Television signal distribution system

• US 3,968,327 A
• Filed: 06/15/1973
• Issued: 07/06/1976
• Est. Priority Date: 06/15/1973
• Status: Expired due to Term

• Current Assignee: Sundstrand Corporation (Rtx Corporation)
• Original Assignee: Sundstrand Data Control, Inc. (Rtx Corporation)
• Inventors: Gregg, Ray V. III
• Primary Examiner(s): Britton, Howard W.
• Assistant Examiner(s): Masinick, Michael A.
• Application Number:
  US05/370,402
• Time in Patent Office: 1,117 Days
• Field of Search: 178/DIG. 13, 178/6.8, 178/DIG. 8, 178/5.1, 179/1 B, 325/308
• US Class Current: 725/85
• CPC Class Codes: H04N 2007/1739 the upstream communication being transmitted via a separate link, e.g. telephone line
• CPC Class Codes: H04N 7/166 Passage/non-passage of the television signal, e.g. jamming, band suppression scrambling and descrambling H04N7/167
• CPC Class Codes: H04N 7/17363 at or near the user terminal

Abstract

A television signal distribution system for special programs in an establishment, as a motel, with plural receivers. A master antenna is connected through a cable distribution system with each of the receivers. Special program signals, as of a movie, are distributed through the cable on an unused channel. A filter at each receiver blocks the special signal from the receiver. A circuit actuated from a central control station is directed to the room over the telephone system and disables the filter enabling the occupant of the room to watch the special program.

Claims

1. A television signal distribution system for a plurality of multiple channel receivers, comprising:

a source of television signals for each of a plurality of channels;

circuit means for conducting said television signals from said source to each of said receivers;

further circuit means connected from said control station to each of said receivers, independent of said television signal conducting circuit means;

band suppression channel filters for at least one of said channels, connected between said circuit means and each of said receivers;

a central control station;

means actuated by an operator at said central control station and operative without manipulation of any circuit control by the viewer at the receiver to transmit a momentary channel filter control signal to a selected receiver from said control station over said further circuit means;

signal detecting means requiring a source of operating potential at each of said receivers, responsive to said channel filter control signal for disabling the channel filter at a selected receiver, including a hold circuit maintaining the channel filter in disabled condition following termination of said control signal; and

means providing said operating potential, said receiver having a selectively operable power circuit for connection with an alternating power source, and said means providing the operating potential for said channel filter control signal detecting means being actuated upon operation of said receiver and including a transformer with a primary winding connected in series with the power circuit of said receiver.

2. A television signal distribution system for a plurality of multiple channel receivers, comprising:

a source of television signals for each of a plurality of channels;

circuit means for conducting said television signals from said source to each of said receivers;

further circuit means connected from said control station to each of said receivers, independent of said television signal conducting circuit means;

band suppression channel filters for at least one of said channels, connected between said circuit means and each of said receivers;

a central control station;

means actuated by an operator at said central control station and operative without manipulation of any circuit control by the viewer at the receiver to transmit a momentary channel filter control signal to a selected receiver from said control station over said further circuit means;

signal detecting means requiring a source of operating potential at each of said receivers, responsive to said channel filter control signal for disabling the channel filter at a selected receiver, including a hold circuit maintaining the channel filter in disabled condition following termination of said control signal;

means providing said operating potenial, said receiver having a selectively operable power circuit for connection with an alternating power source, and said means providing the operating potential for said channel filter control signal detecting means being actuated upon operation of said receiver and including a transformer with a primary winding connected in series with the power circuit of said receiver; and

means to interrupt said hold circuit, including means providing a time delay in such interruption.

3. A television signal distribution system for a plurality of multiple channel receivers, comprising:

a source of television signals for each of a plurality of channels;

circuit means including a low impedance transmission line connected from said source of television signals to each of said receivers for conducting said television signals from said source to each of said receivers;

a band suppression channel filter for at least one of said channels connected between said circuit means and each of said receivers, said filter having a series connected inductor and capacitor connected in shunt across said transmission line and resonant at the frequency of the video carrier of the television signal;

a central control station; and

means actuated by an operator at said central control station and operative without manipulation of any circuit control by the viewer at the receiver to disable the channel filter at a selected receiver.

4. The television signal distribution system of claim 3 including an electromechanical relay having low resistance contacts connecting said inductor and capacitor with said transmission line.

5. The television signal distribution system of claim 4 in which said band suppression filter is a pi network with two series resonant inductor-capacitor circuits connected in shunt acros said transmission line and with a third capacitor connected in series with the transmission line between said two shunt circuits, and two separate electromechanical relays having low resistance contacts connecting the shunt circuits with the transmission line.