Optical network unit-device for use in digital broadcast and communications system for providing broadcast and communication services, has edge-quadrature amplitude modulation unit modulating reception signal to radio frequency-signal

摘要

The device has a cable-modem (120) receiving synchronization information from a head point (102) via an optical line. An edge-quadrature amplitude modulation unit carries out synchronization with a cable modem closing system (104) on the bases of the information, where the cable modem closing system is provided in the head point. The modulation unit modulates reception signal to a radio frequency-signal for a subscriber device and connected with the subscriber device by a coaxial line. An optical multiplexer receives the reception signal via the optical line. Independent claims are also included for the following: (1) a method for performing synchronization in a cable network structure (2) a head point device comprising a cable modem closing system.