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BACKGROUND OF THE INVENTION
The present invention relates to subscription television and more
particularly to a method and system for obtaining billing information
regarding programs viewed by a subscriber of a subscription television
system.
Since the advent of subscription or pay television, numerous techniques
have been devised to bill the subscribers for the services provided. It
has been suggested that the subscriber pay for subscription television
services on a fixed charge basis, a uniform cost per unit use basis, or on
a per program charge basis. More recent systems have adopted the per
program charge basis for billing.
It will be appreciated that a fixed charge or uniform charge per unit basis
of billing presents the least problems with regard to recording and
calculating billing charges. With a fixed charge system as is used with
most cable television or CATV systems, the station operator merely bills
the subscriber a fixed amount on a monthly basis.
The uniform per unit use billing involves somewhat more complex procedures
since actual viewing time must be recorded and somehow made available to
the operator for billing purposes. Moreover, the viewing time must be
registered in conjunction with the identity of each subscriber so that an
individual subscriber can be billed for his viewing time.
The most complex billing system and yet the most desirable from the
standpoint of the subscriber is billing on the basis of actual programs
viewed with different charges for different programs. In such a system,
the billing entity must know both the identity of the subscriber and the
identity of the programs viewed during a billing period.
Several billing systems have been developed in order to charge subscribers
to a pay television system on the basis of programs actually viewed.
Typical of these types of systems are the coinbox systems that are
exemplified by U.S. Pat. No. 3,021,383. In such a system, the subscriber
must deposit a certain amount of money in a coinbox attached to the
receiver in order to view a particular program. Different programs may be
assigned different charges so that, for example, a particular movie may
cost less to view than a sporting event. With such a system, payment for
the program enables the viewing of a program and payment is thus assured.
However, the billing entity (the system operator) must collect the money
from the coinboxes on a periodic basis, requiring considerable manpower
and also requiring access to the subscriber's home.
Another approach to billing on a per program basis requires the subscriber
to place a telephone call to some central location and request the receipt
of a particular program. The calling subscriber's equipment is then
enabled and charges for the program can be recorded and billed to the
calling subscriber. It will be appreciated that such a system may
encounter difficulites in large service areas with a large number of
subscribers. In addition, the subscribers's telephone must be utilized
frequently for this purpose.
Other approaches to the billing problem in pay TV systems include the one
of cards or paper tapes that are used at the subscriber location to record
viewing information. In a particular system, a card is mailed to the
subscriber and is required for operation of the subscriber's receiver. The
card is punched or otherwise imprinted at the subscriber location to
record program charges and must be mailed or otherwise transmitted to the
system operator so that charges may be assessed. Typical of these types of
systems are those shown in U.S. Pat. Nos. 3,470,309, 3,475,547 and
3,531,583.
Another type of billing system may be characterized as a real time metering
or interrogating system such as that shown in U.S. Pat. Nos. 3,396,232,
3,716,654 and 3,733,430. These systems typically interrogate the receivers
or otherwise monitor the status of the receivers on a program by program
basis (e.g., through the use of special transducers) to determine if the
subscriber is watching a particular program. This information can then be
used for billing purposes as well as audience survey purposes and the
like.
It can be seen that the foregoing systems suffer from numerous deficiencies
including system complexity, enormous time consumption, reliance on
subscriber action to receive billing information, and the like. It is
accordingly an object of the present invention to obviate the foregoing
and other deficiencies of the prior art pay television system billing
procedures through the use of a novel method and system for billing on a
per program basis with a minimum of complex equipment and a minimum of
human intervention.
It is another object of the present invention to provide a novel method and
system for obtaining billing information regarding programs actually
viewed by a subscriber of a pay television system wherein program
identification data is recorded and is accessed on a periodic basis from a
central location, thus, eliminating the need for the gathering of the
information through the intervention of the system subscriber.
It is yet another object of the present invention to provide a novel method
and system for obtaining billing information regarding programs actually
viewed by a pay television system subscriber which utilizes a minimum of
complex equipment and makes use of existing equipment at the subscriber
location including a telephone at the location.
It is a further object of the present invention to provide a novel
subscriber television system and method in which scramble and program
codes are received in the program video signal and are used in conjunction
with a telephone access unit to unscramble the received program signal and
record program viewing under the control of a central station linked to
the access unit over non-dedicated telephone lines.
