Variable frequency CATV jamming method and apparatus

A method for controlling the reception of selected television channels by individual subscribers in a cable television, or CATV system, which selected television channels are individually referred to as channel z, wherein channel z has a television channel's signal, and a unique carrier wave onto which the television signal is modulated, which is the carrier wave of that television signal, and which carrier wave has a unique carrier wave frequency, and wherein said television signal has a regularly spaced horizontal synchronization signal and a regularly spaced vertical synchronization signal, comprised of the following steps:

• (A) selecting and generating a reference frequency for each of the channels "z", which is stable in frequency amplitude, wherein the reference frequency is a suitable frequency to jam channel z;
• (B) using a generating means to generate a frequency the amplitude of which is greater by a selected amount, than each of the amplitudes of each of the frequencies of each of the carrier waves of each of the television signals of each channel z;
• (C) sending a frequency generation signal to the generating means, which causes the generating means to generate a jamming frequency that corresponds to the carrier wave frequency of a selected television channel's signal, and of a slightly greater amplitude;
• (D) comparing the jamming frequency to the reference frequency, and if the jamming frequency is higher or lower than the reference frequency, sending a different frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by an initial amount, to the generating means, causing the generating means to generate a new jamming frequency, then again comparing the jamming frequency with the reference frequency, and if the jamming frequency is higher or lower than the reference frequency, sending a new frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by half of the previous amount, to the generating means, causing it to generate a new jamming frequency, which is again compared to the reference frequency, until:
• (i) the last increase or decrease in the frequency of the jamming frequency is less than a fixed predetermined frequency value, such that the sum frequency of the jamming frequency plus the fixed predetermined frequency value would also be a correct frequency to jam channel z, and
• (ii) the second last increase or decrease in the frequency of the jamming frequency was less than the fixed predetermined frequency value, and
• (iii) the second last increase or decrease in the frequency of the jamming frequency was the opposite of the last increase or decrease in the jamming frequency;
• (E) remembering whichever of the last and second last frequency generating signal's resulted in the jamming frequency being greater than the reference frequency, as a channel z frequency generating signal, wherein the channel z frequency generating signal is the frequency generating signal that causes the generating means to generate a jamming frequency that will jam channel z, wherein the jamming frequency that will jam channel z is called the channel z jamming frequency;
• (F) continuing steps (D) and (E), until there is remembered a channel z frequency generating signal for each channel z, and then suspending steps (D) and (E);
• (G) In continuous rotation, each for durations suitable for jamming the horizontal synchronization signal, combining the channel z jamming frequency with the television channels' signals being transmitted to subscribers who are not entitled to receive the television signal which the channel z jamming frequency is jamming;
• and
• (H) Where "T" is a number to be selected, after every T minutes, suspending step (G) for a period long enough for steps (D) to (F) to be repeated, repeating steps (D) to (F), and then resuming step (G).

An apparatus for generating and controlling the application of N jamming signals to individual subscribers' lines in a cable television, or CATV system which is offering at least N channels that are individually referred to as channel z, wherein channel z has a television channel's signal, and a unique carrier wave onto which the television signal is modulated, which is the carrier wave of that television signal, and which carrier wave has a unique carrier wave frequency, and wherein said television signal has a regularly spaced horizontal synchronization signal and a regularly spaced vertical synchronization signal, comprised of:

