RECEIVER FOR PAY TELEVISION

Abstract: Receiver for pay television. A payment control apparatus for a pay television system comprises means (24) for detecting advance data which corresponds to a deposit of a user and is transmitted from a broadcasting center (6), an advance memory (34) coupled to said detecting means (24) for storing said advance data, an error check controller (31) coupled to the detecting means (24) for detecting errors in the advance data, and display means coupled to the error check controller (31) for display­ ing error conditions in the advance data.

Description: The present invention relates to a receiver for pay television and more particularly to a payment control apparatus for a pay television system. Description of the Prior Art: In a conventional pay per view system for collecting listening fees, a broadcast center (i.e., a broadcast station) mails program schedules to each user in advance. The user calls the center by a predetermined data before a desired program is to be broadcast (e.g., a week or a day beforehand) so as to reserve the desired program, if any. When the desired program is on the air, the center sends an ID signal to a user who has reserved the corresponding program. When a user's receiver or a decoder in the receiver receives the ID signal, a scrambled program signal is descrambled by the decoder. The above described pay per view system has the following disadvantages: (A) the user must call the center to reserve the desired program, (B) each program has a reservation due date, so that the user cannot reserve the desired program when the reservation due date has passed, (C) fees cannot be refunded even if the user does no watch to reserved program, and (D) a spare time is required to send the ID signal to all reserved users at the beginning of every reserved program. In another conventional pay per view system, a pay per view status signal is sent from the center to each user. When the user wishes to watch a program represented by the pay per view status signal, he depresses a pay per view switch arranged in a decoder in a tuner. The scrambled program is then descrambled, and the user can watch the program. When the user actually watches the program, charge data corresponding to the subscribed program is stored in a memory in the decoder. The center periodically checks the contents of the memory of each decoder through a telephone line and collects fees or bills the charge. This conventional pay per view system can solve the drawbacks of the first conventional system. However, since the center must periodically check the memories of all users, the check system is complicated. Furthermore, since fee collection is performed through a telephone line, an audio dial unit and a modem (modulator/demodulator) are required, so that the user terminal and the station apparatus are complex and high-cost. Another pay per view system is proposed. In this system a user deposits an advance money to the broadcast station through a bank or the like, and the broadcast station sends the advance data together with ID (or address) data to the user via a PCM area of a TV broadcast channel. The advance data representing the deposit is stored in the advance memory of the receiver of the user. Every time the user watches a pay program, a program fee is subtracted from the advance data. According to this system, no modem for connecting the receiver to the telephone line is required. In addition, a fee collection system using a telephone line need not be installed in the broadcast center. It simplifies the system configuration. In the latter above described pay per view system, since the TV broadcast channel is used as a charge link, an error may occur in the advance information due to atmospheric or airplane noise. However, since the TV broadcast channel is a one-way transmission line, the sending end (i.e., the broadcast center) cannot detect a transmission error. SUMMARY OF THE INVENTION The present invention solves the conventional drawbacks described above. It is an object of this invention to provide a pay per view system wherein an advance information error can be detected at a receiving end or at a user's terminal, and a feedback path can be substantially formed to acknowledge the error so that the broadcast center corrects the error. In order to achieve the above and other objects of the present invention, there is provided a payment control apparatus for a pay television system in which a subscriber purchases viewing time by advance payment to a broadcast center from which pay television programs are sent and are controllably made accessible to said subscriber as a function of said advance payment, said broadcast center being operatively connected to a bank through which said subscriber effects advance payment and transmitting information relative thereto in the form of advance payment data, said apparatus being at the location of said subscriber and comprising : a detector receiving iterated data sequences addressed thereto from said broadcast center relative to said advance payment; a memory coupled to said detector for storing said data relative to said advance payment; a controller connected to said detector comprising means for checking whether the received iterated data sequence contains an error with respect to said transmitted data sequence, said error being detected