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1. (WO1990006656) PROCEDE ET APPAREIL PERMETTANT D'EMPECHER LA RECEPTION D'UN CANAL DE TELEVISION CABLEE EN DEHORS DE LOCAUX AUTORISES
Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

What is claimed is:
1. A television premium channel interdiction apparatus for selectively jamming unauthorized premium programming on a broadband signal transmitted to a subscriber comprising:
a fixed local oscillator oscillating at a predetermined frequency;
a first mixer for mixing the broadband signal with the predetermined frequency output of the fixed local oscillator so as to mix a certain channel of the broadband signal;
a bandpass filter for filtering the output of the mixer, the bandpass filter having a passband offset above or below the television band of the broadband signal;
a variable local oscillator;
a second mixer for mixing the output of the bandpass filter with the output of the variable local oscillator; and
a combiner for combining the broadband signal with the output of the second mixer so as to selectively jam a particular channel.
2. The television premium channel interdiction apparatus of claim l, further comprising:
a controller for controlling the frequency of the variable local oscillator to selectably jam a particular channel.
3. The television premium channel interdiction apparatus of claim 2, wherein said controller controls the variable local oscillator to periodically jam a plurality of channels by frequency hopping.
4. The television premium channel interdiction apparatus of claim 3, further comprising:
a plurality of variable local oscillators and a plurality of second mixers, said plurality of second mixers connected across said second mixer and each of said plurality of variable local oscillators connected to a respective one of the plurality of second mixers, the controller controlling the frequency of each of the plurality of variable local oscillators.
5. The television premium channel interdiction apparatus of claim 4, further comprising: a plurality of switches connected between the variable local oscillators and the second mixers, the controller controlling the connection of each variable local oscillator to its respective mixer by its respective switch.
6. The television premium channel interdiction apparatus of claim 5, wherein the controller controls the switches so that a variable local oscillator tuned to jam a particular channel can selectively be connected to its respective mixer and selectively jam the premium programming when its respective switch for the variable local oscillator is closed.
7. The television premium channel interdiction apparatus of claim 1, wherein the frequency of the mixed local oscillator is chosen so as to mix a particular channel of the broadband signal to the passband frequency of the bandpass filter.
8. The television premium channel interdiction apparatus of claim 1, further comprising:
an isolation amplifier for amplifying the broadband signal before combining the broadband signal with the output of the second mixer.
9. Interdiction oscillator apparatus for use in a television premium channel interdiction system for selectively jamming unauthorized premium programming on a broadband signal transmitted to a subscriber comprising:
a fixed oscillator capable of oscillating at a fixed frequency;
a variable oscillator capable of oscillating at a certain frequency;
a mixer for mixing the output of the fixed oscillator and the output of the variable oscillator; and
a coupler for coupling the output of the mixer with the broadband signal to selectively jam a particular channel transmitted to the subscriber.
10. The oscillator for the television premium channel interdiction system according to claim 9, further comprising: a controller for controlling the frequency of the variable oscillator to a certain frequency to selectively jam the particular channel transmitted to the subscriber.
11. The oscillator for the television premium channel interdiction system according to claim 10, wherein the controller controls the frequency of the variable oscillator to selectively hop between certain frequencies to jam premium programming on particular, channels.
12. The oscillator for the television premium channel interdiction system according to claim 10, wherein the variable oscillator oscillates at a frequency out of the television band in a range of about 654 MHz to 816 MHz and is heterodyned with the fixed oscillator at about 600 MHz to produce a jamming signal, that falls in the television band of about 54 MHz to 216 MHz.
13. The oscillator for the television premium channel interdiction system according to claim 10, further comprising:
a plurality of variable oscillators connected in parallel with one another, the outputs of the plurality of variable oscillators connected to the input to the mixer, the controller controlling the frequency of each variable oscillator to selectively jam a particular channel.
14. The oscillator for the television premium channel interdiction system according to claim 13, further comprising:
switches connected between the output of each of the plurality of variable oscillators and the input to the mixer, said controller controlling the switching of the switches.
15. Gain control apparatus for use in a television premium channel interdiction system for selectively jamming unauthorized premium programs on a broadband signal transmitted to a subscriber, comprising:
a jamming oscillator for generating a jamming signal;
a variable attenuator for attenuating the jamming signal in accordance with a control signal to produce an attenuated jamming signal;