These and other objects and advantages of the present invention will become
apparent to one skilled in the art to which the invention pertains from
the following detailed description when read in conjunction with the
appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a functional block diagram illustrating a subscription or pay
television system in accordance with the present invention;
FIG. 2 is a signal diagram illustrating an exemplary form of the video
portion of the program signal with scramble and program ID codes as
utilized in the system of FIG. 1;
FIG. 3 is a functional block diagram illustrating the central transmitting
station of FIG. 1 in greater detail; and,
FIG. 4 is a functional block diagram illustrating the subscriber station
equipment of FIG. 1 in greater detail.
DETAILED DESCRIPTION
Referring now to FIG. 1, the system according to the present invention
generally comprises central station equipment 10 which supplies program
signals in a scrambled form to subscriber station equipment 12 at each of
the subscriber stations. As will be described hereinafter in greater
detail, the scrambled program signal includes scrambled audio and video
signals as well as various synchronizing signals and codes. The scrambled
program signal SPROG is supplied to the subscribers either by conventional
broadcast or cable techniques.
The audio and video signals from a conventional source such as television
camera equipment are applied to a program signal scrambler 14 to produce
respective scrambled audio and video signals SAUD and SVID. In addition,
the program signal scrambler 14 provides a transmitted scramble code TSC
for transmission with the scrambled program audio and video signals. The
SAUD, SVID and TSC signals from the scrambler 14 are provided to a
suitable conventional transmitter 16 for production of a scrambled program
signal that includes the code signals and for transmission to subscriber
stations.
A program ID code unit 18 synchronized with the scrambled video signal and
scramble code provides a program code TPC for transmission with the
program signals. This program ID code TPC is combined with the scrambled
program video and the scramble code for transmission to the subscriber as
is described hereinafter in greater detail. In addition, the central
station equipment 10 may include a billing data gathering computer 20. It
should however be understood that the billing data gathering computer 20
may be located at any convenient central location and need not be located
at the transmitting site.
The scrambled program signal SPROG from the central station equipment 10 is
received by a program signal receiver 22 at the subscriber station and the
received signal is supplied both to a program signal unscrambler 24 and to
a control and storage unit 26. The program signal unscrambler 24 operates
in response to control signals from the control and storage unit 26 to
unscramble the incoming program signal and provide unscrambled audio and
video signals UAUD and UVID to a conventional modulator 28. The modulator
28 modulates a carrier signal of an appropriate carrier frequency with the
unscrambled audio and video signals and supplies the unscrambled program
signal in the form of a modulated carrier wave to the television antenna
terminals for use by the subscriber's television set in a conventional
manner.
A subscriber control unit 30 provides subscriber control of program
viewing. The subscriber control unit 30 may, for example, include one or
more subscriber manipulated controls which permit the subscriber to
selectively tune a conventional tuner in the program signal receiver 22 in
order to select a desired program as well as to provide appropriate
signals to the control and storage unit 26 indicating that the subscriber
has selected a program for viewing and has thus assumed the obligation to
pay that program.
The control and storage unit 26 detects code signals in the incoming
scrambled program signal for unscrambling and billing purposes. In this
respect, the transmitted scrambled code TSC is detected by the control and
storage unit 26 and compared to a received scramble code RSC supplied to
the control and storage unit through an access unit 32 and stored in the
control and storage unit. The control and storage unit 26 also detects the
transmitted program code TPC in the incoming program signal and stores the
program code of a particular program being viewed. The stored program code
SPC is then supplied on command to the access unit 32. As illustrated, the
access unit 32 is connected to telephone lines which are in turn
connectable through conventional telephone switching equipment to the
telephone lines leading to the billing data gathering computer 20.
In operation, the audio and video program signals are supplied to the
program signal scrambler 14 and are scrambled in any suitable conventional
manner. For example, these signals may be scrambled in accordance with the
techniques described in U.S. Pat. No. 3,824,332 through selective
inversion of portions of the video signal. The scramble code TSC may be
inserted into the video signal in order to permit unscrambling of the
program signals at the subscriber station as is set forth in U.S. Pat. No.
3,824,332.
In addition, each program that is transmitted in a scrambled form may be
identified by placing a program code TPC in the video signal during the
vertical retrace interval of the signal or at any other convenient
location. In this connection, the program code and scramble code may be
combined with the program video at the appropriate locations by
synchronizing the generation of these codes with the video synchronizing
signals in any known manner such as that shown in the reference U.S. Pat.
No. 3,824,332.