when fewer than half of said information iterations received coincide with each other, and display means operatively connected to said controller to signal an error message when incorrectly received data has been fed into said memory, so that said user can inform said broadcast center and ask for said advance payment data to be sent again. Thus, according to the present invention, an advance data transmission error can be acknowledged to the broadcast station. BRIEF DESCRIPTION OF THE DRAWINGS Fig.1 is a block diagram of a pay per view system using a DBS (Direct Broadcast Satellite) channel; Fig.2 is a front view of a front panel on a subscriber's tuner; Figs.3 and 3A are a block diagram showing main part of the tuner; Fig.4 is a format of transmitted data; Figs.5, 6, 7, 9, 10, 12, 13, and 15 are flow charts for explaining the operation of the pay per view system; and Figs.8, 11 and 14 are front views of a television screen which represents an advance balance statement, a balance shortage caution message and a deposit data transmission error message, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will be described with reference to an embodiment which exemplifies an information transmission system utilizing a broadcast satellite channel. The present invention may be applied to a normal TV broadcast system or a CATV (cable television) system. Fig. 1 is a block diagram of a pay per view system utilizing a DBS (Direct Broadcast Satellite) channel. A direct broadcast wave from a broadcast satellite 10 is received by a parabolic antenna 2 and is demodulated by a DBS tuner 1. The broadcast signal subjected to predetermined scrambling and transmitted to a tuner is decoded (descrambled) by a decoder in the tuner. The descrambled program is watched by a user on a television monitor 11. In this pay per view system, each user(i.e., a subscriber) deposits advance money with a cash card 5 or the like from a bank 3 to a broadcast center 6. The advance data is transmitted from a computer 4 of the bank 3 to a computer 7 to of the broadcast center 6. The advance data or deposit data is then transmitted from the center 6 to the user through a broadcast satellite link by utilizing a PCM data area or a vertical blanking period of a TV signal. Each data is assigned with an individual user's ID code, and composite data is transmitted from a transmitter 8 to the broadcast satellite 10 through a transmitting parabolic antenna 9. The data is then sent from the broadcast satellite 10 to the tuner 1 of each user through the receiving parabolic antenna 2. The tuner 1 (decoder) of each user has an advance memory for storing the advance data deposited by the user through the bank. The advance data is displayed on a data display unit 102 in the tuner 1. When a pay program is transmitted to the user, a "pay per view" program status data is supplied from the broadcast center 6 to the user through the broadcast satellite channel upon broadcasting. When the user wishes to watch this pay program, he performs channel selection and a key code input for execution of pay per view with a ten-key pad 101 or the like in the tuner. The decoder de-scrambles the scrambled program to be watched on a television monitor 11. At the same time, data corresponding to the program fee is subtracted from the advance money memory in the decoder. Thus, the pay per view operation is brought to effect. When the advance data in the advance memory is decreased below a predetermined value by several times of subtractions, a message requesting for additional deposit is displayed on the TV screen or the display unit 102. Fig.2 is a front view of an operation panel of the DBS tuner 1 of Fig. 1, and Figs. 3 and 3A is a block diagram of the tuner 1 (indoor unit). When the user depresses a power switch 100 on the operation panel, the tuner 1 is set in the standby state, and a standby LED 102f in the display unit 102 is turned on. Referring to Figs. 3 and 3A, in the standby state, a DBS reception signal is supplied to a tuning circuit 12. The DBS reception signal is tuned and detected by the tuning circuit 12 and is supplied as a video signal, e.g., an NTSC signal to a video processing system. An output from the tuner circuit 12 is also supplied as a detection output to an output terminal T7. Tuning is performed at the ten-key pad 101, and a micro-computer 13 for tuning control supplies a tuning signal to the tuning circuit 12 through a PLL prescaler unit 14 in response to tuning operation data. A channel number is displayed by a channel display LED 102a (Fig.2) in the display unit 102. A polarization discrimination signal from the micro-computer 13 appears as a control output at an output terminal T8 through a polarization control amplfier 21. The control output is supplied to an outdoor unit 5SHF-to-UHF converter) built into the parabolic antenna 2. A high-frequency PCM area component of the video signal as an output from the tuner circuit 12 is eliminated by a low)pass filter (LPF) 15. The scrambled signal is de-scrambled by a de-scrambling circuit 16. The spectrum of a signal transmitted with energy dispersal restores the original spectrum by means of an anti-dispersal circuit 17. An output from the anti-dispersal circuit 17 appears at a video output at an output terminal T3 through a clamper 18. An output at the output terminal T3 is supplied to the television