• (A) a voltage controlled oscillator for generating, one at a time, a number of different frequencies, each of which is generally referred to as a jamming frequency, wherein the amplitude of each jamming frequency, is greater, by a selected amount, than each of the amplitudes of each of the frequencies of each of the carrier waves of each of the television signals of each channel z;
• (B) a set of subscriber jamming signal switches, each of which receives the jamming frequency, and each of which will transmit the jamming frequency to the subscriber's line to which that subscriber's jamming signal switch is connected, when that subscriber's jamming signal switch is closed;
• (C) a reference frequency generating means that generates a stable reference frequency;
• (D) a comparison means that receives the jamming frequency, and that receives the referency frequency, and that can divide the jamming frequency by a dividing factor, wherein the dividing factor is such that when the result of the jamming frequency divided by the dividing factor equals the reference frequency, the jamming frequency is a frequency suitable for jamming channel z, and wherein the comparison means can compare the referency frequency to the result of the jamming frequency divided by the dividing factor, and determine if the referency frequency is greater than or less than the result of the jamming frequency divided by the dividing factor, and which comparison means can output the results of the comparison;
• and
• (E) a service control center that receives information from the CATV system on which subscribers are entitled to receive which television signals;
• and which outputs a frequency generating signal to the voltage controlled oscillator, that determines the frequency of the jamming frequency, and which service control center, based on the information it receives from the CATV system, as to the frequencies of the carrier waves of each of channels z, determines the dividing factor that the comparison means must divide the jamming frequency by, so that if the result of the jamming frequency divided by the dividing factor equals the reference frequency, the jamming frequency will be the appropriate frequency for jamming the television signal of channel z, and which starts the system by beginning the testing by sending a frequency generating signal to the voltage controlled oscillator, causing the voltage controlled oscillator to generate a jamming frequency, and then sending the value of the dividing factor, to the comparison means, and then receiving from the comparison means, a first signal if the comparison resulted in the result of the jamming frequency divided by the dividing factor being greater than the reference frequency, and a second signal if the comparison resulted in the result of the jamming frequency divided by the dividing factor being less than the reference frequency, and if the result of the jamming frequency divided by the dividing factor is higher or lower than the referency frequency, sending a different frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by an initial amount, to the voltage controlled oscillator, causing it to generate a different jamming frequency, then, when the service control center receives the result of the new comparison from the comparison means, if the result of the jamming frequency divided by the dividing factor is higher or lower than the reference frequency, again sending a different frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by less than the previous increase or decrease, to the voltage controlled oscillator, then again receiving the results of the comparison of the result of the jamming frequency divided by the dividing factor being compared to the reference frequency, and continuing to receive the results of the comparison and to send out different frequency generating signals, until the last increase or decrease in the frequency of the jamming frequency was less than a predetermined frequency value, which predetermined frequency value is such that the product of the reference frequency multiplied by the dividing factor, plus the predetermined frequency value, is a correct frequency to jam channel z, and then the service control center stores the last frequency generating signal, as a channel z frequency generating signal, wherein a channel z frequency generating signal is the frequency generating signal that causes the generating means to generate a jamming frequency that will jam channel z, wherein the jamming frequency that will jam channel z is called the channel z jamming frequency, and the service control center continues the above series of operations until there is stored a channel z frequency generating signal for each of the channels to be jammed, and once all of the channel z frequency generating signals have been stored the testing is ended, then the service control center suspends the operation of testing and begins the jamming by sending, in continuous rotation, each for durations of approximately 6 to 10 .mu.S, each of the channel z frequency generating signals to the voltage controlled oscillator, and closing each of the subscriber jamming signal switches to the subscribers' lines who are not entitled to receive the television signal of channel z, when the channel z jamming frequency is being generated by the voltage controlled oscillator, and opening the Jamming signal switches of those subscribers who are entitled to receive channel z, then, after a pre-determined period of time the service control center suspends the jamming for a period of time long enough for the testing to be performed, and again performs the testing, and then again suspends the testing and again resumes the jamming, and continues to alternate between the testing and the jamming, at predetermined periods of time.

