SNAA333 April   2020 CDCE6214-Q1

 

  1.   eAVB Media Clock Synchronization Using CDCE6214-Q1 Clock Generator
    1.     Trademarks
    2. 1 Introduction
    3. 2 AVB Protocols and Network Structure
    4. 3 AVB End Station Architecture
    5. 4 Talker, Listener, Presentation Time, and Media Clock Synchronization
      1. 4.1 Talker and Presentation Time
      2. 4.2 Listener and Media Clock Synchronization
    6. 5 Reference CDCE6214-Q1 Schematic and Programming Guide
    7. 6 Summary
    8. 7 References

6 Summary

This application note answers the two frequently asked questions on AVB synchronization:

  1. Multiple speakers attached to different Listeners can start and stop playing at precisely the same time by having the presentation timestamps added to the 1722 data packets. All samples are specified to release to AVTP stream depacketizer buffers at the scheduled presentation time.
  2. Multiple Talkers and Listeners can achieve sampling rate synchronization by comparing the local and source media clock period and fine tuning the local media clock frequency.

As described in Section 5, CDCE6214-Q1 is a simple but efficient frequency adjustable PLL that can be used for media clock generation and synchronization. Besides, CDCE6214-Q1 has less than 2.1 ps integrated fractional jitter. It also provides features such as output slew rate control that can slow down the output edge rate and meet EMI requirements for the automotive industry.