: A CRC checking part 301 uses both counter 303 for continuation for measuring the frequencies C1 of continuously detecting CRC errors and counter 306 for long time for measuring the member of CRC errors C2 in a prescribed cycle T and monitors that the frequencies C1 exceeds a predetermined stipulated value N1 for the counter 303 for the continuation and the number of errors C2 exceeds the predetermined stipulated value N2 for the counter 306 for the long time at all times. Then, cell synchronization is deeided and the transmission quality is verified at all times respectively for transmission quality degradation, nonstipulated intermittent errors, stipulated intermittent errors and a normal state.