JPS60171885A - Charging method - Google Patents

Abstract

PURPOSE:To prevent interception by receiving charging information in response to a time viewing a television program and the content of program at each prescribed time and writing a charge data in a nonvolatile memory and displaying it. CONSTITUTION:When a receiver 16 receives a satellite broadcast, an IDU19 amplifies and detects the broadcast and outputs a signal of the base band. A data processing circuit 20 extracts a digital signal in the output, processes it and supplies the result to a descrambler 21. The descrambler 21 switches inversion or non-inversion of the image, rearranges each bit of the digital sound signal and restores it into the normal image and sound. Moreover, a charge is indicated by a control signal superimposed on the video signal of the program in the data processing circuit 20 and stored in a memory. The memory is divided into three parts, a charge proportional to the viewing time at each program is stored in the 1st memory, the content of the 1st memory is added to the 2nd memory at each channel switching or power interruption and the content of the 2nd memory is transferred to the 3rd memory at the reception of charge display command code. When the paid charge data is received, the result is compared with those memories.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention 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 paid programs on ATV (IsATV), it is necessary to pay for the viewing fee 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 unable to receive reception.

These are implemented in pay television in interactive CATV systems.

However, in the case of the 0ATV system, the system requires the sending side to apply for viewing of pay TV via uplink or telephone, so this cannot be used in 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 was exceeded and the processing capacity of the receiving side of the sending side was exceeded.

An example of such a conventional configuration 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, and the creation of control codes. The control code is added to the video signal and transmitted. 3A is its head end, which sends out a plurality of video signals from the CATV center 2 in line with, for example, a VHF midband. 3B is a buffer circuit that receives upstream signals from each terminal, and is connected to the three headends and the terminal side Chu1--/Converter 4 of the 0ATV by a cable of the buffer circuit 3BIiJ1itM- or another cable. Also, a telephone port ak may be used instead of the cable from the tuner/converter 4 to the 271 circuit 3B.

4 converts the mid-band signal to Vl (1 channel of F (
It is a terminal-side tuner or converter that converts one channel of Mitsutono Kundo to one channel '1iVHF01 in channel i according to a command from Kinokudo 6. In addition, 0
If the ATV signal is scrambled, it may be converted to a base note signal, descrambled, and then converted to an RF flaw signal again and output as a VHF one-channel signal.

6 is a television receiver that receives normal VHF band reception.

The viewer applies for the desired program (1)' to the center computer 1 by operating the keypad 6 or via the telephone T. At center 1, charges are set for each terminal, and if scrambled, the key code for decoding is sent in the order of 7 terminal computers 1 → GJLTV center 2 → head end 3 → terminal/tuner 4. The signal is descrambled using this key code in the /converter 4 to reproduce a normal NTSC video signal, convert it to one channel of vHF, and supply it to the television receiver 6. There are a large number of tuner/controllers 4 to telephones 7, and a telephone office is interposed between the telephones 7 and the telephone interface 8. The telephone interface 8 is
In general, requests from human terminals are listened to and converted into the input form of the center controller 1. This is an example.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a billing method that can implement 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 i
o The television signal receiving device receives billing information corresponding to the time spent watching the television program and the content of the program at regular intervals in the form of digital signals, and the billing amount judgment circuit in the receiving device of the terminal calculates the amount. All judgments are made, charge data proportional to the amount is written in a non-volatile memory, and the charge data in the memory is read out and displayed as necessary.

In that case, the non-volatile order memory is divided into three parts, and the first non-volatile memory stores charge information proportional to the viewing time of each program. The contents of the first memory are added to the contents of the second non-volatile memory each time viewing is completed, and the contents of the second memory are added to the contents of the second non-volatile memory upon receiving the charge display instruction code sent from the sending side at regular intervals. The data is transferred to and stored in the non-volatile memory of No. 3.