An apparatus for generating and controlling the application of N jamming signals to individual subscribers' lines in a cable television, or CATV system which is offering at least N channels that are individually referred to as channel z, wherein channel z has a television channel's signal, and a unique carrier wave onto which the television signal is modulated, which is the carrier wave of that television signal, and which carrier wave has a unique carrier wave frequency, and wherein said television signal has a regularly spaced horizontal synchronization signal and a regularly spaced vertical synchronization signal, comprised of:

• (A) a voltage controlled oscillator for generating, one at a time, a number of different frequencies, each of which is generally referred to as a jamming frequency, wherein the amplitude of each jamming frequency is greater, by a selected amount, than each of the amplitudes of each of the frequencies of each of the carrier waves of each of the television signals of each channel z;
• (B) a set of subscriber jamming signal switches, each of which receives the jamming frequency, and each of which will transmit the jamming frequency to the subscriber's line to which that subscriber's jamming signal switch is connected, when that subscriber's jamming signal switch is closed;
• (C) a reference frequency generating means that generates a reference frequency, which is stable in frequency;
• (D) a comparison means that receives the jamming frequency, and that receives the reference frequency, and that can divide the jamming frequency by a dividing factor, wherein the dividing factor is a factor such that when the result of the jamming frequency divided by the dividing factor equals the reference frequency, the jamming frequency is a frequency suitable for jamming channel z, and wherein the comparison means can compare the reference frequency to the result of the jamming frequency divided by the dividing factor, and determine if the reference frequency is greater than or less than the result of the jamming frequency divided by the dividing factor, and which comparison means can output the results of the comparison;
• and
• (E) a service control center that receives information from the CATV system on which subscribers are entitled to receive which television signals;
• and which outputs a frequency generating signal to the voltage controlled oscillator, that determines the frequency of the jamming frequency, and which, based on the information it receives from the CATV system, as to the frequencies of the carrier waves of each of channels z, determines the value of the dividing factor that the comparison means must divide the jamming frequency by, so that if the result of the jamming frequency divided by the dividing factor equals the reference frequency, the jamming frequency will be the appropriate frequency for jamming the television signal of channel z, and which starts the system by beginning testing by sending a frequency generating signal to the voltage controlled oscillator, causing it to generate a jamming frequency, and then sending the appropriate information on the value of the dividing factor, to the comparison means, and the receiving from the comparison means, a first signal if the comparison resulted in the result of the jamming signal divided by the dividing factor being greater than the reference frequency, and a second signal if the comparison resulted in the result of the jamming signal divided by the dividing factor being less than the reference frequency, and if the result of dividing the jamming frequency by the dividing factor is higher or lower than the reference frequency, sending a different frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by an initial amount, to the voltage controlled oscillator, causing it to generate a different jamming frequency, then, when the service control center receives the result of the new comparison from the comparison means, if the result of the jamming frequency divided by the dividing factor is higher or lower than the reference frequency, again sending a different frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by half of the previous increase or decrease, to the voltage controlled oscillator, then again receiving the results of the comparison of the result of the jamming frequency divided by the dividing factor being compared to the reference frequency, and continuing to receive the results of the comparison and to send out different frequency generating signals, until:
• (i) the last increase or decrease in the frequency of the jamming frequency was less than a predetermined frequency value, which predetermined frequency value is such that the product of the reference frequency multiplied by the dividing factor, plus the predetermined frequency value, is a correct frequency to jam channel z, and
• (ii) the second last increase or decrease in the frequency of the jamming frequency was less than the predetermined frequency value, and
• (iii) the second last increase or decrease in the frequency of the jamming frequency was the opposite of the last increase or decrease in the jamming frequency, then the service control center stores whichever of the last and second last frequency generating signals resulted in, the result of the jamming frequency divided by the dividing factor being greater than the reference frequency as the channel z frequency generating signal, wherein the channel z frequency generating signal is the frequency generating signal that causes the generating means to generate a jamming frequency that will jam channel z, wherein the jamming frequency that will jam channel z is called the channel z jamming frequency and the service control center continues the above series of operations until there is stored a channel z frequency generating signal for each of the channels to be jammed, and once all of the channel z frequency generating signals have been stored the testing is ended, then the service control center suspends the operations of testing and begins the jamming by sending, in continuous rotation, for durations of approximately 6 to 10 .mu.S, each of the channel z frequency generating signals to the voltage controlled oscillator, and closing each of the subscriber jamming signal switches to the subscribers' lines who are not entitled to receive the television signal of channel z, when the channel z jamming frequency is being generated by the voltage controlled oscillator, and opening the jamming signal switches of those subscribers who are entitled to receive channel z, then, after a predetermined period of time the service control center suspends the jamming for a period of time long enough for the testing to be performed, and again performs the testing, and then again suspends the testing and again resumes the jamming, and continues to alternate between the testing and the jamming, at predetermined periods of time.

