United States Patent
`
`[191
`
`[11] Patent Number:
`
`4,759,060
`
`Jul. 19, 1988
`[45] Date of Patent:
`Hayashi et a1.
`
`[54] DECODER FOR A PAY TELEVISION
`SYSTEM
`
`[75]
`
`Inventors: Toshihide Hayashi; Masayoshi
`Kanno, both of Tokyo, Japan
`
`[73] Assignee:
`
`Sony Corporation, Tokyo, Japan
`
`[21] Appl. No.2 793,554
`
`[22] Filed:
`
`Oct. 31, 1985
`
`Foreign Application Priority Data
`[30]
`Oct. 31, 1934 [JP]
`Japan ................................ 59-229348
`May 21, 1985 [JP]
`Japan ................................ 60-110001
`
`Int. c1.4 ........................ H04N 7/167; H04N 7/00
`[51]
`[52] us. c1. ...................................... 380/10; 235/378;
`358/84; 379/131; 455/2
`[58] Field of Search ............... 358/114, 115, 117, 122,
`353/123, 84; 455/2; 380/16, 10; 235/373;
`379/131
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,417,101 11/1983 Serres et a1.
`4,484,217 11/1984 Block et a1.
`
`........................ 379/131
`......................... 358/122
`
`Primary Examiner—Stephen C. Buczinski
`Attorney, Agent, or Firm-”Hill, Van Santen, Steadman &
`Simpson
`
`ABSTRACT
`[57]
`A decoder for a pay television system incorporates a
`receiver for receiving scrambled programming and
`control data transmitted from a remote location, with
`the control data including data corresponding to the
`program fee and the program status, and a manual
`switch for selectively descrambling the program data
`when the program status is a pay-per-yiew program.
`The decoder has a storage unit for storing a credit
`value, transmitted from the remote location, and the
`decoder has timer apparatus for measuring the time
`during which a pay-per-view program is being received
`and for subtracting a program fee periodically from the
`value stored in the storage unit, during the time of re-
`ception of the selected program, provided the switch is
`operated to descramble the program.
`
`3,508,005 4/1970 Hamburger ........................... 358/84
`3,760,160 9/1973 Gieringer et al.
`.................. 235/378
`
`2 Claims, 6 Drawing Sheets
`
`SP 3
`PROCESSING STEP
`
`
`SPII
`
`PAY PER
`
`0
`
`
`VIEW sw 4
`ON 1?
`
`YES
`
`SP'2
`NOT
`DESCRAMBLE
`
`DESCRAMBLE
`
`SP I3
`
`SP I4
`
`SP2!
`
`TIME PAY PER VIEW
`
`PRGM PAY PER VIEW
`
`SP l5
`
`
`NO
`
`UNIT TIME
`
`
`
`ELAPSED?
`
`
`YES
`
`SP 16
`
`SP 22
`
`PRGM
`UPDATED ?
`
`N0
`
`SP 23
`
`as
`
`CHARGE
`
`CHARGE
`
`
`
`Apple Exhibit 4394
`
`v Apple V. SightSound Technologies
`CBM2013-00023
`
`Page 00001
`
`Apple Exhibit 4394
`Apple v. SightSound Technologies
`CBM2013-00023
`Page 00001
`
`

`

`
`L____.________J
` DEPOSIT
`
`OF USER
`
`\
`
`\\
`,__..___L.._____.
`BROADCAST
`CENTER
`
`mama'S‘n
`
`
`8861‘61mt
`
`910I139IIS
`
`090‘6SL‘I7
`
`Page 00002
`
`

`

`DDCD
`
`2B.F
`
`w/
`
`
`
`mm
`
`DBCH
`
`REG 1
`
`FSYN
`
`
`
`
`
`
`
`AUDIO
`DATA
`
`AUD I 0
`DATA
`
`DEPOSIT
`M ONEY
`DATA
`
`ADD '
`RESS
`DATA
`
`U>fim000mCmmmmid
`
`wom>Zwrm920
`
`Samnx>momooom
`
`m>Zomw:.m2Vm>zomwzwANV
`
`
`
`
`
`mmmomnommmojoz000m
`
`
`
`Cm.Humans»
`
`HE.HP5mmmrmmnM0mm
`
`“£ng
`
`33%m<2nooomZoomEm:IZmr
`
`MODE I
`PROM I
`mdficm9:2
`
`USBT
`REG 2
`CHAG
`
`CHCD
`
`DAD 1
`
`DAD 2
`
`DCIN
`
`DADD
`
`Page 00003
`
`
`