When receiving data corresponding to the paid charges that are sent separately to each receiving device from the sending side, this data is compared with the contents of the first or second memory, and whether the two are equal or 2. When the contents of the third memory are smaller than the received data, the contents of the second memory. When the content of the third memory is cleared and the received data is smaller than the content of the second or third memory, the difference is stored in the second and third memories, and the difference is displayed. It is characterized by the following.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 2 shows an embodiment of the present invention. In the figure, 11 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.

14 is a receiving antenna installed on the ground.

15 is a low noise converter, for example, the antenna 14
12GHz band signal 11 received at (converted to lz band,
The information is transmitted to the receiver 16.

19 in the receiver 16 is an intermediate frequency demodulation unit (ID
For example, 1GHz band input is 4oOMH2
is converted to the second LF, amplified, detected, and outputs a baseband signal. 20id is a data processing circuit that extracts the output digital signal, processes it, and supplies it to the descrambler 21.

Now, let us assume that the video signal is scrambled using a synchronous shift and random inversion of the video components, and the audio is scrambled using a method where the digital audio sequence is completely changed randomly. When the output of the IDU 19 is directly displayed on the CRT of the color television receiver 17, the brightness of the screen is inverted and the screen is horizontal.

Since vertical synchronization cannot be achieved, the content flows and the content is unclear. Moreover, when the voice is heard directly from the speaker, it becomes noise. Therefore, the disrambler 21 switches between inverting and non-inverting the video based on the output of the data processing circuit 20, and also rearranges each bit of the audio digital signal to restore normal video and audio. scramble). In the A/V reproducing circuit 22, only the horizontal retrace period during the output of the IDU 19, that is, the part from 1 to L2 in FIG.
The level is completely changed, and the output of the descrambler 21 (Fig. 3C) is synthesized with the parts 2 to t, 11, and the original video signal (Fig. 3) is reproduced. 21
Converts the output digital audio signal to an analog audio signal.

The output of this A/V regeneration circuit 22 is converted to V) by the RF modulator 23.
By converting the signal into a signal of an appropriate channel in the IF band and supplying the output to the antenna input of a normal color television receiver 17, the scrambled video and audio can be viewed in a normal, descrambled state.

If you want to watch such scrambled video and audio back to normal images and sounds, you often have to pay a fee. If there is a charge, the charge is indicated by a control digital signal superimposed on the vertical return period (VBL) IC 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 league to the data processing circuit 20 in Figure 2, insert the purchased card (such as a coupon ticket) into the card, and then calculate the amount paid. Data processing circuit 2 only for the time corresponding to
There is a method of sending a descrambling control signal from 0 to the descrambler 21. Alternatively, please contact the bank 18 in advance.
Pay the fee in advance to DB and save the prepaid fee as data.
A code representing the paid fee is sent from the S center 11 via the geostationary satellite 13 to each terminal (each address is individually attached), the fee code is written in the memory of the terminal, and each time a paid program is viewed on the terminal, Change the price code in memory (
There is also a method in which the amount is increased (decreased), and when it becomes "○", the money is paid to the bank 18 again and the above procedure is repeated.

Now, here, the contents of the data processing circuit 2o in FIG. 2 are configured as shown in 31 to 60 in FIG. 4, and when a pay program is received, charge data is superimposed on the VBL period of the video signal. Write the fee according to the viewing time into non-volatile memory, pay the viewing fee to the bank every month, and send the paid fee to the DBS Center 1 for each terminal (each address).
A system in which the content of the memory 47 is reduced by polling and sending data from 1 to 1, and until the content of the memory 47 becomes "o", you will not be able to watch paid programs from the next month.
1 (d Z D U 19) ffj Binary value for waveform shaping the binary data signal superimposed on the middle VBL period into a pulse waveform as shown in the left end part of FIG. 6B. It is a conversion circuit. Reference numeral 32 denotes a clock detection circuit, which uses a clock run signal OR (clockRun) which is a repetition of the 2-byte "1" and "0" signals at the beginning of FIG. The framing code is detected at the 8th bit of the framing code signal FC in the middle to establish frame synchronization, and the sampling clock generated by the sampling clock generation circuit 33 is synchronized with the received signal B. 33 is a circuit that forms a sampling clock of an appropriate phase controlled in this way, and its output is sent to the main clock generation circuit 34.
The frequency is divided by the work RAM37. Work ROM3s,
Centerbrosé Nguniku) (0, PU) 39
It forms the main clock that drives etc.

