CATV distribution system, especially adapted for off-premises premium channel interdiction

摘要

Equipment for use in CATV lines and a system for distribution of CATV signals and for power to operate CATV line equipment having active devices which require power is described. The system distributes CATV signals to subscribers who have ordered different levels of service (basic service without premium channels or different groups of premium channels). Housings are located in proximity to the premises of both actual subscribers and potential subscribers, and have like covers which contain tapping electronics (a directional coupler, line equalizers and power bypassing circuit). The cover has ports at opposite ends and an additional port at one end. The tapping electronics is located on a seizure board having seizure blocks spaced from each other along one edge of the board. The seizure board is rotatable ninety degrees (90 DEG ) so that the blocks are aligned with the ports at the opposite ends of the cover when the cover and housing unit are aerial mounted or with the ports at one end of the cover to receive the cable when the housing is pedestal mounted. Different enclosure units are attached to the cover and are configured and equipped with different types of electronics depending upon the level of service and/or the technology used to control the transmission of the CATV signals in accordance with the level of service for particular subscribers. A larger enclosure unit contains interdiction electronics which is addressable by signals from the head end of the CATV system to control frequency agile oscillators which generate the signals for jamming selected premium channels. A smaller enclosure unit contains the splitting electronics and may contain band reject filter(s) which block transmission of premium channels not ordered by the subscribers. The housing in proximity to potential subscriber premises has an enclosure unit provided by a plate and the tapping circuits are terminated with loads simulating the subscriber loads. If desired a circuit board having a splitter may be located in the housing and connectors attached to the plate. External band reject filters may be mounted on the plate at the connectors. Power distribution along the cable is controlled by bypass circuits, containing an RF choke and switching means (a jumper) which is connected across a capacitor which blocks power (60 Hz AC) so that the power bypass circuit does not adversely affect the transmission of the RF CATV signals.