a combiner for combining the attenuated output of the variable attenuator with the broadband signal to provide a jammed signal;
a first comparator for comparing the magnitude of the attenuated jamming signal with the broadband signal; and
a controller for determining and providing the control signal to the variable attenuator in accordance with a predetermined function of the jamming oscillator frequency.
16. The gain control apparatus of claim 15, wherein the controller provides the control signal to the variable attenuator to decrease attenuation when the attenuated jamming signal effectively has a magnitude greater than the broadband signal determined from the predetermined function of the jamming oscillator frequency and increase attenuation when the attenuated jamming signal effectively has a magnitude less than the broadband signal determined from a function of the jamming oscillator frequency.
17. The gain control apparatus of claim 15, further comprising:
a first detector for detecting the attenuated magnitude of the attenuated jamming signal;
a second detector for detecting the magnitude of the broadband signal at a first frequency; and
the first comparator comparing the magnitude of the attenuated jamming signal and the broadband signal respectively in response to the first detector and the second detector.
18. The gain control apparatus of claim 17, wherein said second detector comprises a bandpass filter.
19. The gain control apparatus of claim 17, further comprising:
a third detector for detecting the magnitude of the broadband signal at a second frequency; and
a second comparator for comparing the magnitude of the attenuated jamming signal with the broadband signal respectively in response to the first detector and the third detector;

wherein said second detector further comprises a low frequency bandpass filter; and
wherein said third detector comprises a high frequency bandpass filter.
20. The gain control apparatus of claim 19, wherein said controller provides the control signal to the variable attenuator in accordance with the frequency of the jamming oscillator using a predetermined function stored in memory.
21. The gain control the apparatus of claim 20, wherein the predetermined function stored in memory is determined by interpolation, the interpolation performed between the results of the comparison of the attenuated jamming signal with the broadband signal in the first comparator and of the comparison of the attenuated jamming signal with the broadband signal in the second comparator.
22. The gain control the apparatus of claim 21, wherein the controller performs a calibration routine comprising the steps of: measuring high and low frequency gain, and interpolating between the high and low frequency gain to determine the predetermined function.

23. The gain control apparatus of claim 20, wherein the predetermined function is a known characteristic curve representative of the attenuation over frequency of the interdiction system transmission medium.
24. The gain control apparatus of claim 23, wherein the ends of the known characteristic curve are positioned between the required gain determined by comparison in the first comparator and the required gain determined by comparison in the second comparator.
25. The gain control apparatus of claim 20, further comprising:
a fourth detector for detecting the magnitude of the broadband signal at a third frequency; and
a third comparator for comparing the magnitude of the attenuated jamming signal with the broadband signal, respectively in response to the first detector and the fourth detector; and wherein said fourth detector further comprises a mid frequency bandpass filter.
26. A television premium channel interdiction apparatus for selectively jamming unauthorized premium programming transmitted to a subscriber comprising:
a plurality of four controlled oscillators for separately interdicting within an allocated continuous portion of a broadband cable television spectrum, the sum of all such allocated portions comprising the total spectrum to be jammed, the allocated continuous portion of the spectrum selected such that jamming signal frequency harmonic interference may be alleviated by a filter means, and
microprocessor actuation and control means, responsive to an addressed communication from a headend, for selectively actuating and controlling a plurality of n jamming frequencies provided by the plurality of four controlled oscillators, n being greater than or equal to four,
wherein the allocated portion for each of the four controlled oscillators are chosen from at least the following portions:
a first allocated portion comprising lowband channels two through five,
a second portion comprising midband channels fourteen through twenty-two,
a third portion comprising channels nineteen through twenty-two and highband channels seven through ten,
a fourth portion comprising highband channels eleven through thirteen and superband channels twenty-three through twenty-nine, and
a fifth portion comprising superband channels thirty into the hyperband through channel forty-one.
27. A television premium channel interdiction apparatus for selectively jamming unauthorized premium programming transmitted on a broadband signal comprising:
at least one variable frequency oscillator for interdicting a jamming signal; and a controller for addressing each at least one variable frequency oscillator to control the frequency of each at least one variable frequency oscillator in accordance with previously stored frequency calibration values.
28. The television premium channel interdiction apparatus of claim 27, wherein the controller determines the frequency calibration values based on the frequency output of each at least one variable frequency oscillator when each at least one variable frequency oscillator is addressed.
29. The television premium channel interdiction apparatus of claim 28, further comprising:
a prescaler responsive to the output of each at least one variable frequency oscillator;
a counter responsive to the output of the prescaler, wherein the controller is responsive to the counter for detecting the frequency of each at least one variable frequency oscillator; and
a digital-to-analog converter for addressing each at least one variable frequency oscillator by the controller.
30. The television premium channel interdiction apparatus of claim 27, further comprising:
a variable attenuator for attenuating the jamming signal, wherein the controller further controls the attenuation of the variable attenuator in accordance with previously stored attenuation calibration values.
31. The television premium channel interdiction apparatus of claim 30, wherein the controller determines the frequency calibration values during a frequency calibration routine based on the frequency output of each at last one variable frequency oscillator when each at least one variable frequency oscillator is addressed, and wherein the controller determines the attenuation calibration values, during an attenuation calibration routine based on the magnitude of the attenuated jamming signal and the magnitude of the broadband signal.