FIG. 6B from the output of the sampling clock generation circuit 33
A clock is supplied to the sampling circuit 36 in synchronization with each bit of the received signal B, and all bits of the received signal B are sampled. The pulse width of each bit of the received signal B is 5 fs.
c, it is about 175 ns, and it is difficult to operate the work RAM 37 to CPU 39U in FIG. 4 with this period. Furthermore, when an 8-bit microprocessor is used as the CPU 39, it is more convenient to handle the received data as 8-bit parallel signals. Therefore, as the sampling circuit 36, a serial manual-parallel output type shift register such as 5N74LS164 is suitable.

The output is stored in the filter circuit 36 every 8 bits with the 8th bit of the framing code as a reference, and changes at a cycle of μS. This cycle is suitable for the operation of each circuit. Its output is connected to pass line 40.

3 completed tri CPU 3e work RAM, 38 is C
This is the work ROM for PU39, and cptr3s is an 8-bit microprocessor (for example, MB68091c).
It is.

Now, in Fig. 6, the control codes OO+01 to C in the received signal B
To explain about 7, CO and C1 are "1".

It is a clock run signal OR of repeating “0”, and C2
is a framing code signal of "1110o101". It consists of 4 bits of GsFi information, 3 bits of mink check code, and 1 bit of parity.

The data after C4 also has the same structure for each byte. The contents of the information section of C3 and 04 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 05.

Table 1 Table 2 In the case of satellite broadcasting, the 8 bits of C5 and C4 are “0100”.
0000'' and C5 is rloooJ.

Either "0100" or "1100" is used.

The 28 bytes of data in the received signal as shown in Figure 6A is
The case of program data is shown in FIG. 6G. A number indicating the type of program is represented by a 4-byte, 4-digit BGD code as a tag code. Therefore, 9999 types can be specified.

The next keyword is a key code that changes every month. This is essential for descrambling the received signal on the terminal side, and this key code should not be sent from the 1DBs Center to terminals that do not pay the fee. Prevent reception by doing so. U] For example, assume that the fee payment deadline is the 20th of every month, and the key code is changed from the 1st of every month. Since the receiver 16 in FIG. 2 is always energized, it continues to operate unless the power cord is disconnected.

The next charge code is 4 bytes and contains 4 digits of BCD information. The charge code changes over time, and a charge proportional to the time the program was viewed (the time it was displayed on the CRT) is recorded. This content will be described in more detail later.

The next PN key represents the initial value of the PN code for descrambling all of the scrambled signals in 4 bytes (16 bits as information).

The first security measure is to prevent eavesdropping using the PN key.The next month and day are represented by two digits for the month (5BCD) and two digits for the day (1BcD). 4 bits of information x 4 are used.The time is also expressed in two-digit BGD, and the minute is also expressed in two-digit BGD.

When program data packet 2) (05 is "1"), the contents are as described above.

Next, when C5 is "2" (rooloJ) indicating that scrambled data is being sent, 28 bytes (of which 14 bytes are information data) as shown in C'.
All of the bytes) are data, and 14 bytes of information are written to a predetermined location in the work RAM. This data has different contents for each program. There are various possible contents and uses for the scrambled data, but they are omitted here.

Next, when C5 is r3J (rool 1 J), an address data packet is sent in 28 bytes as shown in C". This address data packet is
As shown in Figure CLJ, one packet contains an address indicating a 21-wire terminal. This a'''6 is shown enlarged in Fig. 6.If the first 14 bytes are enlarged, it becomes as shown in Fig. 6.The information bits in the first 7 bytes of D are 7
It is 28 bits of the byte, which is 2, or about 2.
It is possible to distinguish between 6,800,000,000 and one terminal addresses.

The latter 8 bytes are divided as shown in Figure 6E. E indicates only information bits, that is, 32 bits f out of 8 bytes. The 2 bytes at the front end of E (1 byte if it is only information) contain the total maximum of 2 instructions from the DBS center to each terminal.
It is for sending up to 66 types, for example "1J" as shown in Figure 6.
If specified, it will show the total amount of pay TV that the terminal has watched so far. If the amount is set in 267 nt increments, up to $210 can be specified using the 12 bits (1.6 bytes of information in 3 bytes of data) at the right end of FIG. 6. Therefore, when clearing charges, a code for the amount (up to 1,024 dollars and 75 cents) is sent to each terminal, and on the other hand, the amount paid by the terminal to the bank is sent from DBS 7 to 11 to each terminal, and the amount of money on the terminal is The entire contents of the memory 47 are changed. Assuming that the amount of money for viewing is written in the amount memory 47 in increments of 26 cents, if the amount sent from the DBS center 11 is subtracted from the content and the content of the amount memory 47 becomes zero, then is detected by the CPU 39, and the entire key code shown in FIG. 6 is read in. If the amount in the amount memory 47 does not become zero, that is, if the paid amount is insufficient, the key code will not be imported, so you will not be able to decode and listen to the scrambled information (image and audio) from the next month. will no longer be possible. The amount is written to the memory 47 (i.e., subtracted) once a month, and the DBS
If you send rate data from Center 11 continuously for about one week at the end of each month and beginning of January, even if you accidentally turn off the power to the receiver, you will be able to connect the power to the VC even for one day during those two weeks. In this case, the payment amount is written to the amount memory 47 and its contents become zero, and the key code can be read.

Date (time) of writing to key code and amount memory 47
etc. are written into a non-volatile memory 63 similar to the amount memory 47 in FIG. The memory 63 stores the date and time of data writing to the amount memory 47, so that even if the payment is mistakenly paid in two or more installments, the first, second, and
. . . It is used to manage data so that it is correctly written into the amount memory 47.

Next, let's talk about key codes. The key code is composed of 12 bits and indicates a generating polynomial that constitutes a 2-1 PN sequence. For example, if a key code of "01100001ooO1" is sent, the generator polynomial is x +x+x+x-f'(rl
becomes. It may be a polynomial of 11 bits or less instead of 12 bits. Alternatively, the key code may be set to 16 bits, and the mech number in FIG. 6E may be reduced from 1 byte to 4 bits.

Next, the actual operation will be explained. When the terminal device is purchased, the contents of the Pakfu 1 circuit 46 in FIG. 4 are all zero, so when the terminal (assumed to be X) is supplied with power, it first captures the key code. If all terminals are purchased in the middle of the month, the DBS center 11 does not perform regular polling of all terminals, so polling of the number of terminals (for example, 10,000) installed on or around that day will be performed temporarily. go to As is clear from Figure 6, it is possible to poll two terminals in 1H (horizontal period), so 5Hi during the VBL period
When allocated for polling, 10th floor/field = S
OO/sec = 38,000/min, and polling of all newly joined terminals is completed within one minute. Therefore, a newly installed terminal can import the current month's key code within about one minute. If installed before the end of the month, the next month's key code will be sent regularly to all subscribers, but only half of 1H out of 6H of the VBL period will be used for polling the current month's keycode of new subscribers. , as is clear from the previous explanation (
360oO/10) x 3-10.8oO, which means that about 10,000 new members can be polled in about 3 minutes. Assuming that all the subscribers at this point are '1i, ooo million', it is possible to poll all the subscribers in about 61 minutes.

Now, this terminal X has its unique address given in 28 bits. For example, these 28 bits are scattered in a 266-bit memory to prevent eavesdropping, or
The 28-bit address code is written in part of the work ROM 38 or in an independent chip so that a correct address can be obtained by performing an operation on the 28-bit address code according to the keyword. If the calculation is performed using keywords, there is no need to worry about receiving the packet shown in FIG. 5C.

