United States Patent r191
`Davidov
`
`[I I] Patent Number:
`[45] Date of Patent:
`
`4,688,247
`Aug. 18, 1987
`
`[54] PAY TV SCRAMBLING BY AUDIO
`ENCRYPTION
`Inventor: Mircho A. Davidov, Danville, Calif.
`[75]
`[73] Assignee: Oak Industries Inc., Rancho
`Bernardo, Calif.
`[21] Appl. No.: 870,866
`Jun. 5, 1986
`[22] Filed:
`Int. Cl.4 ............................................. H04N 7/167
`[51]
`[52] U.S. Cl . ......................................... 380/19; 380/20
`[58] Field of Search .................. 358/121, 122; 380/19,
`380/20
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`4,318,125 3/1982 Shutterly ............................. 358/121
`4,410,911 10/1983 Field et al. .......................... 358/121
`4,603,349 7/1986 Robbins ............................... 358/121
`Primary Examiner-Stephen C. Buczinski
`Attorney, Agent, or Firm-Kinzer, Plyer, Dorn &
`McEachran
`ABSTRACT
`[57]
`A subscription television distribution system provides a
`
`plurality of sources of television program channels,
`each of which include a video signal and an encrypted
`audio signal with the encrypted audio signal including
`encrypted control and subscriber address data. There is
`a communication link connecting the plurality of
`sources with at least one receiving site such as a cable
`system head end which has means for receiving the
`plurality of television channels. At the receiving site,
`the encrypted audio signals are separated from the tele(cid:173)
`vision channel and are multiplexed together on an non(cid:173)
`television channel carrier. An identifying tag is added to
`each of the video signals for use in subsequently select(cid:173)
`ing the audio signal correspondling to its associated
`video signal when the encrypted audio signals are de(cid:173)
`multiplexed at subscriber locations. At each subscriber
`there is a TV audio decrypter which selects the tag
`from a video signal and uses that tag to demultiplex a
`particular audio signal. The audlio signal is then de(cid:173)
`crypted and is combined with the video signal to pro(cid:173)
`vide program information for the subscriber.
`
`9 Claims, 2 Drawing Figures
`
`WJ-8
`
`/,'EAIJ-EilP
`INTERF;ICE
`
`/IEAIJ·/:l(IJ
`
`AUSTER tPNTRDL CO.MPIITO/f
`
`/2
`
`APPLE EXHIBIT 1076
`APPLE v. PMC
`IPR2016-01520
`Page 1
`
`

`

`U.S. Patent Aug. 18, 1987
`~ :::::...
`h..
`
`~
`1-....
`
`~ ~~
`t\\ ~ ~
`
`N
`~~
`"'-'\~
`
`~ ~
`~~~
`~ ~~~
`~~~
`~
`
`'
`~
`~
`
`~ ~ ~ ~ ~
`
`......
`
`~
`~
`
`~ ~ ~
`~ ~ ~
`~ ~
`~ ~'
`~
`........
`
`~'N
`~
`"
`
`•
`~
`
`Sheet 1 of2
`
`4,688,247
`
`~
`....._
`
`~ ~~
`~~
`
`~~
`~ I 5::i
`
`"'~
`
`I
`I
`I
`I
`I
`I
`I
`
`-
`
`-
`
`-
`-
`
`~~
`~
`l
`
`~ .....
`~ ~ ~
`~
`~ ~
`}~ ~I
`~~
`\f'\
`
`APPLE EXHIBIT 1076
`APPLE v. PMC
`IPR2016-01520
`Page 2
`
`

`

`U.S. Patent Aug. 18, 1987
`
`Sheet2 of2
`
`4.,688,247
`
`~[>
`44
`46
`
`,-----, 5'4
`/;:
`F!J.TER
`
`VI/JEO
`---------1 PLL
`78
`
`LOOP
`FILTER
`
`VtO
`
`8A5E BANP ~~----...r--;_ _ ___.
`PE5tRAM&Er--r-r-----1~!E._lEi~t_JT
`81
`
`82
`
`. -f I -f· 2.
`
`APPLE EXHIBIT 1076
`APPLE v. PMC
`IPR2016-01520
`Page 3
`
`