32. The television premium channel interdiction apparatus of claim 31, wherein the frequency calibration routine and the attenuation calibration routine are performed upon power-up.
33. The television premium channel interdiction apparatus of claim 31, wherein the frequency calibration routine or the attenuation calibration routine are performed at variable sequential intervals during operation of the interdiction apparatus.
34. The television premium channel interdiction apparatus of claim 27, wherein the frequency calibration values are previously stored by downloading to the controller from the headend.
35. The television premium channel interdiction apparatus of claim 30, wherein the attenuation calibration values are previously stored by downloading to the controller from the headend.
36. The television premium channel interdiction apparatus of claim 33, wherein the periodic intervals are controlled by downloading from the headend.
37. The gain control apparatus of claim 20, wherein the predetermined function is stored in a calibration mode as a lookup table with values representing attenuation in locations indicative of frequencies of the jamming oscillator.
38. The gain control apparatus of claim 21, wherein the interpolation is a straight line approximation.
39. The gain control apparatus of claim 21, wherein the interpolation is a simple cable slope interpolation.
40. The gain control of claim 25, wherein the predetermined function stored in memory is determined by interpolation, the interpolation performed between the required gains determined by comparison in the first comparator, the second comparator and the third comparator.
41. The gain control of claim 23, wherein the characteristic curve is downloaded to the controller from the headend.
42. A television premium channel interdiction method for selectively jamming unauthorized premium programming on a broadband signal transmitted to a subscriber comprising the steps of:
generating a predetermined frequency;

mixing the broadband signal with the predetermined frequency so as to mix a certain channel of the broadband signal;
filtering the result of the mixing with a passband offset above or below the television band of the broadband signal;
generating a variable frequency;
mixing the result of the filtering with the variable frequency; and
combining the broadband signal with the result of the last mixing step so as to selectively jam a particular channel.
43. The television premium channel interdiction method of claim 42, further comprising the step of:
controlling the generated variable frequency to selectably jam a particular channel.
44. The television premium channel interdiction method of claim 43, further comprising the step of:
frequency hopping to periodically jam a plurality of channels.
45. The television premium channel interdiction method of claim 44, further comprising the step of:
switching the variable frequency prior to mixing.
46. An interdiction method for use in a television premium channel interdiction system for selectively jamming unauthorized premium programming on a broadband signal transmitted to a subscriber comprising the steps of:
oscillating at a fixed frequency;
oscillating at a variable frequency;
mixing the fixed frequency and the variable frequency; and
coupling the mixed fixed frequency and variable frequency with the broadband signal to selectively jam a particular channel transmitted to the subscriber.
47. The interdiction method according to claim 46, further comprising the step of:
controlling the variable frequency to selectively jam the particular channel transmitted to the subscriber.