Considering the data transmission efficiency, 6H is transmitted at a rate of once per second.
Assuming that the same packet is superimposed on all the packets and sent out,
On the receiving side, the key code is received within 1 second and the work RA
Write to M37. This keyword is a 16-bit information [
-Have. The second security (prevention of eavesdropping) is achieved by performing calculations using the keyword on the data after the keyword and other data to decrypt all of the encrypted data.

After receiving the keyword, it receives all the packets in the form of "C" in Figure 6 and searches for the 28-bit address of terminal X.
When 28 bits of address in 38 match, Fig. 6E
8 bytes of are taken into the work RAM 37. Since the contents of the amount memory 47 of terminal X are zero, the MSB of the message shown in FIG. Work R with a program like this
Put it in OM38. The following explanation also assumes that the CPU 39 follows the program in the work ROM 38.

In the middle of the month, the MSB is "1", so the key code is 1 (assuming other bits are ignored code assignments).
2 bits are taken into the work RM M37 and pass line 4
0 to the nonvolatile memory 63, where it is stored. Hereinafter, using this key code, Fig. 6 c, a',
Decipher the data of “c”.

If the received program is a paid program, the charge code indicates the charge per unit time. Ideally, for paid programs, the fee should be charged directly in proportion to the viewing time. As one method, here, it is assumed that a 60-minute program costs $6, and charges are charged at 26 cents for every 2.6 minutes. Therefore, as a charge code, the contents of the code are changed every 2.6 minutes, and each time the code changes, the contents of the charge memory in the work RAM 37 are added by 1 byte (equivalent to 25 cents). Memory 4 in memory 47
The charge information data is supplied from 37 to 1, the data in the charge memory of the work RM M37 is incremented by the number of bits corresponding to the viewing time, and the program end data (such as all charge codes being "1" or backup codes) is incremented by the number of bits corresponding to the viewing time. )
When detected, when the reception channel is changed, or when the power is completely cut off, the battery supports 37 to 47 for a short time, and the output of memory 41 (which indicates a multiple of 26 cents) is added and subtracted to 46. and adds it to the contents of the memory 43 and writes the result back to the memory 43.

Non-volatile memory block of Mori A7 consists of three memory sides of 41, 43 and 44, each having 12 bits. If the output of the flag register 46 is rJ, J, or IJ, which instructs addition, the addition/subtraction register 46 performs the addition. Work RAM 37 with battery support for 37 to 470 times for a short time
The contents of the memory 41 and the contents of the memory 43 are added together, and the result is written to the memory 43.

As another method, the DBS center 11 sends the charge code for the cumulative amount of money up to that point every 2.6 minutes from the start of the program, and terminal There is also a method in which the work ROM 38 and the work ROM M37 calculate the calculation and write it to the memory 41, and when the program is finished watching, the contents of the memory 41 are added to the contents of the entire memory 43 and written to the memory 43. In this case, calculate the unit charge every time the charge code changes and
Calculate the number of times 6 cents and store that number in work RAM 3.
7 is incremented, and the incremented result is written to the memory 41 each time.

In either method, each 26 cents worth of time has 41
The contents of are incremented by 1 bit.

Set the amount memory 47 as shown in Fig. 4 (1 each of 41, +3°44).
2-bit non-volatile 1'41. Configure with RAM and work R
The contents of the charge memory in the AM 37 are written to the memo II 41, and the contents of the memory 41 are stored in the memory when you finish watching one program (i.e., when changing channels, detecting an end code, turning off the power, etc.). Add to the contents of 43 and store memory 4
There is also a method in which the data is stored in the memory 43 and read from the memory 43 at the time of reading.

