Thank you Chee for the remark. And thank you Damian for your notification on changing subcarriers in BER test set. That was a careless mistake I made. But when I set Bit rate as 10Gbps in your implementation without changing the number of subcarriers or anything else, I get BER=0.4 and since the Bit rate is calculated in script mode in BER Test Set, there’s no need to change it manually. So I just changed the bit rate, I don’t know what else to change.