An enhanced RF television scrambling system using phase modulation

A novel system for scrambling and descrambling RF television signals for CATV service security is presented. The system has been designed to be low cost, easily manufactured, reliable, and more secure than conventional RF technology. The system uses RF carrier phase modulation to enhance the economy of the RF sync suppression techniques with some of the video and audio signal security attributes of baseband systems. Surface-acoustic-wave filters are used to implement the modulation. The encoding system provides a means of reliable, noise-insensitive addressable data communication to subscribers´ descramblers without the use of a separate data channel