V-Series Transceiver PHY IP Core User Guide

ID 683171
Date 7/26/2022
Public
Document Table of Contents

17.7.2. Duty Cycle Calibration

The TX clocks generated by the CMU and travel across the clock network may introduce duty cycle distortion (DCD). DCD calibration function reduces this distortion.
DCD runs once during device power up and you can manually trigger DCD after power up. Altera recommends that you enable DCD for Arria V and Cyclone V devices if either of the following conditions is true:
  • The data rate is greater than or equal to 4.9152 Gbps
  • The design dynamically reconfigures the TX PLL and the data rate is greater than or equal to 4.9152 Gbps