Two-Way Multichannel Video Links
Multichannel video links for cable TV are also available with bi-directional capacity for systems that require a return path for transporting DOCSIS signals as well as other data carriers.
Unidirectional existing systems can be modified by adding a return path, which is achieved by adding a header and a receiver in return transmitter in the reception site.
The return path is designed to transport the DOCSIS header signals with QPSK 16-QAM or 64 QAM. In some cases the return transmission spectrum used in the band from 13 GHz down. Other versions use in the band of 13 GHz and return in the 18 GHz.
The configuration of dual band 13/18 GHz provides a substantial capacity to return data and simultaneously provides additional downstream capacity without sacrificing the band width of the existing system.
Both versions are available with various power levels and configurations transmitted indoor or outdoor installation.
Following is a simple block diagram of a two way multichannel video link: