JPH0570983B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a billing method that can be used in a unidirectional signal transmission and reception system such as satellite broadcasting. Conventional configuration and its problems In a unidirectional signal transmission/reception system such as satellite broadcasting, in order to operate the terminal receiver in the same way as when receiving CATV pay programs, the viewing fee must be paid in a deferred manner. It is necessary to make the viewer pay, and if the viewer does not pay, it is necessary to make the viewer's terminal inoperable. These are implemented in pay television in interactive CATV systems. However, in the case of the CATV system, the system requires the transmitting side to request viewing of pay TV via uplink or telephone, so this cannot be used for a one-way system such as satellite broadcasting. Furthermore, when a large number of subscribers applied to the sending side all at once, the capacity of the telephone line and the receiving processing capacity of the sending side were exceeded. An example of the configuration of such a conventional example is shown in FIG. In the figure, 1 is the center computer of the CATV station, which manages the subscriber's viewing fee payment status, the specification of broadcast programs according to the subscriber's wishes, the creation of control codes, etc.
The control code is added to a video signal from a studio or the like and sent out. 3A is the head end,
For example, multiple video signals from CATV center 2 are
Transmit in line with VHF mid-band. 3B is a buffer circuit that receives upstream signals from each terminal, and the head end 3A, the tuner/converter 4 on the terminal side of the CATV, and the buffer circuit 3B are connected by the same cable or another cable. Further, a telephone line may be used instead of the cable from the tuner/converter 4 to the buffer circuit 3B. This tuner/converter 4 converts the mid-band signal into one channel (or two channels) of VHF.
This is a tuner or converter on the terminal side that converts one channel of a mid-band CATV signal into one channel of VHF according to a command from the keypad 5. Note that if the CATV signal is scrambled, it may be converted to a baseband signal, descrambled, and then converted back to an RF signal and output as a VHF 1-channel signal. 6 is a television receiver that receives normal VHF band reception. The viewer operates the keypad 5 or uses the telephone 7.
Apply for the program you want to watch (charged) to the center computer 1 via . At Center 1, charges are set for each terminal and if scrambled,
Insert the decryption key code into the center computer 1 →
Send it in the order of CATV center 2 → head end 3 → tuner/converter 4, descramble it using this key code in tuner/converter 4, play back the normal image NTSC video signal, and convert it to 1 channel of VHF. and supplies it to the television receiver 6. There are a large number of tuners/converters 4 to telephones 7, and a telephone office is interposed between the telephones 7 and the telephone interface 8. The telephone interface 8 is generally operated by a human being who listens to requests from each terminal and converts them into input form for the center computer 1. This is an example. OBJECTS OF THE INVENTION An object of the present invention is to provide a billing method that can realize a pay television system in a unidirectional signal transmission system such as a satellite broadcasting system. Structure of the Invention In the present invention, a one-way television signal receiving device receives billing information corresponding to the time of viewing a television program and the content of the program at regular intervals in the form of a digital signal. A billing amount determination circuit in the receiving device determines and stores the amount, and charge data proportional to the amount is read out and displayed as necessary. In that case, a nonvolatile memory for storing fee information and a nonvolatile memory for storing a key code signal for decoding the encrypted video signal and audio signal are separately provided. The key code signal memory includes a first memory that stores the currently valid key code K _T and a second memory that stores the key code K _T+1 signal that will be valid in the future. Key code signals continuously sent from a sending side are written into a nonvolatile memory only once. Furthermore, a non-volatile memory is provided to store a flag indicating the date and month when the contents of the charge information memory were rewritten with the charge information for each terminal sent from the sending side, and the type of charge information at that time. A third memory is provided which stores information that the contents of the second memory have been transferred to the first memory in response to the key code signal switching signal. DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 2 shows an embodiment of the present invention. 11 in the figure is a satellite broadcasting transmission center, which is called a DBS center. 12 is a large parabolic antenna that sends signals to a geostationary satellite 13. 13 is a geostationary satellite, which is a broadcasting satellite that relays signals sent from the ground and retransmits them to the ground. 1
4 is a receiving antenna installed on the ground. 1
5 is a low noise converter, for example, antenna 1
The 12 GHz band signal received by 4 is converted to 1 GHz band and transmitted to the receiver 16. 19 of the receivers 16 is called an intermediate frequency demodulation unit (IDU), and for example, it converts the 1GHz band input to 400M
It is converted to the second IF of Hz, amplified, detected, and outputs a baseband signal. 20 is a data processing circuit that extracts the output digital signal, processes it, and supplies it to the descrambler 21. Assume now that the video signal is scrambled using a method of synchronizing shift and randomly inverting the video components, and the audio is scrambled using a method of randomly changing the bit arrangement using digital audio. If the output of the IDU 19 is projected as it is on the CRT of the color television receiver 17, the brightness of the screen will be reversed and horizontal and vertical synchronization cannot be achieved, so the content will be blurred and the content will not be clear. Also, if you listen to the voice as it is from the speaker, it becomes noise. Therefore, the descrambler 21 switches between inverting and non-inverting the video according to the output of the data processing circuit 20, and rearranges each bit of the audio digital signal to restore normal video and audio (descramble). do. A/
The V regeneration circuit 22 changes the DC level only during the horizontal retrace period during the output of the IDU ₁₉ , that is, the portion from t ₁ to _{t 2} in FIG. _-t11 to reproduce the original video signal (FIG. 3A), and convert the digital audio signal output from the descrambler 21 into an analog audio signal. The output of this A/V regeneration circuit 22 is transmitted to the RF modulator 2.
Step 3 converts the signal to an appropriate channel in the VHF band,
If the output is supplied to the antenna input of an ordinary color television receiver 17, the scrambled video and audio can be viewed in their normal, descrambled state. There is often a charge for viewing such scrambled video and audio back to normal images and sounds. If there is a charge, the charge is indicated by a control digital signal superimposed on the vertical blanking period (VBL) of the video signal of the program, and the charge is recorded in the memory within the receiver. Generally, if you receive a certain program for more than 2 to 10 minutes, you are often required to pay for the entire program. To pay the fee, for example, add a card reader to the data processing circuit 20 in Figure 2, insert the purchased card (such as a number of rolls) into the card, and check the amount paid. There is a method of sending a descrambling control signal from the data processing circuit 20 to the descrambler 21 only for a time corresponding to the amount of time. Alternatively, you can pay the fee in advance to the bank 18 and use the prepaid fee as data.
A code representing the paid fee is sent from the DBS center 11 to each terminal (individually assigned an address) via the geostationary satellite 13, and the fee code is written in the memory of the terminal. Change (decrease) the rate code in
When the number reaches "0", there is also a method in which the money is paid to the bank 18 again and the above procedure is repeated. Now, here, the data processing circuit 20 in FIG.
The contents of the video signal are configured as shown in 31 to 50 in Figure 4, and when a pay program is received, the video signal is
According to the charge data superimposed on the VBL period, charges according to the viewing time are written to non-volatile memory, the viewing charges are paid to the bank every month, and the paid charges are polled from the DBS center 11 for each terminal (each address). and send it out to reduce the contents of memory 47,
The system is such that, unless the contents of the memory 47 become "0", the paid programs cannot be viewed from the next month. In Figure 4, 31 is the VBL output from IDU19.
This is a binarization circuit for shaping the waveform of a binary data signal superimposed on a period to form a pulse waveform as shown in the left end portion of FIG. 5B. 32 is a clock detection circuit, which uses the clock run signal CR (Clock Run), which is a repetition of the 2-byte "1" and "0" signals at the beginning of FIG. A framing code is detected at the 8th bit of the framing code signal FC in B, establishing frame synchronization, and the sampling clock generated by the sampling clock generating circuit 33 is synchronized with the received signal B. 33 is a circuit that forms a sampling clock with an appropriate phase controlled in this manner, and the output thereof is divided by a main clock generation circuit 34 and then outputted to the work RAM 3.
7. Forms a main clock that drives the work ROM 38, center processing unit (CPU) 39, etc. A clock synchronized with each bit of the received signal shown in FIG. If the pulse width of each bit of the received signal B is 5/8f _sc , it will be approximately 175 ns, and at this period, the work RAM 37 in Fig. 4
~CPU 39 is difficult to operate. or,
When an 8-bit microprocessor is used as the CPU 39, it is more convenient to handle the received data as an 8-bit parallel signal. Therefore, a serial input/parallel output type shift register such as SN74LS164 is suitable as the sampling circuit 35. If the output is stored bit by bit in the latch circuit 36 using the 8th bit of the framing code as a reference, the output will change in 8 bits in parallel at a period of 8×5/8 f _sc =1.4 μs. This cycle is suitable for the operation of each circuit. Its output is connected to bus line 40. 37 is CPU 39's worm RAM, 38A, 38
B is a work ROM for the CPU 39, which is an 8-bit microprocessor (for example
MB6809E). Now, the control code C ₀ in the received signal B in Fig. 5,
To explain C ₁ to _{C 7} , C ₀ and C ₁ are "1",
It is a clock run signal CR that repeats “0”,
_C2 is a framing code signal of "11100101". _C3 consists of 4 bits of information, 3 bits of humming check code, and 1 bit of parity. _C4
The data after this also has the same structure for each byte. The contents of the information section of C ₃ and C ₄ are summarized in Table 1. Here, only three types necessary for explanation are described. In reality, several types or more are possible. Similarly, Table 2 shows the contents of the 4-bit information section of _C5 .

【table】

Claims (1)

[Claims] 1. A first storage circuit that receives and stores at regular time intervals the viewing time of a television program included in a one-way television signal and billing information A in the form of a digital signal corresponding to the content of the program. a circuit that is provided in a pay television receiving terminal electrically coupled to the television receiver and that determines the billing amount based on the billing information A in the first storage circuit; a second storage circuit composed of a non-volatile memory that stores the charged amount, and a third storage circuit that stores a key signal for decoding the encrypted video signal and audio signal, and a third storage circuit that will become effective in the future. a fourth memory circuit that stores key signals; a write circuit that writes key signals successively sent from the sending side into the fourth storage circuit only once; A circuit that rewrites the amount in the second storage circuit based on the paid viewing fee information B for each terminal, the date of rewriting by this rewriting circuit, and the type of the paid viewing fee information B at that time. Transferring the key signal in the fourth storage circuit to the third storage circuit using a fifth storage circuit configured with a non-volatile memory that stores the flag and a key signal switching signal sent from the sending side. A pay television terminal device provided with a sixth memory circuit for storing information about what has been done.