`

`1
`
`4,688,247
`
`PAY TV SCRAMBLING BY AUDIO ENCRYPTION
`
`10
`
`2
`address control units 14, each of which are connected to
`audio processors 16 which in turn are connected to the
`television channel sources 10. The data from the master
`control computer 12 is fed to the address control units
`14 and from there to the audio processor where the
`audio signal from the television channels are encrypted,
`for example, in the manner described in one or the other
`of the above patents relating to audio encryption. Not
`only is the audio signal encrypted, but the control data
`and address information is similarly encrypted. The
`data may be in a QPSK format. Each of the television
`sources designated 1 through N are connected to an
`M X N selector 18 as are each of the audio processors
`16. Selector 18 in turn is connected to a plurality of
`transmitters 20 designated 1 through M whereby the
`video signals from the program sources and the accom-
`panying encrypted data, are transmitted by antennae 22
`to a satellite indicated at 24. The satellite provides a
`communication link between the transmitting site and
`one of a plurality of receiving sites, one of which is
`illustrated at the right hand side of FIG. 1.
`At each receiving site, and tine site indicated at the
`right side of FIG. 1, may be a typical cable television
`distribution system; there are a plurality of television
`receive only units indicated at 26 which will receive the
`TV channels from the transmitting site. In each case,
`television receiver 26 will provide an output of a video
`signal and a QPSK encrypted audio signal and these
`30 signals will all be passed to a head end interface 28. At
`the head end interface, each of the video signals will
`have added thereto an identifying tag which may be an
`in channel tag and the video signal and its tag will be
`connected to a modulator 30, there being a modulator
`35 for each of the television channels to be transmitted
`from the head end. The modulator will send out over
`the cable distribution system the video signal at an ap(cid:173)
`propriate RF frequency for the cable system. All of the
`encrypted audio signals will be multiplexed in a multi-
`40 plexer 32 and will be separately transmitted on the cable
`at a non-TV channel carrier frequency, for example, at
`an FM frequency. Thus, the distribution of the program
`information on the cable system will be in the form of
`video signals with an identifying tag at an RF television
`carrier frequency and the combined QPSK encrypted
`audio information and control data on the cable at a
`non-TV channel frequency.
`Each subscriber location will include what is desig(cid:173)
`nated as a subscriber box 34, an audio box 36 and a
`television receiver 38. The video signal will be fed to
`the subscriber box which may be a conventional televi-
`sion converter such as shown in U.S. Pat. No. 3,333,198
`and if the video signal is scrambled, it may or may not
`be descrambled in the subscriber box. The output from
`the subscriber box will be a video signal at RF fre(cid:173)
`quency, typically a locally unused channel, which will
`be connected to the audio box. The audio box, as de(cid:173)
`scribed in connection with FIG. 2, will receive the
`multiplexed audio data and will select an audio signal
`appropriate for the video signal selected by the sub(cid:173)
`scriber box 34 and will combine the selected video and
`audio signals for use by television receiver 38.
`FIG. 2 illustrates one form of audio subscriber con(cid:173)
