你好：
我们使用AD9148的single mode模式，现在需要进行板内的多片同步。
按照single mode的要求，我们240M直接播放的时候，dci时钟应该是480MHz，frame的频率应该是240MHz。
而按照同步的要求，Data Rate Mode Synchronization：Reset the FIFO by strobing the FRAME signal for at least the
time interval needed to load complete data to the four DACs.
Resetting the FIFO ensures that the correct data is being
read from the FIFO of each of the devices simultaneously.
This completes the synchronization procedure, and at this
stage, all devices should be synchronized.
FIFO Rate Mode：Reset the FIFO by strobing the FRAME signal high for at least the
time interval needed to load complete data to the four DACs.
Resetting the FIFO ensures that the correct data is being
read from the FIFO of each of the devices simultaneously.
This completes the synchronization procedure, and at this
stage, all devices should be synchronized.
无论哪种同步模式，frame处理是一致的；都是用来处理fifo的复位；按此推轮，frame的频率应该是数据率的1/8,此时的占空比是否可设置为50%？
