Error rate measurement apparatus and error rate measurement method

An error rate measurement method using an operation unit that performs a setting, and an error detector that receives a pulse amplitude modulation 4 (PAM4) signal based on bit string data of a pseudo random bit sequence (PRBS) pattern transmitted from a device under test and that detects an error, wherein

• in a step of performing the setting by the operation unit, a Flit length according to the number of lanes defined in a high-speed bus standard, a mask pattern length for masking a portion corresponding to a skip ordered set (SKP OS), a mask pattern period corresponding to a repetition period of the SKP OS, and a threshold value for determining a Flit error are set, and
• the error rate measurement method comprises:
• a step of, by a symbol mask generation unit of the error detector, generating a mask pattern based on the mask pattern length and the mask pattern period;
• a step of, by an error detection unit of the error detector, detecting and counting an error in a portion corresponding to Flit by dividing the PAM4 signal received from the device under test by intervals of the Flit length and masking the portion corresponding to the SKP OS with the mask pattern;
• and
• a step of, by a Flit error detection unit of the error detector, detecting a forward error correction (FEC) symbol error in the portion corresponding to the Flit for each error correction code (ECC) group, counting the number of FEC symbol errors, and determining an ECC group in which the number of FEC symbol errors exceeds the threshold value, to be the Flit error.