Pulsed leakage tagging signal

• US 6,307,593 B1
• Filed: 10/03/1997
• Issued: 10/23/2001
• Est. Priority Date: 10/03/1997
• Status: Expired due to Term

• Current Assignee: Wavetek Corp. (Lumentum Holdings Inc.)
• Original Assignee: Wavetek Corp. (Lumentum Holdings Inc.)
• Inventors: Shi, Pingnan, Bowyer, Andrew E.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): NATNAEL, PAULOS M
• Application Number:
  US08/943,652
• Time in Patent Office: 1,481 Days
• Field of Search: 348/461, 348/192, 348/193, 348/6, 348/2, 348/3, 348/4, 348/476, 348/477, 348/478, 348/479, 455/67.1, 455/67.3, 455/67.4, 455/47, 455/115
• US Class Current: 348/461
• CPC Class Codes: H04N 17/00 Diagnosis, testing or measuring for television systems or their details
• CPC Class Codes: H04N 7/087 with signal insertion during the vertical blanking interval only

Abstract

A method of transmitting a leakage tagging signal includes inserting a tagging signal into a CATV television signal only during portions of the television signal in which control information is present. A method according to the present invention is a method of transmitting a tagging signal in a communication system, the communication system transmitting television signals comprising control information and program information. One step of the method includes generating a tagging signal that is detectable by corresponding leakage detecting equipment. The method also includes the step of identifying a portion of a television signal in which control information is present. Finally, the method of the present invention encompasses inserting the tagging signal into the television signal only during the portion of the television signal in which control information is present.

Claims

1. A method of transmitting a tagging signal in a communication system, the communication system transmitting television signals comprising control information and program information, the method comprising:

a) generating a tagging signal, said signal being detectable by corresponding leakage detecting equipment;

b) identifying a portion of a television signal in which control information is present, the control information comprising a vertical interval;

c) inserting the tagging signal into the television signal only during the portion of the television signal in which the vertical interval is present.

2. The method of claim 1 wherein step c) further comprises modulating a carrier signal with the tagging signal only during the portion of the television signal in which the vertical interval is present and summing the carrier signal modulated with the tagging signal with the television signal.

3. The method of claim 2 wherein step c) further comprises modulating a carrier signal with the tagging signal, wherein the carrier signal has a frequency within the vestigial sideband associated with the television signal.

4. The method of claim 3 wherein step c) further comprises modulating a carrier signal with the tagging signal, wherein the carrier signal has a frequency within 0.9 MHz to 1.15 MHz below the CATV carrier signal frequency of the television signal.

5. The method of claim 1 wherein step a) further comprises generating an oscillating tagging signal.

6. The method of claim 4 wherein step a) further comprises generating a 20-29 Hz oscillating tagging signal.

7. The method of claim 1 wherein step c) further comprises modulating a carrier signal with the tagging signal only during the portion of the television signal in which the vertical is present and summing the carrier signal modulated with the tagging signal with the television signal.

8. The method of claim 7 wherein step c) further comprises modulating a carrier signal with the tagging signal, the carrier signal having a frequency within the vestigial sideband associated with the television signal.

9. The method of claim 1 wherein step c) further comprises modulating the television signal with the tagging signal only during the portion of the television signal in which control information is present.

10. An arrangement for the insertion of a tagging signal into a television signal, the television signal comprising control information and program information, the television signal being transmitted by a communication system, the arrangement comprising:

a) an input connected to a source of television signals comprising control information and program information, the control information including a vertical interval;

b) a tagging signal generator operable to generate a tagging signal that is detectable by corresponding leakage detecting equipment; and

c) a signal inserter, coupled to the input and the tagging signal generator, operable to insert the tagging signal into the television signal;

d) a switch operably coupled to the signal inserter to cause the signal inserter to insert the tagging signal only during the portion of the television signal in which the vertical interval is present.

11. The arrangement of claim 10 further comprises e) a detector coupled to the input, the detector operable to identify a portion of the television signal in which control information is present and wherein said detector provides a signal to the switch indicative of the presence of control information in the television signal.

12. The arrangement of claim 10 further comprising an RF oscillator connected to an RF input of said switch, and wherein the signal inserter comprises an amplitude modulator and a summation device, said amplitude modulator coupled to an RF output of said switch, said amplitude modulator further comprising an RF output connected to the summation device, and a control input connected to said tagging signal generator.

13. The arrangement of claim 12 wherein the RF oscillator is operable to generate a carrier signal having a frequency within the vestigial sideband associated with the television signal.

14. The arrangement of claim 13 wherein the RF oscillator is operable to generate a carrier signal having a frequency within 0.9 MHz to 1.15 MHz below a CATV carrier signal frequency of the television signal.