`trol unit. A digital data receiver 40 receives the incom(cid:173)
`ing multiplexed audio signals and is connected to a
`demultiplexer 42. The input from subscriber box 34 is
`indicated at 44 and is connected to an AGC amplifier
`46. The signal from subscriber box 34 will be both the
`
`SUMMARY OF THE INVENTION
`The present invention relates to a subscription televi- 5
`sion system in which the audio portion of subscription
`programs is separated from the video for transmission to
`subscribers and in which the video signals each carry an
`identifying tag for selecting the appropriate audio from
`a demultiplexer at each subscriber location.
`Another purpose is a subscription television decoder
`which has means for selecting the audio signal corre(cid:173)
`sponding to a received video signal from a group of
`multiplexed audio signals.
`Another purpose is a subscription television system of 15
`the type described in which the video signal may or
`may not be scrambled and in which the audio signal is
`encrypted and in which each video signal carries an
`identifying tag for use in selecting the corresponding
`audio signal.
`Another purpose is a TV subscription decoder which
`includes means for decrypting an audio signal and for
`descrambling a video signal and in which the video
`signal carries an identifying tag for use in selecting the
`appropriate audio signal from a plurality of audio sig- 25
`nals.
`Other purposes will appear in the ensuing specifica(cid:173)
`tion, drawings and claims.
`
`20
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The invention is illustrated diagrammatically in the
`following drawings wherein:
`FIG. 1 is a diagrammatic illustration of a television
`subscription distribution system of the type described,
`and
`· FIG. 2 is a diagram illustrating the audio decoder
`used in the distribution system of FIG. 1.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`The present invention has utility in various types of
`subscription television distribution systems. It may be
`used as a part of a cable system, with or without a satel(cid:173)
`lite distribution system and in various other types of
`subscription television distribution systems in which the 45
`audio and/or video signals are encoded or encrypted so
`as to provide security for the transmitted information.
`Various types of video scrambling and audio encryption
`may be utilized and the invention should not be limited
`to any particular code arrangement. For example U.S. 50
`Pat. Nos. 4,340,906; 4,353,088; 4,336,553; and 4,424,532
`all relate to a type of video scrambling which may find
`use in the present invention. Similarly, U.S. Pat. Nos.
`4,531,021 and 4,531,020 both disclose types of audio
`encryption which may be used with the present inven- 55
`tion.
`In FIG. 1, a plurality of sources of television signals,
`both video and the audio associated therewith, are indi(cid:173)
`cated at 10 with the sources being designated source 1
`through source N. Thus the transmitting site may have 60
`any number of television channels or television pro(cid:173)
`gram sources. A master control computer 12 will pro(cid:173)
`vide control data for the descrambling and/or decrypt(cid:173)
`ing of the video and audio signals respectively, if the
`video is scrambled, and will also provide address infor- 65
`mation which is to be associated with the television
`channels for use in controlling system subscribers. Mas(cid:173)
`ter control computer 12 is connected to a plurality of
`
`APPLE EXHIBIT 1076
`APPLE v. PMC
`IPR2016-01520
`Page 4
`
`