48. The interdiction method according to claim 47, further comprising the step of:
frequency hopping between particular frequencies to jam premium programming on particular channels.
49. The interdiction method according to claim 47, wherein the variable frequency is out of the television band in a range of about 654 MHz to 816 MHz and is heterodyned with the fixed frequency at about 600 MHz to produce a jamming signal that falls in the television band of about 54 MHz to 216 MHz.
50. The interdiction method according to claim 46, further comprising:
switching the variable frequency before mixing.
51. A television premium channel interdiction gain control method for use in an indiction apparatus for selectively jamming unauthorized premium programs on a broadband signal transmitted to a subscriber, comprising the steps of:
generating a jamming signal;
variably attenuating the jamming signal to produce an attenuated jamming signal;
combining the attenuated jamming signal with the broadband signal to provide a jammed signal;
comparing the magnitude of the attenuated jamming signal with the broadband signal; and
determining and providing control of the variable attenuation in accordance with a predetermined function of the jamming oscillator frequency.
52. The gain control method of claim 51, wherein the step of providing control includes the step of decreasing attenuation when the attenuated jamming signal effectively has a magnitude greater than the broadband signal determined from the predetermined function of the jamming frequency and increasing attenuation when the attenuated jamming signal effectively has a magnitude less than the broadband signal determined from a function of the jamming frequency.

53. The gain control method of claim 51, further comprising the steps of:
detecting the attenuated magnitude of the attenuated jamming signal;
detecting the magnitude of the broadband signal at a first frequency; and
comparing the magnitude of the attenuated, jamming signal and the broadband signal respectively in response to the previous detecting steps.
54. The gain control method of claim 53, wherein detecting the magnitude of the broadband signal at a first frequency comprises bandpass filtering.
55. The gain control method of claim 53, further comprising:
detecting the magnitude of the broadband signal at a second frequency; and
comparing the magnitude of the attenuated jamming signal with the broadband signal in response to the detected magnitude of the first and second frequencies;
wherein detecting the magnitude of the broadband signal at a first frequency comprises low frequency bandpass filtering; and
wherein detecting the magnitude of the broadband signal at a second frequency comprises high frequency bandpass filtering.
56. The gain control method of claim 55, further comprising the step of:
controlling variable attenuation in accordance with the jamming frequency using a predetermined function.
57. The gain control method of claim 56, further comprising the step of:
interpolating to determine the predetermined function, the interpolation performed between the results of comparing the attenuated jamming signal and the broadband signal and of comparing the attenuated jamming signal with the broadband signal at the first frequency.

58. The gain control method of claim 57, further comprising the step of:
storing the predetermined function.
59. The gain control method of claim 58, wherein the predetermined function is stored as a lookup table with values representing attenuation as a function of frequencies of the jamming oscillator.
60. The gain control method of claim 57, wherein the interpolation is a straight line interpolation.
61. The gain control method of claim 57, wherein the interpolation is a simple cable slope interpolation.
62. The gain control method of claim 51, further comprising the step of:
downloading from the headend a known characteristic curve representative of the attenuation over frequency of a transmission medium for the interdiction system.
63. The gain control method of claim 55, further comprising the step of:
curve fitting the ends of the known characteristic curve determined by the results of comparing the attenuated jamming signal and the broadband signal at the first frequency and of comparing the attenuated jamming signal with the broadband signal at the second frequency.
64. A television premium channel interdiction method for selectively jamming unauthorized premium programming transmitted from a headend to a subscriber on a broadband signal comprising the steps of:
assigning a particular interdiction device to at least one subscriber;
transmitting a plurality of channels on a broadband signal in the clear from the headend to a plurality of subscribers;
commanding an interdiction device in the interdiction system to jam a particular channel of the broadband signal;
oscillating at a fixed frequency;
oscillating at a variable frequency;