`

`
`
`mama'S'n
`
`a :
`
`5
`
`H 3
`
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`00
`co
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`v g
`g.
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`9.,
`&
`
`“4k
`\1
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`
`PCMAD
`
`PC M
`DECODER
`
`21
`
`DAD 1, DAD 2
`
`
`
`
`f4
`
`DES
`
`
`
`
`ADVANCE
`MONEY
`MEMORY
`
`AUDIO
`
`VIDEO
`
`26
`
`27
`
`Page 00004
`
`

`

`FIG 4
`
`SP2
`
`SP4
`
`.
`
`SP5
`
`PAY PER VIEW PRGM
`
`FREE PRGM
`
`PAY PRGM
`
`,
`
`SP6
`
`PROCESQNG STEP
`
`SP3
`
`NOS
`
`SP8
`
`YES
`
`NOT DESCRAMBLE
`
`SP7
`
`DESCRAMBLE
`
`mama‘S'fl
`
`886t‘61'1nr.
`
`9JOi7was
`
`090‘6SL‘I7
`
`Page 00005
`
`

`

`US. Patent
`
`Jul. 19,1988
`
`Sheet 5 of6
`
`'
`
`4,759,060
`
`FIG. 5
`
`sp 3
`PROCESSING STEP
`
`
`SPII
`
`PAY PER
`
`VIEW SW 4
`ON ?
`
`YES
`
`0
`
`SPI2
`
`NOT
`DESCRAMBLE
`
`DESCRAMBLE
`
`SPI3
`
`SP|4
`
`SP2!
`
`TIME PAY PER VIEW
`
`PRGM PAY PER VIEW
`
`SP '5
`
`
`NO
`
`
`UNIT TIME
`ELAPSED?
`
`
`
`
`YES
`
`SP'B
`
`SP 22
`
`PRGM
`UPDATED?
`
`N0
`
`SP23
`
`CHARGE
`
`CHARGE
`
`
`
`Page 00006
`
`Page 00006
`
`

`

`U.S._ Patent
`
`Jul. 19, 1988
`
`Sheet 6 of 6
`
`4,759,060
`
`FIG. 6
`
`CHECK ROUTINE
`
`DEPOSIT
`
`
`FETCH
`CHARGE
`CODE
`
`
`
`
`
` MESSAGE
`OF REQUEST
`FOR DEPOSIT
`
`RETURN
`
`SP 38
`
`Page 00007
`
`Page 00007
`
`

`

`1
`
`4,759,060
`
`2
`
`DECODER FOR A PAY TELEVISION SYSTEM
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention relates to a decoder for a pay
`television system and, more particularly, to a decoder
`suitable for a pay television system using CATV broad-
`casting or DBS broadcasting.
`2. Description of the Prior Art
`Broadcasting systems include CATV (cable televi-
`sion) systems and DBS (direct-broadcasting satellite)
`systems. These systems frequently are used for pay
`television systems using an appropriate converter.
`In a pay television system of this type, a conventional
`decoder for decoding a program of a desired channel
`has mainly two status modes: a free mode and a pay
`mode. The free mode allows free reception of a TV
`program, and the pay mode represents a status mode in
`which a subscriber is charged for reception of a TV
`program.
`More particularly, the pay mode is further classified
`into a flat fee mode, a tier level pay mode and a pay-per-
`view mode. In the tier level pay mode, 3 tier level repre-
`senting the rank of programs to be received by the
`decoder is predetermined. A user subscribes to a desired
`tier level and pays fees to a broadcast station corre-
`sponding to the subscribed tier level. In the pay-per-
`view mode, the user reserves desired programs and pays
`the program fee only for the reserved programs to a
`broadcast station.
`In the conventional pay-per-view mode, user proce-
`dures are cumbersome. When the user wishes to watch
`a pay program in the pay-per-view mode according to a
`first conventional procedure, the broadcast station mails
`a program schedule to each user. The user telephones
`the center by a predetermined date before a desired
`program is to be broadcast (i.e., a week or a day before-
`hand) so as to reserve the desired program. At this time,
`the user pays the fee for the program. When the desired
`program is on the air, the center sends a reservation
`confirmation signal (hereinafter referred to as 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, so that the user
`can watch the desired program.
`In the pay-per-view system described above,
`(A) the user must telephone the center to reserve the
`desired program, which is cumbersome and may be
`inconvenient,
`(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 not
`watch the reserved program, and
`(D) an idle time is required to send the ID signal to all
`reserved users at the beginning of every reserved pro-
`gram.
`According to a second conventional technique which
`represents an improvement on the first conventional
`techique, a pay-per-view status signal is sent from the
`center to each user. When the user wishes to watch a
`
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`program represented by the pay-per-view station signal,
`he depresses a pay-per-view switch located on his tuner.
`The scrambled program is then descrambled, and the
`user can watch the program. When the user actually
`watches the program, charge data transmitted with the
`
`65
`
`subscribed program is stored in an account memory of
`the decoder. The center periodically checks the con-
`tents of the account memory of each decoder, using a
`telephone line, and collects fees or bills the applicable
`charge.
`The second conventional technique effectively solves
`the drawbacks of the first conventional
`technique.
`However, since the center must periodically check the
`account memories of all users, the check system is com-
`plicated. Furthermore, since fee collection is performed
`by use of a telephone line, an auto-dial unit and a
`modem (modulator/demodulator) are required, so that
`the required user unit and center unit are complex and
`expensive.
`
`SUMMARY OF THE INVENTION
`
`It is an object of the present invention to provide a
`decoder for a pay television system wherein a user can
`conveniently use the pay television system with a sim-
`plified payment system.
`In order to achieve the above object of the present
`invention, there is provided a decoder for a pay televi-
`sion system, comprising: an advance account memory
`for storing deposit data sent from a broadcast center;
`means for subtracting program fees from contents of the
`advance account memory for every reception of a pay
`program; and means for manifesting a warning display
`when the contents of the advance account memory
`
`equals less than a predetermined value.
`Furthermore, according to the present invention, the
`pay-per-view mode is classified into two sub-modes to
`prevent unreasonable payment. A first sub-mode consti-
`tutes a time pay-per-view mode for determining the
`charge per unit of time and the second sub-mode consti-
`tutes a program pay-per-view mode for determining a
`charge per program. The tuner decodes a program
`status code signal sent from the broadcast center and
`selects either the time pay-per-view sub-mode or the
`program pay-per-view sub-mode.
`The broadcast center can determine which sub-mode
`applies to programs of different sorts, without interfer-
`ing with the user’s ability to view programs. For in-
`stance, the program pay-per-view mode may be em-
`ployed for a special sports program such as a boxing
`match program while other programming employs the
`other sub-mode. In this way a reasonable charge for any
`program can be made.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Reference will now be made to the accompanying
`drawings in which:
`FIG. 1 is a schematic diagram of a pay-per-view
`system applied to a direct broadcast system utilizing a
`broadcast satellite;
`FIG. 2 is an illustration of a data format of a PCM
`data signal used in the direct broadcast system;
`FIG. 3 is a block diagram of the tuner unit shown in
`FIG. 1;
`FIG. 4 is a flow chart illustrating the operation mode
`of the tuner shown in FIG. 1;
`FIG. 5 is a flow chart illustrating the pay-per-view
`mode of the tuner; and
`FIG. 6 is a flow chart illustrating a control program
`continuously executed by the CPU of the tuner.
`
`Page 00008
`
`Page 00008
`
`