Next, the PN key will be explained. As mentioned above, receiver 1
6 remembers the 12 bits of the key code. The PN key has 16 bits, and the lowest bit (LSB) indicates the initial value of the 12-bit FiPN sequence.
) (MSB) indicates whether to move the PN sequence by bits from the initial value. By substituting the initial value 12 bits h indicated by this PN key as the initial box of the above-mentioned generator polynomial and by software by the number indicated by the above 4 bits, the obtained 12-bit sequence is used to determine whether the video signal is inverted or non-inverted. switching and arithmetic processing of audio signals (audio is 12
(bit quantization) and descramble processing to restore the video and audio to their original state.

Also, as another method, the 12-bit initial 11fk
It is also possible to change the video and audio decoding methods by 1H by shifting 1 bit for each PN sequence f1H obtained by substitution.

The 1st time of the 1st day of the month, etc. are stored in the work RAM 37 and utilized as appropriate.

Next, the fee addition is to be closed after one month or on the 10th of every month, and the entire contents of the memory 43 mentioned above are transferred to the memory 44. This is configured to be automatically performed when the message of price display shown in FIG. 6E is received. As the address at this time, it is possible to use a common number (special number) for all terminals, or to use a packet with the address 'r-simultaneous j' as a backup (7,) in C5. After the price display message, the key code and price code are ignored.

Upon receiving the price display message, the CPU 39 transfers the contents of the memory 43 of the amount memory 47 to the entire memory 44, and writes the contents to the brightness memory 49 via the buffer 48 and the pass line 40. In this case, the contents of the memory 44 are converted into a numerical pattern by the work ROM 38 and the CPU 39, and the numerical pattern is written into the brightness memory 49.
If the contents are read out in accordance with the electron beam set meal of the fORT 62 and supplied to the CRT 63 via the buffer amplifier 61, the charge will be displayed in numbers on the CRT. What is necessary is to add a function to the background display 61 to superimpose the normal program video and charge information, or a function to switch to display only the charge.

Reference numeral 50 denotes an address circuit that provides addresses for writing to the brightness memory 49 and for outputting the bladder.

For terminals that do not pay the displayed fee to the bank by, for example, the 20th of each month, the amount in the address control data is set to zero after the 21st of each month, and the key code is set to "○" and polling continues. As a result, when the key code is changed to a new key code from the 1st of the following month, the terminal will no longer be able to decode data, and scrambled video and audio will not be decoded and cannot be viewed.

Also, if the fee is insufficient, a key code will be sent, but if the contents of the memory 43 have not become zero due to the operation of the CPU 39 of the receiver 16, the key code will not be imported into the non-volatile memory 63. , scrambled′i
'1. The video and audio will not be decoded. Note that if the paid fee is less than the amount stored in the memory 43, it is preferable to automatically display the difference to be paid.

Next, an example of charge settlement will be described with reference to FIG. 4.

When the data corresponding to the paid fee E is sent from the DBS center 11, this data is transferred to work l (AM3
7 to be memorized. Before that, the contents of the memory 43 are transferred to the memory 44 according to instructions from the CPU 39, but by the time the payment is made, the contents of the memory 43 are as follows:
The charges for paid programs watched before receiving the data from the BS center are added to the contents of the memory 43 (Math II).
is larger than the content (numeric value) of the memory 44.

Therefore, the data indicating the paid fee Ef in the work RAM 37 is compared with the entire contents of the memory 44, and when the two are equal, the flags r aO, 1, a2J are set in the flag register 46, and if the fee is larger, The flags 1°al and 1L2J are set.The contents of the memory 44 and the contents of the charge E are subtracted in the register 46, and the result is fully determined and a flag is set.Next, the contents of the charge E and the contents of the memory 43 are compared in the same way. and fee E
is larger than the contents of memory 43, flag 'l: r
aO+ al +○", and each time you finish watching a pay program, the contents of the memory 41 and the contents of the memory 43 (negative number) f! : When the contents of memory 41 become larger than the contents of memory 43, the flag is set to r? L(3TlL+ + 'J
As a result, it is possible to allocate the overpaid fee to the viewing fee for the next month's pay program.

A list of these flags is shown in Figure 3.

When the contents of the memory 44 become zero, the CPU 39 detects al-1 of the flag register 46 and takes in a new key code. If you create a program that does not import new key codes during al-0, you will not be able to watch the next month's paid programs unless you pay the fee.

