Lower TDECQ indicates better optical signal quality and vertical eye opening. Verify TDECQ along with OMA, launch power, extinction ratio, receiver sensitivity, and link budget when selecting optical. If the SER value is smaller than the target SER value, Iterative Optimization is performed and the TDECQ measurement is made. Because modern high-speed links increasingly use PAM4 modulation (e., 50G, 100G, 200G, 400G), TDECQ has become the de facto key metric to ensure transmitter compliance and link reliability. In. The step-by-step process to perform a TDECQ measure-ment can depend on the specific oscilloscope vendor,1 but the method is explicitly documented in clause 121 of IEEE 802. In summary: Acquire the pattern-locked waveform for the short stress pattern random quaternary (SSPRQ)2 pattern with an. Adoption of high data rate transceivers like 400G has led to changes in how optical modules are tested. TDECQ — Transmitter and Dispersion Eye Closure. Can we use TDECQ to infer a better indication of transmitter performance? Can TDECQ tell us anything about this area? AWG output swing adjusted for different tap settings to keep optical ER at 4 dB as measured on the scope for all FIR settings. It's a power penalty metric that determines how much extra power is required at the receiver, from the transmitter, relative to an ideal.