`

`3
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`4,759,060
`
`FIG. 1 is a schematic diagram of a pay-per-view
`system applied to a direct broadcast system utilizing a
`broadcast satellite. A broadcast wave from a broadcast
`satellite 13 is directly received by a receiving parabolic
`antenna 2 and supplied to a DBS (Direct Broadcast
`System) tuner unit 1. Audio and video signals repro-
`duced by the DBS tuner I are supplied to a monitor 14.
`An unscrambled broadcast signal is reproduced by a
`decoder in the tuner I in the free mode. However, in the
`pay mode or the pay-per-view mode, a scrambled
`broadcast signal is descrambled and reproduced on the
`TV screen.
`
`When the pay-per-view mode is utilized by the user,
`the user deposits funds using a cash card 8 or the like,
`advance money from an account within a bank 6 to a
`broadcast center 9. The cash card 8 is conveniently used
`with an automatic teller machine or ATM (not shown).
`The deposit data is transmitted from a computer system
`7 of the bank 6 to a computer system 10 of the broadcast
`center 9. The desired program is transmitted from the
`center 9 to the user through a satellite broadcast link.
`The deposit data is inserted in the data coded in a PCM
`data signal transmitted during a vertical blanking period
`of the video signal. The deposit data is transmitted from
`a transmitter 11 to the parabolic antenna 2 of each user
`through a broadcast parabolic antenna 12 by way of the
`broadcast satellite 13.
`The tuner I of each user has an advance money mem-
`ory, and the deposit data is stored therein. The content
`of the storage can be displayed anytime on a display 5.
`The broadcast center 9 transmits a television signal
`having a PCM data signal PCMAD with the format
`shown in FIG. 2 during a vertical blanking period of the
`video signal. The PCM audio signal PCMAD incorpo-
`rates a plurality of data fields for data of different types.
`Two fields correspond to two (alternately used) chan-
`nels of audio data DADl and DAD2. Also included are
`
`a field for the deposit money data DCIN (representing
`the amount of the deposited fees) and a field for address
`data DADD (including the user ID code). A data code
`field DDCD is added to the above data string, and an
`error check code field DBCH is also added to the end of
`the data string.
`The data code field DDCD contains a frame sync
`code FSYN as the initial data thereof. The following
`data consist of the mode data word MODE, a program
`status code word PROM, a channel code CHCD repre-
`senting a broadcast channel number, first and second
`range bits REG] and REG2 used to expand the com-
`pressed audio data, a scramble sync code SCRM used
`for descrambling the signal, a charge code CHAG rep-
`resenting the program fees, a data code DATE, and
`user bits USBT.
`
`THe program status code PROM comprises a 4—bit
`code signal representing the pay mode assigned to the
`current broadcast program. For example, in one em=
`bodiment the program status code PROM is set to be
`“0000” in the free mode and “0001” in the pay mode.
`The pay-per-view mode is further classified into a
`time pay-per-view mode represented by a code “0101”
`and a program pay-per-view mode represented by a
`code “0110”.
`The free and pay mode are, respectively, a mode for
`allowing free reception of programs and a mode for
`subscription programs on a monthly basis in the same
`
`5
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`4
`manner as in the conventional system. The time pay-
`per-view sub-mode is set to charge for the length of
`listening time, and the program pay-per-view sub-mode
`is set to charge predetermined fees for .the program
`regardless of reception time.
`The broadcast center 9 transmits with each program
`the program status code PROM added to the data code
`DDCD. A proper pay mode is predetermined in accor-=
`dance with the contents of the program by the broad-
`cast station, so that the appropriate program status code
`PROM is added to the data code DDCD, and the resul—
`tant broadcast signal is transmitted to the user. Thus,
`fees can be charged in accordance with charging modes
`suitable for the respective programs.
`In the DBS tuner unit 1 which receives the broadcast
`
`signal, the PCM data signal PCMAD is supplied to a
`PCM decoder 21 (FIG. 3), located within the DBS
`tuner unit 1 (FIG. 1). The PCM decoder 21 decodes the
`PCM audio signal PCMAD to extract the first and
`second channel audio data DADl and DAD2 (FIG. 2)
`which are supplied to an audio processor 22. The other
`data DATA are supplied to a central processing unit
`(CPU) 23 which is preferably a microcomputer. A
`video signal VDIN (which may be scrambled) in the
`broadcast signal is supplied to the input of a video pro-
`cessor 24, which is adapted to unscramble the video
`signal if necessary.
`As shown in FIG. 4, the step SP1 inspects the code
`word PROM and controls subsequent operation ac-
`cordingly. When the program status code PROM repre-
`sents the time pay-per-view mode or the program pay-
`per-view mode (step SP1) a pay-per-view program SP2
`runs under the control of the CPU 23 to perform a
`processing step SP3.
`However, when the program status code PROM
`represents the free mode, a free mode program SP4 is
`executed. In this case, the CPU 23 causes the audio
`processor 22 to decode the audio data DADl and
`DAD2 and the video processor 24 to decode the video
`input signal VDIN.
`When the program status code PROM represents the
`pay mode, a pay program SP5 is executed under control
`of the CPU 23. The CPU 23 determines in step SP6
`whether or not the user ID signal included in the data
`DATA is as same as a unique user ID assigned to the
`tuner unit I. If YES in step SP6, the CPU 23 supplies
`the scramble sync code SCRM to the audio and video
`processors 22 and 24 so as to cause them to perform
`descrambling of the audio data DADl and DAD2 in
`step SP7. Therefore, the audio and video signals are
`both reproduced. However, if the result is NO in step
`SP6, the CPU 23 does not supply the scramble sync
`code SCRM to the audio and video processors 22 and
`24 so as not to cause them to perform descrambling of
`the audio and data DADI and DAD2.
`The audio signal reproduced by the audio processor
`22 is supplied to a digital-to-analog D/A converter 25.
`The D/A converter 25 generates an audio output signal
`AUDIO. The video signal reproduced by the video
`processor 24 is supplied to a buffer amplifier 26. A video
`output signal VIDEO is generated as the sum output of
`an adder 27.
`In the pay-per-view mode, the CPU 23 performs the
`processing step SP3, as shown in FIG. 5. When the
`processing step SP3 is started, the CPU 23 checks in
`step SP11 whether or not a pay-per-view switch 4 is
`turned on.
`
`h
`
`Page 00009
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`Page 00009
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`