mixing the fixed frequency and the variable frequency; and
coupling the mixing of the fixed frequency and the variable frequency with the broadband signal to selectively jam the particular channel transmitted from the headend to the subscriber.
65. The television premium channel interdiction system according to claim 64, further comprising the step of:
commanding an interdiction device in the interdiction system to control the frequency of the variable frequency to selectively hop between particular frequencies to jam premium programming on the particular channel.
66. A television premium channel interdiction method for selectively jamming unauthorized premium programming transmitted from a headend to a subscriber on a broadband signal comprising the steps of:
assigning a particular interdiction device to at least one subscriber;
transmitting a plurality of channels on a broadband signal in the clear from the headend to a plurality of subscribers;
commanding an interdiction device in the interdiction system to jam a particular channel of the broadband signal;
generating a predetermined frequency;
mixing the broadband signal with the predetermined frequency so as to mix a certain channel of the broadband signal;
filtering the result of the mixing with a passband offset above or below the television band of the broadband signal;
generating a variable frequency;
mixing the result of the filtering with the variable frequency; and
combining the broadband signal with the result of the last mixing step so as to selectively jam a particular channel transmitted from the headend to a subscriber.
67. The television premium channel interdiction method of claim 66, further comprising the step of: commanding the generated variable frequency to selectably jam the particular channel.
68. A television premium channel interdiction method for selectively jamming unauthorized premium programming transmitted from a headend over a medium on a broadband signal comprising the steps of:
assigning a particular interdiction device to at least one subscriber;
transmitting a plurality of channels on a broadband signal in the clear from the headend to a plurality of subscribers;
commanding an interdiction device in the interdiction system to jam a particular channel of the broadband signal;
generating a jamming signal;
variably attenuating the jamming signal to produce an attenuated jamming signal;
combining the attenuated jamming signal with the broadband signal so as to selectively jam a particular channel transmitted from the headend to a subscriber;
comparing the magnitude of the attenuated jamming signal with the broadband signal; and
determining and providing control for the variable attenuation in accordance with a predetermined function of the jamming signal frequency.
69. The interdiction method according to claim 68, wherein control is provided by decreasing attenuation when the attenuated jamming signal effectively has a magnitude greater than the broadband signal determined from the predetermined function of the jamming frequency and increasing attenuation when the attenuated jamming signal effectively has a magnitude less than the broadband signal determined from a function of the jamming frequency.
70. The interdiction method of claim 68, further comprising the step of:
downloading the predetermined function from the headend.

71. The interdiction method of claim 68, further comprising the steps of:
detecting the attenuated magnitude of the attenuated jamming signal;
detecting the magnitude of the broadband signal at a first frequency;
comparing, responsive to the detection, the magnitude of the attenuated jamming signal and the broadband signal at the first frequency;
wherein said detection of the broadband signal magnitude at a first frequency comprises bandpass filtering;
detecting the magnitude of the broadband signal at a second frequency;
comparing the magnitude of the attenuated jamming signal with the broadband signal at the second frequency;
wherein said detection of the broadband signal at the first frequency further comprises low frequency bandpass filtering; and
wherein said detection of the broadband signal at the second frequency comprises high frequency bandpass filtering.
72. The interdiction system of claim 71, further comprising the step of:
interpolating to determine the predetermined function, the interpolation performed between the results of comparing the attenuated jamming signal and the broadband signal at the first frequency and of comparing the attenuated jamming signal and the broadband signal at the second frequency.
73. The interdiction system of claim 72, further comprising the step of:
storing the predetermined function.
74. The gain control method of claim 72, wherein the predetermined function is stored as a lookup table with values representing attenuation as a function of frequencies of the jamming oscillator.
75. The gain control method of claim 72, wherein the interpolation is a straight line interpolation.

76. The gain control method of claim 72, wherein the interpolation is a simple cable slope interpolation.
77. The television premium channel interdiction system of claim 68, wherein a frequency calibration routine to determine frequency calibration values or an attenuation calibration routine to determine the predetermined function are performed at periodic intervals during operation of the interdiction apparatus.
78. The television premium channel interdiction system of claim 77, wherein the frequency calibration values are previously stored by downloading from the headend.
79. The television premium channel interdiction system of claim 77, wherein the predetermined function is previously stored by downloading to the controller from the headend.
80. The television premium channel interdiction system of claim 77, wherein the periodic intervals are downloaded from the headend.
81. The gain control method of claim 68, further comprising the step of:
downloading from the headend a known characteristic curve for the medium representative of attenuation versus frequency.

82. The gain control method of claim 68, wherein the step of determining the predetermined function comprises:
curve fitting the ends of a known characteristic curve from the results of comparing the magnitude of the broadband signal at a first frequency and the magnitude of the broadband signal at a second frequency.