JPH04363923A - Method for preventing illegal viewing in subscription decoder - Google Patents

Abstract

PURPOSE:To prevent illegal viewing by using a received clock so as to improve in the unit of time of the paper viewing system onto a viewer. CONSTITUTION:Illegal viewing for a time longer than the specified time cannot be prevented since the time for the imposition in the unit of the time slows down when a clock frequency slows down in a conventional system that a clock from a crystal vibrator mounted externally is used and the charging in the unit of time by the paper view system is implemented. Then, a received bit stream in 2.048MHz supplied to a PN generating section 1 is supplied to a frequency divider 7, in which the frequency is divided, the frequency division signal is counted by a counter 3 to implement the charging in the unit of the time by the paper viewing system. Thus, the externally mounted crystal vibrator in a conventional system is replaced to prevent illegal viewing for a time longer than the specified time and even when the received clock is changed into other clock, since the PN generating section 1 is not in operation, scrambling cannot be decoded and the illegal viewing is prevented also in this case.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing unauthorized viewing in a pay decoder for preventing unauthorized viewing when a pay broadcast receiving decoder is used that descrambles received pay broadcasts.

0003

2. Description of the Related Art Charging systems for pay broadcasting such as pay satellite broadcasting include a flat system and a pay-per-view system. In the flat system, viewers contract in advance for the programs they want to watch, and the fee is the same. Furthermore, in the pay-per-view system (PPV), viewers apply to view programs for which they have not subscribed to a flat contract on the spot when the program is broadcast. The pay-per-view system further includes time-based charging (PPV/T) and program-based charging (PPV/P). In the pay-per-view system, the distinction between program-based charging and time-based charging, and the respective unit charging amounts are determined for each program.

[0004] In a program-based billing system, when an application is made to view a program, the viewing fee for that program is deducted. In addition, in the hourly billing system, when you apply for viewing, the viewing time is measured by a timer that divides the clock of a 12 MHz crystal oscillator externally attached to the security IC of the paid decoder, and the amount of money corresponding to this viewing time is calculated. is now being withdrawn.

FIG. 2 is a block diagram showing a circuit configuration of a time unit billing circuit block in a pay-per-view system of a conventional pay decoder. As shown in the figure, this circuit block includes a PN generator 1, a frequency divider 2, a counter 3, and a C
It has a PU 4 and a timer value setting section 5. PN generator 1
consists of a PLL and is supplied with a clock consisting of the received 2.048 MHz bit stream.
It is designed to operate only with a 48MHz clock. Further, the frequency divider 2 is supplied with a 12 MHz clock from an externally attached crystal oscillator (not shown).

In the pay-per-view hourly billing system, a 12 MHz clock from an external crystal oscillator is divided by a frequency divider 2, and this divided clock signal is counted by a counter 3. There is. More specifically, when a viewer subscribes to a program, a count value corresponding to the fee for the program is set as an initial value in the counter 3 by the CPU 4 via the timer value setting section 5. Then, the count value set in the counter 3 is subtracted by the frequency-divided clock signal from the frequency divider 2, that is, it counts down, and when the value of the counter 3 reaches 0, a signal is output to the CPU 4. , the amount per unit is debited. Note that the circuit block shown in FIG. 2 is configured in one package as a security IC.

[0007]

[Problems to be Solved by the Invention] The conventional paid decoders described above use the clock from an externally attached crystal oscillator to perform pay-per-view hourly billing. For example, if a viewer changes the clock frequency to one with a lower oscillation frequency and slows down the clock frequency, the hourly billing time will be delayed, allowing unauthorized viewing for a longer period of time than specified. There's a problem.

[0008] Furthermore, if an external crystal oscillator is built in,
Although it is thought that such a problem will disappear, incorporating this crystal oscillator in a circuit will result in poor stability, and it is difficult to incorporate it especially in parts where accuracy is required, such as billing.

The present invention has been made in view of the above, and
The purpose is to provide a method for preventing unauthorized viewing in a paid decoder that prevents unauthorized viewing due to pay-per-view hourly charging processing in paid broadcasting.

[Configuration of the invention]

[0011]

[Means for Solving the Problems] In order to achieve the above object, a method for preventing unauthorized viewing in a paid decoder of the present invention includes:
The gist of the present invention is to perform pay-per-view hourly charging using a clock received in a pay-TV receiving decoder that descrambles received pay-TV.

0012

[Operation] In the method for preventing unauthorized viewing in a paid decoder of the present invention, the received clock is used to perform hourly billing in a pay-per-view system.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the circuit configuration of a time unit billing circuit block in a pay-per-view system of a pay decoder that implements a method for preventing unauthorized viewing in a pay decoder according to an embodiment of the present invention. The circuit block shown in the figure divides a clock consisting of a received 2.048MHz bit stream instead of the frequency divider 2 which divides the clock of an external crystal oscillator in the conventional circuit shown in FIG. The difference is that the frequency divider 7 is provided, and the other configurations are the same.

The frequency divider 7 is supplied with the received 2.048 MHz clock in the same way as the PN generator 1, divides this clock, and supplies the divided clock to the counter 3. ing. From then on, the counter 3 is sent from the CPU 4 via the timer value setting section 5 in the same manner as described above.
The count value set as the initial value is subtracted by the divided clock from frequency divider 7, and when the value of counter 3 becomes 0, C
A signal is output to PU4, and the amount per unit is debited. It goes without saying that the frequency is divided by the frequency divider 7 to the same period as the frequency divided output of the frequency divider 2 which is supplied to the counter 3 in the circuit shown in FIG. 2 described above.

With this configuration, the frequency divider 7
is the same 2.048M that is supplied to PN generator 1
Since it is supplied with a 2.048 MHz clock, accurate operation is performed using this clock, eliminating the conventional unauthorized viewing, and in particular, since the PN generator 1 cannot operate unless the 2.048 MHz clock is used, it is possible to perform accurate operations using this clock. If the input line of the 048MHz clock is cut off and another clock is input, the PN generator 1 will not operate and will not be able to descramble, so it is possible to prevent unauthorized viewing in this case as well. can. In other words, since an externally attached crystal oscillator is not used like in the past, the crystal oscillator is replaced with one with a slower oscillation frequency, and the counter 3
This eliminates the problem of the counting operation becoming slow and unauthorized viewing taking place for a longer time than specified.

[0017]

[Effects of the Invention] As explained above, according to the present invention,
Since the received clock is used for pay-per-view hourly billing, the conventional external crystal oscillator can be replaced with a different one to prevent unauthorized viewing for a longer time than specified. In addition, if the received clock is changed to another clock, the PN generator does not operate and therefore cannot be descrambled, making it possible to prevent unauthorized viewing in this case as well.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a circuit configuration of a charging circuit block in units of time in a pay-per-view system of a pay decoder that implements a method for preventing unauthorized viewing in a pay decoder according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional circuit configuration.

[Explanation of symbols]

1 PN generation part 3 Counter 4 CPU 7 Frequency divider

Claims (1)

[Claims] 1. A method for preventing unauthorized viewing in a pay-per-view decoder, which performs pay-per-view hourly charging using a clock received in a pay-per-view receiving decoder that descrambles received pay-per-view broadcasts.