`

`5
`As shown in FIG. 1, the pay-per-view switch 4 is
`mounted on the operation panel of the tuner unit 1.
`After the user enters a desired channel with a ten-key
`pad 3, he depresses the pay-per-view switch 4 in case
`when the program is a pay-per-vew program, which
`sets the tuner I in the pay-per-view mode. The recep~
`tion channel number is diSplayed on the display 5. The
`above sequential operations are performed under the
`control of the CPU 23.
`If the result of step SP11 is NO (FIG. 5), the CPU 23
`determines that the user has not set the tuner 1 in the
`pay-per-view mode. Control
`then advances to step
`SP12, and no descrambling is performed. Thereafter,
`the flow returns repeatedly to step SP11. The CPU 23
`thus waits until the user turns on the pay-per-view
`switch 4.
`When the pay-per-view switch 4 is turned on by the
`user, the result of the decision step SP11 is YES. The
`CPU 23 then supplies the scramble sync code SCRM to
`the audio and video processors 22 and 24 for descram-
`bling. The CPU 23 thus controls the generation of both
`the audio and video output signals AUDIO and
`VIDEO.
`
`When the content of the program status code PROM
`represents the time pay-per-view mode, the CPU 23
`fetches this data in step SP14, and the flow advances to
`step SP15.
`The CPU 23 checks in step SP15 the length of view-
`ing time in the time pay-per-view mode. More specifi-
`cally, the CPU 23 checks whether or not a unit time has
`been counted by a timer incorporated in the CPU 23. If
`the result is NO in step SP15, the control flow returns to
`step SP11. The CPU 23 waits until counting of the unit
`time by the timer is completed by a loop of the steps
`SP11, SP13, SPl4, SP15 and SP11.
`_
`When the unit time has elapsed, the result of step
`SP15 is YES. The control flow then advances to the
`charge step SP16, in which one unit time fee is sub-
`tracted from the contents of the memory 28 (FIG. 3).
`This may be a fixed quantity, or a quantity designated
`by the CHAG field of the PCM data. The control flow
`returns to step SP11 again to reset the timer. The CPU
`23 waits for the predetermined unit time to elapse by the
`loop of steps SP11, SP13, SP14, SP15 and SP11.
`In the same manner as described above, the CPU 23
`sends out the audio and video output signals AUDIO
`and VIDEO which are descrambled and reproduced by
`the audio and video processors 22 and 24 while the time
`pay-per-view mode program is being received by the
`user. A fee corresponding to the viewing time of the
`program is subtracted from the contents of the advance
`money memory 28 in the step SP16.
`When the user wishes to stop receiving the program
`in the time pay-per-view mode, he merely turns off the
`pay-per-view switch 4. In this case, the decision step
`SP11 is determined by the CPU 23 to be NO, and the
`CPU 23 then causes the audio and video processors 22
`and 24 to disable descrambling by the loops of steps
`SP11-SP12-SP11 .
`.
`.
`, etc.
`When the user wishes to watch programs in the pro-
`gram pay-per-view mode, the user simply turns on the
`time pay-per-view switch 4 of the tuner I in the same
`manner as in the time pay-view mode. In this case, after
`the decision step SP11 is determined by the CPU 23 to
`be YES, the CPU 23 controls the audio and video pro-
`cessors 22 and 24 to perform descrambling in step SP13.
`In this case, the program status code PROM included
`in the data DATA represents the program pay-per-
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`4,759,060
`
`6
`view mode detected by the CPU 23 in step SP2]. The
`control flow advances to the decision step SP22. The
`CPU 23 determines in step SP22 whether the current
`program being received is the same as the program
`being received when the unit SP22 last had control or
`whether the program being received has been changed.
`If the result is NO in step SP22, the CPU 23 determines
`that the same program is being received. Then the con-
`trol flow returns to step SP11. The user can continu-
`ously watch the program in the program pay-per-view
`mode by a 100p of the steps SP11, SP13, SP21, SP22 and
`SP11.
`When the user wishes to change the content of the
