The SMS2012 SONET/SDH is a fully integrated Clock Data Recovery (CDR) SONET OC-3 interface core designed for multiple integration on a single IC in a typical System-On-Chip (SOC) application. SMS2012 interfacing to the rest of building blocks on chip is fully customizable. For example, an optional mux demux module can be interconnected to the SMS2012 core making it capable of performing all the necessary serial-to-parallel and parallel to-serial functions in compliance with SONET/SDH transmission standards. The SMS2012 block diagram is shown in Figure 1. In a typical SOC application, 16 instances of SMS2011 (SONET/SDH OC-3 TRANSCEIVER / CDR), 4 instances of SMS2012 and an additional 2 million of logic gates can be integrated on a single chip.
SMS2012 CDR block contains a clock recovery unit with an integrated loop filter allowing the use of a slower clock reference. SMS2012 performs the clock recovery task by utilizing proprietary Advanced Signal Processing techniques. The interface to an external optical module could be either LVPECL or LVDS. The low jitter LVPECL/ LVDS interface guarantees compliance with the bit-error rate requirements of the ITU standards.