monitor 11. In order to couple a VTR, a video output from the anti-dispersal circuit 17 is modulated by an RF modulator 19 to an RF signal of a proper channel frequency. The RF signal is supplied from an RF output terminal T2 to the VTR through an RF switch 20. An antenna reception signal of a VHF or UHF television broadcast wave is also supplied from an input terminal T1 to the RF switch 20. The VHF or UHF television broadcast signal and the RF output are switched and selectively supplied to the terminal T2. This switching operation is performed by a DBS/TV switching button 103 of Fig.2. When the DBS tuner is selected, a DBS LED 104 is turned on in synchronism with the switching button 103. PCM area data included in the high-frequency component of the output from the tuner circuit 12 is extracted by a band-pass filter (BPF) 22. The extracted 4-phase 5QPSK) modulated data is demodulated by a QPSK decoder 23 and is supplied to a PCM processor 24. Fig.4 is a one-frame format of an output from the decoder 23. A control code such as a stereo/monaural code is sent following a data sync (SYNC). In addition, when a pay program is transmitted, a program code, fee data and scramble status data are sent. Program status data (i.e., free program, pay program by reservation, or pay per view program discrimination status data) follow the scramble status data. Subsequently, four audio data (1) to (4) are transmitted. In the next free area, a specific subscriber message and advance (deposite) data are sent together with a subscriber address (ID data). Within this area, the program schedule is also sent. The last one-frame data comprises an error correction code. The PCM processor 24 de-interleaves the data of Fig. 4 in response to an output from a RAM 25 for storing de-interleaving data and also performs error correction in accordance with/error collection code. When a transmitted program is a pay program, the PCM processor 24 de-scrambles audio data in accordance with the scramble status data. At the same time, the scrambled data is also supplied to the video de-scrambling circuit 16, so that the video signal is de-scrambled. Processed outputs from the PCM processor 24 appears as L-and R-channel audio outputs at output terminals T5 and T6 through a D/A converter 26, a stereo/monaural audio switch 27, low-pass filters 28L and 28R and buffer amplifiers 29L and 29R. Upon operation of an audio selection button 105 in the operation panel of Fig. 2, one of the four audio data (1) to (4) can be selected. A selection number is indicated by ON states of LEDs 102b in the display unit 102. At the same time, the station number of the DBS broadcast and the stereo/monaural mode are indicated by the LEDs 102c. At the time of reception of the pay per view program, "pay per view" program status data is transmitted together with fee data. As shown in a flow chart of Fig. 5, the PCM processor 24 detecting this status data in step 1 causes the pay per view LED 102g to flicker, for acknowledging the subscriber that the current program is a pay per view program. When the subscriber wishes to watch this program, he enters a key code with the ten-key pad 101 of the tuner 1 in step 2. The entered key code is supplied from the micro-computer 13 to a pay per view micro-computer 31. The entered key code is compared for identification with a user-defined code registered in a key code memory 32 in step 3. When a coincidence is detected in step 4, the program fee is subtracted from the advance data in an advance memory 34. Thereafter, predetermined de-scrambling is performed, and the subscriber can watch the desired program (step 5). Thus, only the person who knows the key code can watch the program. Therefore, children cannot watch adult programs, and the subscriber will not be charged due to mischievous tuning operation by children. The fee data transmitted from the broadcast station is stored in a fee memory 33 and is displayed on the TV screen for a short period of time, e.g., three seconds. When the user depresses a fee button 106 in the operation panel of Fig. 2, the program fee can be displayed at any time on the screen during program listening. When reception of pay per view program starts, the program fee is subtracted from the advance data in the advance memory 34. Every time the subscriber deposits (transfers) an advance, the advance data is updated in the advance memory 34. The deposit data is transmitted from the broadcast center together with the subscriber address data by utilizing the free area of the PCM data, as indicated in the data format of Fig. 4. When the deposit data input is detected (step 6), as shown in a flow chart of Fig. 6, the PCM processor 24 compares (identifies) the transmitted address data with the subscriber address data stored in the ROM 35. When a coincidence is detected by the PCM processor 24, the deposit data and the deposition date data are decoded (step 8), and the decoded data are stored in the advance memory 34 (step 9). When a balance button 107 in the operation panel of Fig. 2 is depressed (step 10), a balance sheet of the advance memory 34 can be displayed on the screen any time, as shown by a flow chart of Fig. 7 (steps 11 and 12). As shown in the television screen of Fig. 8, the display contents are the deposit mount, the deposit date and the balance for each channel. The subscriber can deposit an