The program signal transmitter 16 combines the video and code signals and
transmits this combined signal together with the audio signal at an
appropriate carrier frequency. The resultant video portion of the program
signal may thus take the form illustrated in FIG. 2. For example, as is
illustrated in FIG. 2, the successive horizontal lines of the video signal
are conventionally separated by horizontal synchronization pulses and each
frame of video signals is separated by a vertical retrace interval or
vertical synchronization signal. During the vertical retrace interval,
various equalizing and synchronization pulses are provided and it is in
this interval that the scramble and program ID codes are preferably
combined with the transmitted program signal. These codes are preferably
encoded in a digital form as illustrated in FIG. 2 although it should be
understood that any well known coding technique such as the tone burst
technique described in U.S. Pat. No. 3,824,332 may be utilized.
With continued reference to FIGS. 1 and 2, the transmitted program video
signal is thus in the form of a scrambled signal (e.g., with selected
frames of video information inverted) with codes inserted at appropriate
locations to identify the program being transmitted and to indicate to the
subscriber equipment the state of the subsequent video signal (i.e.,
inverted or non-inverted). The program signal receiver 22 selects a
particular carrier frequency through the use of a conventional tuner and
demodulates the incoming program signal to recover the audio, video and
code signals.
The recovered scrambled program signal is supplied to the program signal
unscrambler 24 and to the control and storage unit 26 for unscrambling and
detection of the codes contained in the video portion of the program
signal. The scramble codes detected in the program signal are used to
generate the control signals that control the unscrambling of the program
signal by the unscrambler 24. The program code in the incoming video
signal is stored in a storage unit that may be selectively accessed by an
access unit 32. The access unit 32 may be, for example, of the type
disclosed in copending U.S. patent applications Ser. No. 683,161 filed May
4, 1976 and Ser. No. 701,033 filed June 29, 1976, both by Robert S. Block
and John R. Martin.
It will be appreciated that the invention provides a relatively simple
manner of subscriber billing that allows for the identification of
programs actually viewed and the rapid gathering of this information on a
periodic basis long after a program has been viewed. Each subscriber
station is selectively accessed so that program viewing information in
association with subscriber identification information is available at a
central location for billing purposes. Moreover, the billing gathering
computer 20 has complete control over the subscriber station equipment 12
in the sense that it can deny new scramble codes to the subscriber station
equipment on a selective basis if that particular subscriber has not paid
his bill or for other relevant reasons.
To facilitate an understanding of the present invention, the central
station equipment 10 and the subscriber equipment 12 are illustrated in
greater detail in FIGS. 3 and 4, respectively.
Referring to FIG. 3, the central station equipment receives the unscrambled
program signal UPROG including the audio and video portions. The audio
portion is applied to a program audio scrambler 40 and the video portion
is applied to both a program video scrambler 42 and to a video sync
detector 44. The video sync detector 44 detects an appropriate
synchronization pulse in the video signal, e.g., the vertical sync pulses,
and supplies the sync pulse to a scramble code generator 46 and to the
program ID code unit 18. The scramble code generator 46 supplies a video
scramble control signal VCS to the program video scrambler 42 and an audio
scramble control signal ACS to the program audio scrambler 40. The program
signal is thus scrambled to produce a scrambled audio signal SAUD and a
scrambled video signal SVID in a conventional manner. In addition, the
scramble code TSC is generated by the scramble code generator 46 so as to
identify the manner in which the program signal has been scrambled.
As was previously mentioned, the program ID code unit 18 receives the sync
signal from the video sync detector 44 and generates the program code
signal TPC. In this connection, a program ID code selector 48 may be
provided to control the generation of a particular program code by a
program ID code generator 50. Thus, the station operator can select a
particular code for a particular program in this manner.
The scrambled audio and video signals together with the scrambled code and
program code are supplied to the scrambled program signal transmitter 16
comprising a signal combiner 52 and conventional modulators and
transmitters 54. The signal combiner 52 receives the scrambled video,
scramble code and program code signals and combines these signals in a
conventional manner to produce a signal such as that illustrated in FIG.
2. This combined signal is then applied to the modulators and transmitters
54 together with the scrambled audio signal for modulation of these
signals onto a suitable carrier wave for transmission.
It will thus be appreciated from the diagram of FIG. 3 that the video sync
detector 44 detects the appropriate synchronization pulse in the video
signal in order to trigger the scramble code generator 46 and the program
ID code generator 50 at appropriate times. For example, the video sync
detector 44 preferably detects the vertical sync pulse during the vertical
retrace interval of the video signal. This vertical sync pulse triggers
the scramble code generator 46 in order to cause the program video signal
to be inverted or passed uninverted at an appropriate time. In addition,
the detected sync signal triggers the scramble code generator and the
program ID code generator in order to synchronize the generation of the
scramble code and program code signals TSC and TPC with the occurrence of
the vertical retrace interval. The audio scramble control signal ACS
generated by the scramble code generator 46 may be any suitable control
signal and need not be synchronized to the video synchronization pulses.
