Cable AML radios can provide significant cost savings when used to transport HITS (Headend in the Sky) signals from one headend to neighboring headends.

The HITS system delivers QPSK digital signals to cable headends via satellite. Each carriers is modulated with five to eight digitally compressed video programs at 27 Mbps. At each headend the HITS signals are downconverted and their modulation is changed from QPSK to 64-QAM so that each carrier fits within the standard 6 MHz channel bandwidth. From one to fifteen digitally modulated 64-QAM carriers can be carried in the cable plant.

Four ATX-033 transmitters racked to provide digital signal to 4 separate headends Cable AML’s broadband system can be used to transport the 64-QAM carriers from a master headend to nearby headends, thus avoiding the expense of duplicating the HITS satellite receiver and trans-modulation equipment.

Tests of standard production Cable AML’s broadband transmitters and receivers were made at the National Digital Television Center by R&A Management, GI, TCI, and Cable AML to characterize the performance of the equipment when used in the digital-only transport mode.

Cable AML’s links are also used by Cable TV Operators to transport a combination of analog and digital signals. For example, a typical combination might include 56 VSB-AM analog video channels, 15 digital video carriers (64-QAM), and several QPSK data carriers. The data carriers are for EPG (Electronic Program Guide) information, conditional access, control data, and DMX (Digital Audio Signal).