As described above, according to this billing method, the amount register 47
Eavesdropping cannot be easily done unless the internal configuration of the computer and the contents of the work ROM 38 are made public. Furthermore, work ROM38
Some or all of the contents of the cptr39 internal ROMK
If replaced, wiretapping will be extremely difficult.

Effects of the Invention As described above, according to the billing method of the present invention, the following effects can be obtained.

(1) A pay television system can also be implemented in a one-way transmission system.

(2) A fee is charged in proportion to the amount of time a pay TV program is actually watched.

13) Eavesdropping is difficult.

(4) By changing the viewing time in the minimum unit without changing the minimum unit of charge, the unit price of one program can be determined in small increments.

(6) Good compatibility with teletext systems, etc.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional pay television system, FIG. 2 is a block diagram of a pay television system in which the charging method of the present invention can be fully implemented, and FIG. 3 is a waveform diagram of a video signal in the same system. FIG. 4 is a block diagram of an example of a receiver used in the system, and FIGS. 6 and 6 are waveform diagrams of signals used in the receiver. 11...I) BS center, 12...
Large parabolic antenna, 13...Geostationary satellite, 1
4... Parabolic antenna, 15... Converter, 16... Receiver (8 aircraft, 17...
...Color television receiver, 18...Bank, 19
...Intermediate frequency demodulation unit (IDU)
, 20... data processing circuit, 21...
Desk lamp detection circuit, 33... Sampling clock generation DO path, 34... Main clock generation circuit, 36... Sampling circuit, 36...
... Latch circuit, 37 ... Work RAM,
38...Work ROM, 39...Center processing unique Bcpu), 40...Pass line, 41.43.44...Non-volatile memory, 46 ...Addition/subtraction register, 46...
・Flag register, 47...Amount memory, 49
...Brightness memory, 60 ... Address circuit, 51 ... Buffer amplifier, 62 ...
・CRT, ss...Non-volatile memory. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3

Claims (3)

[Claims] (1) Billing information corresponding to the time spent watching a television program and the content of the program is received at regular intervals in the form of an all-digital signal using a unidirectional television signal, and the billing amount is determined in the receiving device of the terminal. A circuit determines the amount of money, writes charge data proportional to the amount into a non-volatile memory, reads and displays the charge data in the non-volatile memory as necessary, and divides the non-volatile memory into three parts. Charge information proportional to the viewing time of each program is stored in the first non-volatile memory, and the first non-volatile memory stores charge information proportional to the viewing time of each program.
The content of the non-volatile memory is added to the content of the second non-volatile memory, and the content of the second non-volatile memory is added to the third non-volatile memory when the charge display instruction code sent from the sending side is received at regular intervals. When data corresponding to the paid charges sent separately from the sending side to each receiving terminal device is received, the received data is transferred to the second or third non-volatile memory and stored in the second or third non-volatile memory. When the two are equal or the contents of the second or third non-volatile memory are smaller than the received data, the contents of the second and third non-volatile memories are cleared and the received data is the same as the second or third non-volatile memory. If the content is smaller than the content of the second non-volatile memory. A billing method characterized in that the difference is stored in a third non-volatile memory and the amount of the difference is displayed. (2) The received data corresponding to the paid fee, which is sent separately from the sending side to each receiving terminal device, is sent to the third terminal of that receiving device.
Claim 1, which is characterized in that the receiving terminal device operates so as not to accept new decryption information sent from the sending side when the content is small compared to the content stored in the memory of the receiving terminal device. Billing method described in Section 1. (3) Compare the received data and the contents of the second memory, and when the contents of the former are worse than the contents of the latter, the difference is stored in the second memory, and the difference is stored in the second memory. During the period when the flag is present, when moving the contents of the first memory to the second memory, the contents of the second memory are added as a negative number, and the result is added to the second memory. 3. A billing method according to claim 2, characterized in that the billing method is stored in a memory.