SBAS997A February 2020 – June 2021 ADC09DJ1300-Q1 , ADC09QJ1300-Q1 , ADC09SJ1300-Q1
Synchronization of blocks, multiblocks and extended multiblocks by monitoring the sync header of each block and EoMB and EoEMB bit of the sync header stream. A block always begins with a 0 to 1 or 1 to 0 transition (sync header). A single missed sync header can occur due to a bit error, however if there are a number of sync header errors within a set number of blocks, then block synchronization has been lost and block synchronization should be reinitialized. It is possible to still have block synchronization, but to lose multiblock or extended multiblock synchronization. Multiblock synchronization is monitored by looking for the EoMB signal, 00001, at the end of the sync header stream for each multiblock. If multiple EoMB signals are erroneous within a number of blocks, multiblock synchronization has been lost and multiblock synchronization should be reinitialized. If an erroneous EoEMB bit is received for multiple extended multiblocks within a number of extended multiblocks, such as a 1 for a multiblock that is not the end of an extended multiblock or a 0 for a multiblock that is the end of an extended multiblock, then multiblock synchronization is lost and extended multiblock synchronization should be reinitialized. If multiblock or extended multiblock synchronizaton is lost, SYSREF should be applied to the erroneous devices in order to reestablish the LEMC before the synchronization process begins.