additional advance by checking the balance displayed on the television screen and judges whether or not an additional advance is required. The contents of the advance memory 34 are transferred from the pay per view micro-computer 31 to a message micro-computer 36. An output from the message micro-computer 36 is converted by a character generator 37 to a display signal. The display signal is thus displayed on the television screen. The character generator 37 is operated in response to a sync signal from a sync separator 38. When the balance in the advance memory 34 descreases below a predetermined amount SX (step 13 of Fig.9) as a result of watching pay per view programs a plurality of times, an error display LED 102d in the display unit 102 in the operation panel of Fig. 2 is turned on in step 14 in the flow chart of Fig. 9. A redeposit request (i.e., balance shortage status data) is generated from the pay per view micro-computer 31 and is transferred to the message micro-computer 36 (step 15). The message micro-computer 36 detects the balance shortage status (step 17) and supplies the balance shortage message data to the character generator 37 (step 18) when the balance button 107 is depressed in step 16, as shown in a flow chart of Fig.10. The character generator 37 generates a character display signal corresponding to the message data. The character display signal is superposed on the video signal from the anti-dispersal circuit 17. The superposed signal is displayed as a message on the television screen. When a predetermined period of time, e.g., 10 seconds, has elapsed, the same balance sheet as in Fig. 8 is displayed (step 19). The pay per view micro-computer 31 checks whether or not there is an error in the deposit advance data transmitted from the broadcast center 6. The error check is performed by decision by majority. Identical data is transmitted five consecutive times. When three out of five data coincide with each other, the pay per view micro-computer 31 determines that no transmission error occurs in deposit data. However, when only two data are detected to be coincident with remaining three data being inconsistent, the micro-computer 31 determines that transmission error occurs in deposit data. When the micro-computer 31 determines in step 20 that a data transmission error occurred, as shown in the flow chart of Fig. 12, the operation panel error display LED 102d flickers in step 21 and error status flag data is supplied to the message micro-computer 36 in step 22. When the user notices flickering, he depresses the balance button 107 in step 23. As shown in the flow chart of Fig. 13, the message micro-cpmputer 36 detects the data error status (step 24) and supplies to the character generator 37 a message representing that "error in deposit data!" in step 25. The message shown in Fig. 14 is displayed on the television screen in accordance with the output from the character generator 37. When 10 seconds have elapsed, the balance statement is displayed in step 26 in the same manner as in Fig. 8. The user calls the center after checking the balance statement and asks for the deposit data to be resent. The deposit data is sent again, and the correct deposit data is stored in the advance memory 34. However, the broadcast center 6 cannot catch that a tansmission error actually occurs. Double deposit money entry may be performed due to a false claim for data transmission error. For this reason, the pay per view micro-computer 31 prevents double advance money entry by referring to advance deposit date data transmitted together with the deposit data. In a flow chart of Fig. 15, when an address (ID) assigned to the advance data coincides with the subscriber address in step 27, the deposit data is stored in the advance memory 34. In this case, the new deposit data is written in the memory 34 in step 28, only when the advance (deposit) date data represents a date later than the date in the advance deposit data memory 34. When the date of the deposit data transmitted from the broadcast center coincides with that of the data stored in the memory 34, or is older, new deposit data will not be stored in the advance memory 34. Therefore, double deposit in the memory can be prevented in steps 29 and 30. Alternatively, a deposit serial number data can be transmitted together with the advance data, so that the advance data can be stored in the memory 34 only when the advance serial number data is incremented. When a message (private message) to a specific subscriber is included in the free area of the PCM data of Fig. 4, the subscriber address is compared with a destination address attached to the message data. When a coincidence is detected by the PCM processor 24, the message is stored in a RAM 39 through the message micro-computer 36. Message reception is indicated by the message LED 102e in the display unit 102 of Fig. 2. When the subscriber notices that the LED 102e is turned on, he depresses a message button 108 in the operation panel. The message data is read out from the RAM 39, and the readout data is supplied to the character generator 37 through the message micro-computer 36. The character signal output is displayed as message characters on the display screen. This display can be cancelled upon depression of the message button 108 again. When a clear button 109 in the operation panel is depressed, the