AVB (Audio Video Bridging) protocols have been widely adopted to achieve time and clock synchronization over Ethernet, especially in automotive infotainment systems. CDCE6214-Q1 is a compact and ultra low-power programmable clock generator that supports output frequency tuning with less than 1-ppm step size. With the frequency margining capability, CDCE6214-Q1 is ideal for AVB media clock synchronization. This application report introduces AVB system architecture and explains media clock synchronization design with CDCE6214-Q1.
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Modern media systems for automotive infotainment and driver assistance are composed of multiple sensors, cameras, displayes, and content players. Point-to-point interconnections with shielded twisted pair or coaxial cables may not be practical for all of the required components. Ethernet is gaining more traction in the automotive audio visual market segment due to its convenience and fast transmission speed; however, standard asynchronous Ethernet networks do not carry clock synchronization information. One of the main goals of AVB protocols is to achieve time and clock synchronization over Ethernet.
Consider the example below where the live or playback audio and video are presented on two RSE (Rear Seat Entertainment) displays and multiple speakers at the same time. Speakers and RSE displays are connected to the Head Unit through Ethernet. For excellent user experience, media content should be lip synchronized, and both audio and video should be distributed to all speakers and displays synchronously.
Two types of A/V synchronization are required:
See Section 2, Section 3 and Section 4 to understand how to achieve the two types of synchronization and how the CDCE6214-Q1 device fits in media clock recovery.