The signal combiner 52 conventionally combines the video and code signals
and the modulators and transmitters 54 provide appropriate modulated
signals for either broadcast or cable transmission.
Referring now to FIG. 4, the program signal receiver 32 at the subscriber
station may include a conventional tuner 56 and a conventional demodulator
58. The scrambled program signal is supplied to the tuner 56 and to the
demodulator 58 for recovery of the scrambled audio and scrambled video
signals. The scrambled video signal, of course, contains the program and
scramble codes in addition to video information. Control of the tuner 56
and thus selection of a particular carrier frequency may be accomplished
in a conventional manner by a control knob on the subscriber control unit
30. The control unit 30 may therefore be referred to as a program select
and accept control since this control also may provide for the application
of an accept signal ACC to the control and storage unit 26 as an
indication that the subscriber has assumed the obligation to pay for a
particular program to which the equipment is tuned.
The scrambled audio signal is supplied to a program audio unscrambler 60
and the scrambled video signal is supplied both to a program video
unscrambler 62 and to a code detector 64 in the control and storage unit
26. The code detector 64, when enabled by the accept signal ACC, detects
the received scramble code RSC and the received program code in the video
signal. The received scrambled code is supplied to a scramble code
comparator 66 and the received program code is supplied to a conventional
signal storage device 68 for storage and later recall by the access unit
32.
The scramble code comparator 66 receives a stored scramble code signal SSC
from the signal storage device 68 and generates the video and audio
unscramble control signals VCS' and ACS', respectively. These two signals
are supplied to the respective program video unscrambler 62 and the
program audio unscrambler 60 in order to reconstitute the scrambled video
and audio signals to their original form prior to scrambling by the
program signal scrambler 14 at the central station equipment. This
unscrambling process may take the form, for example, of that illustrated
and described in previously referenced U.S. Pat. No. 3,824,332. Thus, for
example, when the received scramble code RSC is compared to the stored
scramble code SSC and is identified as an invert signal, the VCS' signal
causes the program video unscrambler 62 to invert the subsequent frame of
video signals. Similarly, when the received scramble code is compared with
the stored scramble code and is identified as a non-invert signal, the
video signal is passed by the program video unscrambler 62 in an
uninverted form.
The access unit 32 is connected to the telephone lines as was previously
described and provides access between the billing data gathering computer
20 and the signal storage device 68. The subscriber station equipment may
be accessed in any one of the various ways disclosed in the previously
referenced copending patent applications of Block and Martin such as
through the timed placement of a call from the access unit 32 to the
computer 20 (e.g., the placement of a call on a monthly basis). Similarly,
when the signal storage device 68 is full and can store no more program
codes, the access unit 32 may place a call to the data gathering computer
20 to transfer billing information thereto.
In this connection, the computer 20 and access unit 32 may be connected
over the telephone lines through conventional telephone switching
equipment as commanded either from the access unit 32 or from the computer
20. After the connection is effected between the computer 20 and the
access unit 32, various data may be transmitted over the telephone lines.
The computer 20 may, for example, initially command the access unit 32 to
transmit the stored program code signals SPC from the signal storage
device 68 to the computer 20. This may be accomplished in any suitable
manner as, for example, by sending a code to the access unit 32 and
generating an interrogate or read signal INT which causes the signal
storage device 68 to supply the stored program codes SPC to the telephone
lines and therefore to the computer 20. Similarly, the computer 20 may
transmit a code to the access unit 32 commanding it to generate a strobe
or right signal STR in order to transmit new scramble codes RSC through
the access unit to the signal storage device 68. During normal operation,
then, the signal storage device may be supplied with scramble codes for
one month's programs and at the end of that month new scramble codes may
be supplied for the next month's programming. At the same time, the
program codes stored in the signal storage device 68 may be accessed and
transferred to the computer 20 so that the subscriber may be billed for
actual programs viewed during the preceding month at various rates for
various programs.
From the foregoing description, it will be made clear that the present
invention may be embodied in other specific forms without departing from
the spirit or essential characteristics thereof. The presently disclosed
embodiments are therefore to be considered in all respects as illustrative
and not restrictive, the scope of the invention being indicated by the
appended claims rather than the foregoing description, and all changes
which come within the meaning and range of equivalency of the claims are
therefore intended to be embraced therein.
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