message data can be erased from the RAM 39. The messsage RAM 39 has an area for storing the program schedule transmitted by utilizing the free area of the PCM data. When the user wishes to watch the program schedule, he depresses a TV guide button 110 in the operation panel of Fig. 2. The program schedule data is supplied from the PCM processor 24 and is stored in the RAM 39 through the message micro-computer 36. The data read out from the RAM 39 is converted by the character generator 37 to a character signal as a video signal. Thus, the program schedule is displayed on the television screen. As is apparent from the above description, data of the advance money deposited by the user is transmitted from the broadcast station and is stored in the advance memory of the user, and the program fee is subtracted from the advance data stored in the advance memory every time the user watches a pay program. The user can watch desired programs any time without reservations. The broadcast center need not install an expensive fee collection system using, for example, a telephone line, but needs only a simple charge system which transmits deposit data and program fee data to the user through the broadcast channel. Furthermore, data transmission error is detected and displayed on the diplay unit or television screen. Even if the broadcast center cannot detect the transmission error since a one-way broadcast channel is used in the charge system, the user can find the trqnsmission error and call the broadcast center to ask for the error to be corrected. In other words, even if a one-way communication path is used, a substitute for feedback path for transmission error correction can be substantially constituted. It provides a charge system with high reliability.

Claims: A payment control apparatus for a pay television system in which a subscriber purchases viewing time by advance payment to a broadcast center (6) from which pay television programs are sent and are controllably made accessible to said subscriber as a function of said advance payment, said broadcast center (6) being operatively connected to a bank (3) through which said subscriber effects advance payment and transmitting information relative thereto in the form of advance payment data, said apparatus being at the location of said subscriber and comprising : a detector (24) receiving iterated data sequences addressed thereto from said broacast center (6) relative to said advance payment; a memory (34) coupled to said detector (24) for storing said data relative to said advance payment; a controller (31) connected to said detector (24) comprising means for checking whether the received iterated data sequence contains an error with respect to said transmitted data sequence, said error being detected when fewer than half of said information iterations received coincide with each other, and display means (102d) operatively connected to said controller (31) to signal an error message when incorrectly received data has been fed into said memory, so that said user can inform said broadcast center (6) and ask for said advance payment data to be sent again. The payment control apparatus according to claims 1, characterized in that said advance payment data comprises a data sequence wherein information relative to said advance payment is iterated a predetermined number of times, and in that said error checking means comprises a majority decision means which detects said error when fewer than half of said information iterations received coincide with each other. The payment control apparatus according to claim 2, characterized in that said information relative to said advance payment is iterated five times, said error being displayed when fewer than three information iterations received coincide with each other. Payment control apparatus according to claim 1, characterized in that it further includes means (16) for de-scrambling a selected one of television programs transmitted from the center (6), and control means for subtracting a program fee from the advance data stored in said advance memory (34) upon reception of the program. The payment control apparatus according to any one of claims 1 to 3, characterized in that it further comprises means for controlling access into said pay television system by use of a user-definable key code, said means comprising : a key input device (101) whereby a key sequence can be entered by said user; a key-code memory (32) for registering said user-definable key-code; said controller (31) being operatively connected to said key-code memory and said key input device (101) for comparing said registered user-definable key-code with said key sequence entered on said key input device; said controller also being operatively connected to said payment control apparatus for authorizing access to a pay program only upon coincidence of said key sequence and said registered user-definable key-code. The payment control apparatus according to claim 5, characterized in that said means for restricting access controls the operation of de-scrambling means (16) and said fee subtracting means after comparing said user-definable key-code and said data from said key input device (101).

Inventors: HAYASHI, TOSHIHIDE, KANAYAMA, IKUO, KANNO, MASAYOSHI
Applicants: SONY CORPORATION
Application year: 1985
Main classification: H04N7
IPC codes: H04N7, G07F7