This module can detect, compare and contrast two sources of analogue video sync signals for differences and real-time behaviour. Each source may consist of one or two signals, black burst or tri-level, or mixed of both. If a black burst signal with VITC is connected, the VITC will be  monitored as well. Both sources should generate identical signals and in the event of a failure, SB automatically switches to the other correct source. The SB module forms the central part of a redundant video sync system and/or redundant VITC generator system, especially in a real-time application.