The need for extended bandwidth in cable communications systems is obvious. The rapid growth of cable systems in the u.s.A. is encouraging the proliferation of program services for cable distribution. The tree structured broad- band nature of cable systems means that capacity must be provided for all of the service to be distributed irrespective of relative popularity. Cable losses follow a square root of frequency law which makes bandwidth extension attractive as a means of increasing channel capacity. Reducing the number of amplifiers in cascade and the use of coherent carrier systems makes it possible for extended bandwidth cable systems to handle the additional channel loading with no more distortion than in present 35 channel systems.