Patent ID: 6526070
Filing Date: 2003-02-25
Classification: H04N

Abstract:
A network interface apparatus for providing data transmissions to a network controller that are synchronized with transmissions from other network interface apparatuses to the network controller, the apparatus comprising:a clock providing a local time; a message receiver for receiving messages from the network controller; a time tag generator for recording local times of arrival at the interface unit of said messages; an elapsed time computation unit for determining an elapsed local time between network controller time stamps contained in said messages using said time tags; a phase lock loop for generating a recovered time that is synchronized to the network controller from said elapsed local time and said network controller time stamps; and a transmission unit for generating data transmissions from the network interface unit to the network control unit in accordance with said synchronized recovered time and a transmission time slot, wherein determining an elapsed local time between arrivals of network controller timestamps comprises determining local times of arrival of first and second timestamps associated with first and second messages using an elapsed local time per received byte, a byte number of each timestamp within said respective first and second messages, and time tags associated with said first and second messages.