SELECTIVE VIDEO RECEPTION INHIBITING APPARATUS

• US 3,859,457 A
• Filed: 03/28/1973
• Issued: 01/07/1975
• Est. Priority Date: 05/24/1971
• Status: Expired due to Term

• Current Assignee: Donald Kirk Jr
• Original Assignee: Donald Kirk Jr
• Inventors: Kirk, Donald Jr.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Buczinski, S. C.
• Application Number:
  US05/345,684
• Time in Patent Office: 650 Days
• Field of Search: 325/461,477,132,308,483 178/5.1,DIG.13
• US Class Current: 380/208
• CPC Class Codes: H04K 1/04 by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band
• CPC Class Codes: H04N 21/2543 Billing , e.g. for subscription services payment schemes, architectures or protocols G06Q20/00; e-commerce G06Q30/00; arrangements for billing for the use of broadcast information or broadcast-related information H04H60/21
• CPC Class Codes: H04N 7/166 Passage/non-passage of the television signal, e.g. jamming, band suppression scrambling and descrambling H04N7/167

Abstract

Selective video suppression apparatus, operative on a persubscriber basis, comprises a band elimination, notch filter tuned to the spectrum of a video signal to be selectively inhibited. The filter exhibits relatively little attenuation, having only a de minimus effect per se on signal reception. However, in accordance with the principles of the present invention, filter attenuation is modulated at a rate exceeding the response capacity of a television receiver automatic gain control circuit. The resulting amplitude modulated signal reaching the television receiver is essentially unrecoverable, obviating receiver synchronization, color subcarrier recovery, and generally inhibiting video reception.

Claims

1. In combination, cable video propagating means, means connected to said cable means for supplying thereto at least one video signal, and video reception inhibiting means connected to said cable means for suppressing reception of said video signal on said cable means, said reception inhibiting means comprising electronically controlled variable attenuation filter means tuned to the spectrum of said video signal, said filter means including means exhibiting an attenuation dependent upon the value of an electronic control signal, and filter attenuation modulating signal generator means for supplying a control signal of relatively high frequency to said filter means for varying the attenuation characteristic of said filter means.

2. A combination as in claim 1 wherein said filter means comprises a series resonant circuit, and electronically controlled means connected in parallel with a portion of said series resonant circuit to selectively alternately vary the radio frequency impedance state of said resonant circuit portion.

3. A combination as in claim 2 wherein said series resonant circuits comprise a series connected capacitance and inductance, and wherein said alternating radio frequency impedance means comprises a diode connected to the junction of said capacitance and inductance, and oscillator means for selectively forward biasing said diode.

4. A combination as in claim 3 further comprising additional capacitance means connected to the junction between said diode and said oscillator means, the capacitance of said additional capacitance means greatly exceeding that of said capacitance included in said series tuned circuit.

5. A combination as in claim 4 further comprising a source of Fixed potential, and switching means for connecting said diode to one of said potential source and said oscillating means.

6. A combination as in claim 3 wherein said inductance in said series tuned circuit comprises a parallel resonant circuit tuned below resonance.

7. A combination as in claim 2 wherein said electronically controlled means includes means for varying the resonant frequency of said series resonant circuit.

8. A combination as in claim 1 further comprising video receiving means connected to said cable means.

9. A combination as in claim 8 wherein said video signal supplying means supplies said at least one signal in a form not recoverable by a conventional television receiver, and wherein said signal receiving means comprises converter means connected to said cable means for converting said at least one signal to a form which is recoverable by said receiver.

10. In combination in apparatus for inhibiting reception of a video signal distributed via a signal distribution cable, a band elimination filter means exhibiting an attenuation characteristic which varies in degree of attenuation as a function of an input control signal, and filter attenuation modulating signal generator means connected to said band elimination filter for supplying thereto a control signal for varying the attenuation effected by said filter means, said generator means including means for supplying a signal varying at a rate which exceeds the automatic gain control compensation capacity of television receivers.

11. A combination as in claim 10 wherein said band elimination filter means comprises a series resonant circuit, and electronically controlled means connected in parallel with a portion of said series resonant circuit to selectively alternately vary the radio frequency impedance state of said resonant circuit portion.

12. A combination as in claim 11 wherein said series resonant circuits comprise a series connected capacitance and inductance, and wherein said alternating radio frequency impedance means comprises a diode connected to the junction of said capacitance and inductance, and oscillator means for selectively forward biasing said diode.

13. A combination as in claim 12 further comprising additional capacitance means connected to the junction between said diode and said oscillator means.

14. A combination as in claim 13 further comprising a source of fixed potential and switching means for connecting said diode to one of said potential source and said oscillating means.

15. A combination as in claim 10 further comprising video receiving means connected to said cable means.

16. A combination as in claim 15 wherein said video signal supplying means supplies said at least one signal in a form not recoverable by a conventional television receiver, and wherein said signal receiving means comprises converter means connected to said cable means for converting said at least one signal to a form which is recoverable by said receiver.