`current program being received, the decision step SP22
`is determined by the CPU 23 to be YES. Then a charge
`is subtracted from the contents of the advance money
`memory 28 at the step SP23, and the flow returns to
`step SP11.
`Once the program is changed, the mode is set to
`continue the changed program. The CPU 23 monitors
`this program by the loop of steps SP11, SP13, SP21,
`SP22 and SP11.
`
`Every time one program is completed or finished, the
`CPU 23 performs charge processing, so that the user is
`charged per program, irrespective of the elapsed time.
`When the user operates the pay-per-view switch 4,
`the mode of the tuner 1 is set to be either the time pay-
`per-view mode or the program pay-per-view mode.
`The CPU 23 supplies to an input of the adder 27 (FIG.
`3) a display signal DES representing that the current
`program is set in the time or program pay-per-view
`mode. For example, numerical value “1” representing
`the time pay-per-view mode or numerical value “2”
`representing the program pay-per-view mode is dis-
`played on the screen of the monitor 14. The user can
`easily visually determine the charging mode being used
`for the current program.
`FIG. 6 illustrates a flow chart of operations continu-
`ously checked by the CPU 23. Normally, control stays
`in one of the loops illustrated in FIG. 5. These loops are
`represented in FIG. 6 by the Fetch Charge Code step
`SP31, which passes control through the Return step
`SP38. The Return step SP38 returns control to step
`SP30 which normally passes control
`to the Fetch
`Charge Code step SP31, to define the loop of FIG. 5
`which is active (for the appropriate sub-mode). Periodi-
`cally, the check routine step SP30 sends control to two
`other paths illustrated in FIG. 5. Preferably this is ac-
`complished by a signal from a timer of the CPU 23
`which interrupts the normal control loop, to check the
`balance data maintained in the memory unit 28 at peri-
`odic intervals, or to update the data stored in the mem-
`ory unit 28 in response to detection of data within the
`DCIN field of PCMAD (FIG. 2). In the loops repre-
`sented by the step SP31, the charge code data CHAG
`superposed on the program by PCMAD is detected by
`the CPU 23, and, as previously described, when the
`program or channel is changed, the step SP31 is exe-
`cuted.
`
`The step SP32 receives control periodically by a
`timer interrupt. Alternatively, execution of a charge
`step SP16 or SP23 (FIG. 5) may include the setting of a
`flag which causes the step SP30 to pass control to the
`step SP32. In step SP32, the CPU 23 compares the
`balance of the advance money memory 28 with the
`charge code CHAG fetched by step SP31. When the
`CPU 23 determines that the balance of the advance
`money memory 28 is smaller than the data represented
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`by the charge code CHAG, the CPU 23 causes the
`monitor 14 to display a message representing a request
`for deposit in step SP37. In this case, the DPU inhibits
`the SCRM signal, so that
`the program cannot be
`watched. The deposit data is checked in step SP33. The
`step SP30 passes control to the step SP33 periodically,
`by a timer interrupt, so that the control data PCMAD
`may be checked for deposit information. Alternatively,
`the step SP30 may check each incoming control word
`PCMAD for deposit data and branch to the deposit
`routine SP33 whenever data is detected within the
`DCIN field. When deposit money data DCIN is de-
`tected as present in step SP33 (FIG. 6), the CPU 23
`checks the ID code included in the address data
`DADD. In this case, if the result is YES in step SP34,
`the deposit money data DCIN is added to the content of
`the advance money memory 28 in step 36. When all the
`routines are completed in FIG. 6, the flow returns from
`the step SP38. Preferably, the advance money memory
`38 comprises a nonvolatile memory device such as an
`MNOS semiconductor RAM.
`With the above arrangement, the pay-per-view mode
`for designating a pay program is classified into time and
`program pay-per-view sub-modes. Charging is deter-
`mined in units of time or programs. Therefore, a reason-
