Digital Fiber Link Transporting Multiple Analog Bands for Agile Conversion

摘要

A digital (fiber optic) link transports one or more RF digital signal blocks, that when converted into analog and (optionally) converted to a RF center frequency with an D-A converter, form RF analog signal blocks. The RF analog signal block occupies a specified frequency band and is preferably capable of being distributed over a downstream coaxial portion of a HFC network and/or being broadcast. The D-A conversion is performed in a fiber node at a remote location where the transmission medium converts from digital optical fiber preferably to coaxial cable. The multiple RF digital signal blocks may be broadcast to multiple nodes or unicast to a single node. The RF signal blocks allow for any type of band-limited RF signal to be transported. The optical digital traffic to compose a RF analog signal blocks using a D-A converter may be point-to-point Ethernet, or may utilize a software-defined networking controller such as the one described in the OpenFlow™ specification, and may use buffering as necessary.

主权项

1. A transmission system comprising:
a circuit constructing a digital electrical signal stream that includes digital signal blocks directed to different fiber nodes connected to terminals belonging to different user groups, wherein the digital signal blocks directed to at least one of said fiber nodes carry information that is different from the information carried by digital signal blocks directed to the remaining fiber nodes; and a digital laser responsive to said digital electrical signal stream and sending digital optical signals to said different fiber nodes through optical paths.