×

Data communication in CATV system

  • US 4,454,538 A
  • Filed: 07/23/1982
  • Issued: 06/12/1984
  • Est. Priority Date: 07/24/1981
  • Status: Expired due to Fees
First Claim
Patent Images

1. In a CATV system in which a central facility is connected through a plurality of cables to a number of terminal units such a manner that two-way communication can be effected between said central facility and said terminal units, wherein an input signal at a first frequency sent from said facility and said terminal units comprises a video signal component and a discrete terminal unit signal component, said first frequency of said input signal corresponding to a first program channel, and an output signal at a second frequency sent from said terminal units to said facility comprises a discrete terminal unit output signal, said terminal units comprising:

  • means for producing a first signal substantially equal in frequency to said first frequency of said input signal corresponding to said first program channel;

    mixing means for mixing said first signal with said input signal and producing a second signal;

    means for extracting said discrete terminal unit signal component from said second signal, and producing a third signal;

    means for receiving said third signal and producing said output signal; and

    means for transmitting said output signal to said facility, said second frequency of said output signal being substantially a preset fraction of said first frequency of said input signal corresponding to said first program channel.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×