Signal distribution device for a cable television

• US RE29,997 E
• Filed: 10/03/1977
• Issued: 05/15/1979
• Est. Priority Date: 12/24/1974
• Status: Expired due to Term

• Current Assignee: Hyundai Electronics America Incorporated (SK Hynix Inc.), Tv/com Technololgies, Inc.
• Original Assignee: Oak Holland BV
• Inventors: den Toonder, Pieter
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Masinick, Michael A.
• Application Number:
  US05/838,990
• Time in Patent Office: 589 Days
• Field of Search: 325/308, 325/132, 325/32, 325/34, 179/15 BD, 358/114, 358/122
• US Class Current: 370/486
• CPC Class Codes: H04N 7/166 Passage/non-passage of the television signal, e.g. jamming, band suppression scrambling and descrambling H04N7/167

Abstract

A cable television signal distribution system provides a plurality of television programs and radio programs which are transmitted in frequency multiplex to a plurality of subscriber drop lines. A data receiver and logic control unit, after decoding suitable supplied codes, control the operation of a plurality of high frequency switches by which the received programs can be switched and/or jammed from a remote locate to selectively provide subscribers the desired program.

Claims

1. A signal distribution means for use with a cable television network having a supply line in which a plurality of TV programs are transmitted in frequency multiplex to a plurality of subscriber drop lines, said means including a data receiver connected to the supply line a logic control unit connected to said data receiver, a plurality of high frequency switches controlled by said logic control unit, and a jamming oscillator connected to each high frequency switch, said high frequency switches responding to control signals from said data receiver and logic control unit to provide jamming signals from designated oscillators to said subscriber drop lines to prevent clear reception of designated TV programs.

2. The means of claim 1 further characterized by and including attenuation means connected between each oscillator and its associated high frequency switch.

3. The means of claim 1 further characterized in that each high frequency switch includes three unidirectionally connected diodes, the junctions on each side of the center diode being connected to ground by the series combination of a diode and capacitor.

4. The means of claim 3 further characterized in that the cathode of one series diode is connected to the cathode of the center diode with the anode of the other series diode being connected to the anode of the center diode.

5. The means of claim 4 further characterized by and including capacitors connected to the cathode of the first of said three unidirectionally directed diodes and to the anode of the third of said three unidirectionally connected diodes.

6. The means of claim 5 further characterized by and including a series resistive circuit shunting said center diode.

7. Signal distribution means for use with a cable television network having a supply line on which a plurality of TV programs are transmitted in frequency multiplex to a plurality of subscriber drop lines, said means including a connection from the supply line to each subscriber, a data receiver connected to the supply line, a logic control unit connected to said data receiver, and a plurality of high frequency switches controlled by said logic control unit, each high frequency switch including a low frequency oscillator for variably tuning said high frequency switch, said high frequency switches responding to control signals from said data receiver and logic control unit to prevent clear reception of designated programs.

8. The means of claim 7 further characterized by and including a jamming oscillator connected in series with each high frequency switch.

9. The means of claim 7 further characterized in that each high frequency switch includes a parallel circuit of an inductance and a variable capacitance, said low frequency oscillator being connected to said variable capacitance.