A method for controlling the reception of selected television channels by individual subscribers in a cable television, or CATV system, which selected television channels are individually referred to as channel z, wherein channel z has a television channel's signal, and a unique carrier wave onto which the television signal is modulated, which is the carrier wave of that television signal, and which carrier wave has a unique carrier wave frequency, and wherein said television signal has a regularly spaced horizontal synchronization signal and a regularly spaced vertical synchronization signal, comprised of:

• (A) Generating a reference frequency;
• (B) sending an initial frequency generation signal to a generating means, which causes the generating means to generate a jamming frequency that is stable in frequency and with an amplitude, that is greater, by a selected amount, than each of the amplitudes of each of the frequencies of each of the carrier waves of each of the television signals of each channel z;
• (C) dividing the jamming frequency by a dividing factor such that the jamming frequency will have a frequency suitable for jamming channel z when the result of the jamming frequency divided by the dividing factor equals the reference frequency, and then comparing, the result of the jamming frequency divided by the dividing factor to the reference frequency and if the result of the jamming frequency divided by the dividing factor is higher or lower in frequency than the reference frequency sending a different frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by an initial amount, to the generating means, causing it to generate a new jamming frequency, then again comparing the generated jamming frequency, divided the dividing factor by, with the reference frequency, and if the result of dividing the jamming frequency by the dividing factor is higher or lower than the reference frequency, sending a new frequency generating signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generating signal, by less than the previous amount, to the generating means, causing it to generate a new jamming frequency, which, divided by the dividing factor, is again compared to the reference frequency, until the last increase or decrease in the frequency of the jamming frequency was less than a predetermined frequency value, which predetermined frequency value is such that if the jamming frequency would jam channel z, then the jamming frequency plus the predetermined frequency value would also jam channel z, and then storing the last frequency generating signal, as a channel z frequency generating signal, wherein the channel z frequency generating signal is the frequency generating signal that causes the generating means to generate a jamming frequency that will jam channel z, wherein the jamming frequency that will jam channel z is called the channel z jamming frequency;
• (D) continuing steps (B) and (C) until there is a stored channel z frequency generating signal for each channel z, and then suspending steps (B) and (C);
• (E) after step (D), in continuous rotation, each for durations of approximately 6 to 10 .mu.S, combining the channel z jamming frequency with the television channels' signals being transmitted to subscribers who are not entitled to receive the television signal which channel z jamming signal is jamming;
• and
• (F) after each period of T minutes suspending step (E) for a period of time for a period long enough for steps (B), (C), and (D) to be performed, performing said steps, and then resuming step (E).

A method for controlling the reception of selected television channels by individual subscribers in a cable television, or CATV system, which selected television channels are individually referred to as channel z, wherein channel z has a television channel's signal, and a unique carrier wave onto which the television signal is modulated, which is the carrier wave of that television signal, and which carrier wave has a unique carrier wave frequency, and wherein said television signal has a regularly spaced horizontal synchronization signal and a regularly spaced vertical synchronization signal, comprised of the following steps:

• (A) generating a reference frequency;
• (B) sending a frequency generation signal to a generating means, which causes the generating means to generate a jamming frequency that is stable in frequency, and with an amplitude that is greater by a selected amount than each of the amplitudes of each of the frequencies of each of the carrier waves of each of the television signals of each channel z;
• (C) dividing the jamming frequency by a dividing factor having a value such that the jamming frequency will be suitable for jamming channel z when the result of dividing the jamming frequency by the dividing factor equals the reference frequency, and then comparing the result of dividing the jamming frequency by the dividing factor to the reference frequency, and if the result, is higher or lower in frequency than the reference frequency sending a different frequency generation signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generation signal, by an initial amount, to the generating means, causing it to generate a new jamming frequency, then again comparing the result of dividing the jamming frequency by the dividing factor, to the reference frequency, and if the result is higher or lower than the reference frequency, sending a new frequency generation signal, which is either lower in voltage or higher in voltage, respectively, than the previous frequency generation signal, by half of the previous amount, to the generating means, causing it to generate a new jamming frequency, and again comparing the result of dividing the jamming frequency by the dividing factor, with the reference frequency, until:
• (a) the last increase or decrease in the frequency of the jamming frequency was less than a predetermined frequency value, where the predetermined frequency value was such that if the jamming frequency would jam channel z, then the sum frequency of the jamming frequency plus the predetermined frequency would also jam channel z, and
• (b) the second last increase or decrease in the frequency of the jamming frequency was less than the predetermined frequency value, and
• (c) the second last increase or decrease in the frequency of the jamming frequency was the opposite of the last increase or decrease in the jamming frequency, then storing whichever of the last and second last frequency generation signals resulted in the result of dividing the jamming frequency by the dividing factor being greater than the reference frequency, as a channel z frequency generating signal, wherein a channel z frequency generating signal is the frequency generation signal that causes the generating means to generate a jamming frequency that will jam channel z, wherein the jamming frequency that will jam channel z is called the channel z jamming frequency;
• (D) continuing step (C) until there is a stored channel z frequency generating signal for each channel z, and then suspending step (C);
• (E) after step (D), in continuous rotation, each for durations of approximately 6 to 10 .mu.S, combining the channel z jamming frequency with the television channels' signals being transmitted to subscribers who are not entitled to receive the television signal which the channel z jamming frequency is jamming;
• and
• (F) after each period of T minutes suspending step (E) for a period of time long enough for steps (C) and (D) to be performed, performing said steps, and then resuming step (E).

An apparatus for controlling the reception of selected television channels by individual subscribers in a cable television, or CATV system, which selected television channels are individually referred to as channel z, wherein channel z has a television channel's signal, and a unique carrier wave onto which the television signal is modulated, which is the carrier wave of that television signal, and which carrier wave has a unique carrier wave frequency, and wherein said television signal has a regularly spaced horizontal synchronization signal and a regularly spaced vertical synchronization signal, comprised of:

• (A) a voltage controlled oscillator for generating, one at a time, a number of different frequencies, each of which is generally referred to as a jamming frequency and each of which is of a greater amplitude, by a selected amount, than each of the amplitudes of each of the frequencies of each of the carrier waves of each of the television signals of each channel z;
• (B) a set of subscriber jamming signal switches, each of which receives the jamming frequency, and each of which will transmit the jamming frequency to the subscriber's line to which that subscriber's jamming signal switch is connected, when that subscriber's jamming signal switch is closed;
• (C) a Quartz crystal reference frequency generating means that generates a reference frequency, which is stable in frequency;
• (D) a frequency comparator circuit that receives the jamming frequency and that receives the reference frequency and can divide the jamming frequency by a dividing factor, wherein when the result of the jamming frequency divided by the dividing factor equals the reference frequency, then the jamming frequency is a correct frequency to jam the horizontal synchronization signal of channel z, and which frequency comparator circuit can compare the result of dividing the jamming frequency by the dividing factor, to the reference frequency and determine if one is greater than the other;
• (E) an integrator that receives the result from the frequency comparator circuit and averages it to produce a first signal if the result of dividing the jamming frequency by the dividing factor is greater than the reference frequency, and produces a second signal if the result of dividing the jamming frequency by the dividing factor is less than the reference frequency;
• (F) a digital to analog converter which outputs, one at a time, a variety of different analog voltages, in response to digital signals that are inputted to it;
• and
• (G) a service control center that receives information from the CATV system on which subscribers are entitled to receive which television signals;
• and which begins the testing by outputting a digital code that represents a signal to the digital to analog converter, which converts the digital code that represents a signal into an analog frequency generating signal which the digital to analog converter sends to the voltage controlled oscillator, resulting in the voltage controlled oscillator outputting a jamming frequency, then the service control center, based on the information that the service control center receives from the head end as to the frequencies of the channels to be jammed, determines the value of the dividing factor, the service control center then sends the information of what value the dividing factor should be to the frequency comparator circuit, the service control center then receives a first signal from the integrator if the comparison in the frequency comparator circuit determined that the result of the jamming frequency divided by the dividing factor was greater than the reference frequency, and a second signal if the comparison determined that the result of dividing the jamming frequency by the dividing factor was less than the reference frequency, if the result of dividing the jamming frequency by the dividing factor is higher or lower than the reference frequency, the service control center sends a different digital code that represents a signal, which will result in a jamming frequency that is either lower in frequency or higher in frequency, than the previous jamming frequency, by an initial amount, then when the service control center receives the result of the new comparison, if the result of dividing the jamming frequency by the dividing factor is higher or lower than the reference frequency, the service control center sends a different digitial code that represents a signal, which will result in a jamming frequency that is either lower in frequency or higher in frequency, than the previous jamming frequency, by less than the previous increase or decrease, until the last increase or decrease in the frequency of the jamming frequency was less than a predetermined frequency value, such that if the jamming frequency would be a correct frequency to jam channel z, then the sum frequency of the jamming frequency plus the predetermined frequency value would also be a correct frequency to jam channel z, such that if JFz would be a correct frequency to jam channel z, JFa+I would also be a correct frequency to jam channel z], at which time the service control center stores the last digital code that represents a signal, as the channel z digital code wherein the channel z digital code is the digital code that represents a signal that results in the voltage controlled oscillator generating a jamming frequency that will jam channel z, wherein the jamming frequency that will jam channel z is called the channel z jamming frequency, the service control center continues to operate as stated until there is a stored channel z digital code for each of the channels to be jammed, then the service control center suspends the operations of the testing and begins the jamming by sending, in continuous rotation, each for durations of between approximately 6 and 10 .mu.S, each of the channel z digital codes to the voltage controlled oscillator, and closing each of the subscriber jamming signal switches to the subscribers who are not entitled to receive the television signal of channel z, when the channel z digital code is being sent to the voltage controlled oscillator, and opening the jamming signal switches of those subscribers who are entitled to receive channel z, when the channel z digital code is being sent to the voltage controlled oscillator, then after a predetermined period of time T1 the service control center suspends the jamming for a period of time T2, which is long enough for the testing to be performed, and the service control center again performs the testing, and then the service control center again suspends the testing for a period of time T1, and again resumes the jamming for period T2, and continues to alternate between the testing and the jamming, during periods T2 and T1, respectively.

An apparatus for controlling the reception of selected television channels by individual subscribers in a cable television, or CATV system, which selected television channels are individually referred to as channel z, wherein channel z has a television channel's signal, and a unique carrier wave onto which the television signal is modulated, which is the carrier wave of that television signal, and which carrier wave has a unique carrier wave frequency, and wherein said television signal has a regularly spaced horizontal synchronization signal and a regularly spaced vertical synchronization signal, comprised of:

• (A) a voltage controlled oscillator for generating, one at a time, a number of different frequencies, each of which is generally referred to as a jamming frequency") and each of which is of a greater amplitude, by a selected amount, than each of the amplitudes of each of the frequencies of each of the carrier waves of each of the television signals of each channel z;
• (B) a set of subscriber jamming signal switches, each of which receives the jamming frequency, and each of which will transmit the jamming frequency to the subscriber's line to which that subscriber's jamming signal switch is connected, when that subscriber's jamming signal switch is closed;
• (C) a Quartz crystal reference frequency generating means that generates a reference frequency, which is stable in frequency;
• (D) a frequency comparator circuit that receives the jamming frequency and that receives the reference frequency and can divide the jamming frequency by a dividing factor, wherein when the result of the jamming frequency divided by the dividing factor equals the reference frequency, then the jamming frequency is a correct frequency to jam the horizontal synchronization signal of channel z, and which frequency comparator circuit can compare the result of the jamming frequency divided by the dividing factor to the reference frequency and determine if one is greater than the other;
• (E) an integrator that receives result from the frequency comparator circuit and averages it to produce a first signal if the result of the jamming frequency divided by the dividing factor is greater than the reference frequency, and produces a second signal if the result of the jamming frequency divided by the dividing factor is less than the reference frequency;
• (F) a digital to analog converter which outputs, one at a time, a variety of different analog voltages, in response to digital signals that are inputted to it;
• and
• (G) a service control center that receives information from the CATV system on which subscribers are entitled to receive which television signals;
• and which begins the testing by outputting a digital code that represents a signal to the digital to analog converter, which converts it into an analog frequency generating signal ("FGSa") which it sends to the voltage controlled oscillator, resulting in the voltage controlled oscillator outputting a jamming frequency, then the service control center, based on the information it receives from the head end as to the frequencies of the channels to be jammed, determines the value of the dividing factor, the service control center then sends the information of what value the dividing factor should be to the frequency comparator circuit, the service control center then receives a first signal from the integrator if the comparison in the frequency comparator circuit resulted in the result of the jamming frequency divided by the dividing factor being greater than the reference frequency, and a second signal if the comparison resulted in the result of the jamming frequency divided by the dividing factor being less than the reference frequency, if the result of the jamming frequency divided by the dividing factor is higher or lower than the reference frequency, the service control center sends a different digital code that represents a signal, which will result in a jamming frequency that is either lower in frequency or higher in frequency, than the previous jamming frequency, by an initial amount, then when the service control center receives the result of the new comparison, if the result of the jamming frequency divided by the dividing factor is higher or lower than the reference frequency, the service control center sends a different digital code that represents a signal, which will result in a jamming frequency that is either lower in frequency or higher in frequency, than the previous jamming frequency, by half of the previous increase or decrease, until:
• (a) the last increase or decrease in the frequency of the jamming frequency was less than a fixed predetermined frequency value, such that if the channel z jamming frequency would be a correct frequency to jam channel z, then the channel z jamming frequency plus the fixed predetermined frequency value would also be a correct frequency to jam channel z;
• and
• (b) the second last increase or decrease in the frequency of the jamming frequency was less than the predetermined frequency value, and
• (c) the second last increase or decrease in the frequency of the jamming frequency was the opposite of the last increase or decrease in the jamming frequency, at which time the service control center stores whichever of the last and second last DCSa's resulted in the result of the jamming frequency divided by the dividing factor being greater than the reference frequency, as, the channel z digital code wherein the channel z digital code is the digital code that represents a signal that results in the voltage controlled oscillator generating a jamming frequency that will jam channel z, wherein the jamming frequency that will jam channel z is called channel z jamming frequency, the service control center continues to operate as stated until there is a stored channel z digital code for each of the channels to be jammed, then the service control center suspends the operations of testing and begins jamming by sending, in continuous rotation, each for durations of between approximately 6 and 10 .mu.S, each of the channel z digital codes to the voltage controlled oscillator, and closing each of the subscriber jamming signal switches to the subscribers who are not entitled to receive the television signal of channel z, when the channel z digital code is being sent to the voltage controlled oscillator, and opening the jamming signal switches of those subscribers who are entitled to receive channel z, when the channel z digital code is being sent to the voltage controlled oscillator, then after a pre-determined period of time T1 the service control center suspends the jamming for a period of time T2, which is long enough for the testing to be performed, and the service control center again performs the testing, and then the service control center again suspends the testing for a period of time T1, and again resumes the jamming for period T2, and continues to alternate between the testing and the jamming, during periods T2 and T1, respectively.