Multiple switching and alarm device - is for carrier supply equipment in carrier frequency systems

摘要

The device switches in a stand-by unit in phase controlled oscillators, and at the same time monitors output levels and synchronism of operating and stand-by oscillators. Similar switching means are provided on the operating and replacement side for each side control. Criteria for level and synchronisation are on both sides applied to a monitoring circuit. Synchronisation criteria are generated in synchronisation detectors before the switching over contacts, while the level criteria are generated by rectifiers following the contacts. A monitoring circuit is connected to first inputs of two first NAND gates, and these inputs are interconnected by diodes of opposite polarities; their second inputs are disconnected for operation and replacement, and their outputs are connected to a first pair of terminals and also to first inputs of two second NAND gates.