15. The arrangement of claim 12 wherein the control information further comprises a vertical interval and said switch is further operable to cause the signal inserter to insert the tagging signal into the television signal only during the portion of the television signal in which the vertical interval is present.

16. The arrangement of claim 10 wherein said signal inserter comprises an amplitude modulator connected to the input, said amplitude modulator further comprising an RF output, and a control input connected to the switch.

17. The arrangement of claim 10 wherein the tagging signal generator is an oscillator.

18. The arrangement of claim 17 wherein the oscillator is operable to generate a 20-29 Hz oscillating signal.

19. The arrangement of claim 10 wherein the control information further comprises a vertical interval and said switch is further operable to cause the signal inserter to insert the tagging signal into the television signal only during the portion of the television signal in which the vertical interval is present.

20. An arrangement for the insertion of a tagging signal into a television signal, the television signal comprising control information and program information, the control information including a vertical interval, the television signal being transmitted by a communication system, the arrangement comprising:

a) an input connected to a source of television signals comprising control information and program information;

b) a tag insertion operable to

generate a tagging signal, said signal being detectable by corresponding leakage detecting equipment;

identify a portion of a television signal in which the vertical interval is present; and

insert the tagging signal into the television signal only during the portion of the television signal in which the vertical interval is present.

21. The arrangement of claim 20 wherein the tag insertion circuit further includes an RF oscillator operable to generate a carrier signal, and wherein the tag insertion circuit is further operable to:

modulate the carrier signal with the tagging signal only during the portion of the television signal in which the vertical interval is present; and

sum the carrier signal modulated with the tagging signal with the television signal.

22. The arrangement of claim 21 wherein the RF oscillator is further operable to generate a carrier signal having a frequency within the vestigial sideband associated with the television signal.

23. The arrangement of claim 21 wherein the RF oscillator is further operable to generate a carrier signal having a frequency within 0.9 MHz to 1.15 MHz below the CATV carrier signal frequency of the television signal.

24. The arrangement of claim 20 wherein the tag insertion circuit further includes an oscillator for generating the tagging signal.

25. The arrangement of claim 24 wherein the oscillator is operable to generate a 20-29 Hz oscillating tagging signal.

26. The arrangement of claim 20 wherein the tag insertion circuit is further operable to modulate the television signal with the tagging signal only during the portion of the television signal in which control information is present.

27. A method transmitting a tagging signal in a communication system, the communication system transmitting television signals in one or more CATV channels, each channel associated with a carrier frequency, an active sideband, and a vestigial sideband, the method comprising:

a) generating a tagging signal, said signal being detectable by corresponding leakage detecting equipment;

b) modulating a carrier signal with the tagging signal, said carrier signal having a frequency within a vestigial sideband associated with a CATV channel; and

c) combining the modulated carrier signal with a television signal transmitted in the communication system only during a portion of the television signal in which a vertical interval is present.

28. The method of claim 27 wherein the television signal further comprises control information and program information, and wherein step c) further comprises combining the modulated carrier signal with the television signal only during a portion of the television signal in which control information is present.

29. The method of claim 28 wherein step b) further comprises modulating the television signal with the tagging signal only during the portion of the television signal in which control information is present.

30. The method of claim 28 wherein the control information further comprises a vertical interval and step and step c) further comprises combining the tagging signal with the television signal only during the portion of the television signal in which the vertical interval is present.

31. The method of claim 27 wherein step a) further comprises generating a 20-29 Hz oscillating tagging signal.

32. The method of claim 27 wherein step b) further comprises modulating carrier signal with the tagging signal, wherein the carrier signal has a frequency within 0.9 MHz to 1.15 MHz below the CATV carrier signal frequency of the television signal.

33. A method transmitting a tagging signal in a communication system, the communication system transmitting television signals comprising control information and program information, the method comprising:

a) generating an oscillating tagging signal, said signal being detectable by corresponding leakage detecting equipment;

b) identifying a portion of a television signal in which control information is present;

c) inserting the tagging signal into the television signal only during the portion of the television signal in which control information is present.

34. The method of claim 33 wherein step c) further comprises modulating the television signal with the tagging signal only during the portion of the television signal in which control information is present.

35. An arrangement for the insertion of a tagging signal into a television signal, the television signal comprising control information and program information, the television signal being transmitted by a communication system, the arrangement comprising:

a) an input connected to a source of television signals comprising control information and program information;

b) a tag insertion circuit including an oscillator, the tag insertion circuit operable to

generate a tagging signal using the oscillator, said signal being detectable by corresponding leakage detecting equipment;

identify a portion of a television signal in which control information is present; and

insert the tagging signal into the television signal only during the portion of the television signal in which control information is present.

36. The arrangement of claim 35 wherein the tag insertion circuit is further operable to modulate the television signal with the tagging signal only during the portion of the television signal in which control information is present.