IP data traffic is increasing continuously due to the recent rollout of 5G mobile communications and spread of IoT. Data centers supporting large-volume data communications are not only progressing with introduction of 400-GbE communications technology, but are also examining introduction of 800-GbE and 1-TbE technologies to support future large-capacity transmissions. The 200 and 400-GbE speeds standardized in 2017 adopted use of the PAM4 format to increase transmission capacities. Although the PAM4 format using 4 values doubles the transmission capacity of the earlier NRZ format using two values, the signal-to-noise ratio (SNR) is degraded by about 10 dB. At 200 and 400-GbE Phy layer transmission, due to the upper limit on the transmission speed and the degraded SNR, use of PAM4 is premised on adoption of Forward Error Correction (FEC) technology, without which it would be difficult to achieve the error-free transmissions that characterize the NRZ format
This application note explains the Signal Quality Analyzer-R (SQA-R) MP1900A FEC Solution and describes a concrete example of the FEC Rx test using the MU196040B PAM4 ED FEC Symbol Capture function.