`able charging system suitable for the purposes of users
`can be established.
`A desired program need not be reserved by tele-
`phone, and the user can conveniently enjoy the direct
`broadcast satellite system. If the user does not watch a
`reserved program no charge is made. Furthermore,
`when the pay-per-view switch 4 is depressed, the user
`can watch any program at any time, provided the sum
`stored in the memory 28 is enough.
`Since the user is not charged through a telephone line
`(bidirectional communication system), the configura-
`tion of the user’s receiver and the broadcast center
`system can be simplified and made less expensive. The
`user simply receives a message via SP37 representing a
`request for a deposit when the value of the advance
`account memory is less than the predetermined value
`which is needed for viewing a particular program. The
`user pays a fee in accordance with the message, or else
`has it automatically deducted from the memory 28, so
`that a simple efficient system can be provided. In the
`pay-per-view system of this embodiment, the transmis-
`sion line from each user to the center comprises a link
`through a bank or the like. Such a link may be located
`at the user’s home, or a public link may be used such as
`the link of a bank’s automatic teller machine or ATM.
`Program fee data, deposit amount data, and the like are
`sent from the center to the user through a transmission
`line using the regular broadcast channel as shown in
`FIG. 1. Shortage of a deposit amount is automatically
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`displayed by the user’s monitor. Therefore, a conversa-
`tional two-way communication between the user and
`the center is provided, though only a one-way line
`terminating at the user’s home is actually used.
`According to the present invention, the center may,
`but need not, send the ID signal to all users when pay-
`ment data is obtained. Many control words relative to
`payment data can be sent to users within a limited time,
`and additional information such as a text or meSSage can
`be sent, if desired.
`The above embodiment exemplifies a DBS broadcast
`system. However, the present invention can be applied
`to other pay broadcast systems such as a cable television
`(CATV) system. The present invention can also be
`applied to an audio pay broadcast system.
`Alternatively, in the above embodiment, the fee cor-
`responding to the actual viewing time detected by the
`timer incorporated in the CPU 23 can be subtracted
`from the contents of the advance account memory peri-
`odically, by means of a timer interrupt procedure,
`which is enabled during the course of a pay mode.
`According to the present invention, charging is deter-
`mined in units of time and programs, so that a reason-
`able charging system can be established to suit for user’s
`interests.
`What we claim are:
`
`l. A decoder control circuit for a pay television sys-
`tem comprising:
`'
`means for descrambling a selected video program
`transmitted from a center at a remote location;
`means for receiving and decoding control data trans-
`mitted from said center, said control data including
`at least program fee data and program status data;
`advance money memory for storing money data
`transmitted from said center; and
`control means for subtracting a program fee from the
`money data stored in said advance money memory
`upon reception of said selected program;
`said control means including a manual switch for
`selectably allowing descrambling of said program
`when said program is a pay-per-view program, as
`represented by pay-per-view status data in said
`control data; and
`said control means including timer means adapted to
`measure the time during which said program is
`received, and for controlling said subtraction based
`on the measure of reception time.
`2. The decoder control circuit as claimed in claim 1,
`including means for activating said timer means when
`said manual switch is turned on, and for deactivating
`said scrambling when said manual switch is turned off
`during the period of reception of a time pay-per-view
`program.
`*
`*
`*
`*
`It
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