`

`4,688,247
`
`50
`
`3
`video signal described and the associated audio carrier
`signal which may or may not have audio information on
`it. The output from AGC amplifier 46 will be the video
`signal and the audio carrier with or without audio infor(cid:173)
`mation and it will be passed to a SAW filter 48.
`There are two outputs from SAW filter 48. One out(cid:173)
`put, on line 50, includes the video and audio modulated
`RF carriers, each with common mode spurious devia(cid:173)
`tion, which are connected to an intercarrier detector 52.
`Detector 52 multiplies the video and audio RF carriers 10
`with the resultant being an intermediate frequency car(cid:173)
`rier signal modulated by the audio information if such is
`present and without common mode spurious deviation
`which was removed in the intercarrier detector. One
`output from detector 52 is connected to an IF filter 54. 15
`Since the output from the detector will include multipli(cid:173)
`cation products other than the desired IF frequency of
`4.5 mhz, the IF filter is required.
`The other output from detector 52 is connected to a
`tag receiver 56 which will identify the tag associated 20
`with the particular video signal and will provide an
`output of this tag to demultiplexer 42 whereby the en(cid:173)
`crypted audio signal associated with the selected video
`signal will be provided at the output of the demulti(cid:173)
`plexer on line 58 along with the encrypted key for the 25
`audio signal, assuming such key is part of the encrypted
`audio data. The encrypted audio and the key for de(cid:173)
`crypting it are both connected to a digital audio decrypt
`circuit 60 with the output of this circuit being one or
`two channels of audio which in turn are connected to a 30
`selector 62. Selector 62 is connected to a remote volume
`control 64 whereby the audio signal may have the vol(cid:173)
`ume controlled before it is combined with the video
`information.
`Connected to the output of IF filter 54 is a divide 35
`circuit 66 which will divide the 4.5 mhz signal down to
`a suitable reference frequency with the output of the
`divide circuit being connected to a mixer 68. Mixer 68 is
`connected to a filter 70 with the resultant reference
`frequency being connected to a voltage controlled os- 40
`cillator (VCO) 72 which receives as its other input the
`audio signal from remote volume control circuit 64.
`The deviation control for VCO 72 is provided by vol(cid:173)
`ume control 64 which is the audio signal at base band
`frequency. In order to maintain the nominal frequency 45
`of VCO 72 at the proper IF level, the output from the
`VCO is connected to a second divide circuit 74 which
`provides the other input for mixer 68. Thus, the combi(cid:173)
`nation of the two divide circuits, mixer 68 and filter 70
`are effective to lock VCO 72 at a 4.5 mhz IF signal.
`The output from VCO 72 is a 4.5 mhz IF signal, audio
`modulated and without common mode spurious devia(cid:173)
`tion which is connected to a mixer 76.
`A second output from SAW filter 48 is the video
`modulated RF carrier, with or without scrambling, but 55
`with the audio carrier suppressed by 45-60 db. This
`signal is connected to a video phase lock loop 78, one
`output of which is connected to AGC amplifier 46 with
`another output providing an AFC control signal for
`subscriber converter 34. A third output from phase lock 60
`loop 78 is the video carrier with common mode spuri(cid:173)
`ous deviation, but without the video modulation. This
`signal is connected to mixer 76. The output from mixer
`76 will be an audio modulated carrier signal, at the
`appropriate RF frequency and with common mode 65
`spurious deviation which has not been affected by the
`volume control applied to the audio signal. The output
`from mixer 76 is connected to a combining circuit 80.
`
`4
`An additional output from phase lock loop circuit 78
`is the video signal, and in this instance with video
`scrambling by way of example, and this is connected to
`a base band descrambler 82. The descrambler is con-
`5 nected to a mixer 84 which combines the unscrambled
`base band video signal with the video RF frequency
`from phase lock loop 78 to provide an unscrambled
`video signal at RF frequency to combining circuit 80.
`The output of the combining circuit is a decrypted
`audio signal at RF frequency and a descrambled video
`signal at RF frequency, both of which can be used in
`television set 78.
`If the video signal and the audio signal provided at
`the output of subscriber box 34 also includes audio in(cid:173)
`formation such as described in U.S. Pat. Nos. 4,340,906;
`4,353,088; 4,336,553; and 4,424,532, the base band de-
`scrambler will provide outputs of the audio information
`at audio base band frequency and these audio signals
`will be connected to a selector circuit 86 which in turn
`is connected to a remote volume control circuit 88 with
`the output from volume control 88 being an alternative
`to the output from volume control circuit 64. Thus the
`encrypted audio and audio channels associated with the
`scrambled video may be alternative audio information
`for the subscriber.
`Whereas the preferred form of the invention has been
`shown and described herein, it should be realized that
`there may be many modifications, substitutions and
`alterations thereto.
`The embodiments of the invention in which an exclu(cid:173)
`sive property or privilege is claimed are defined as
`follows:
`1. In a subscription TV distribution system, a plural(cid:173)
`ity of sources of TV program channels, each including
`a video signal and an encrypted audio signal, with the
`encrypted audio signal including encrypted control and
`subscriber address data,
`a communications link connecting said plurality of
`sources with at least one receiving site having
`means for receiving said plurality of TV channels,
`means at a receiving site for separating the en-
`crypted audio signal in each channel from the
`video signal, means at each receiving site for multi(cid:173)
`plexing the separated encrypted audio signals on a
`single non-TV channel carrier, means at each re(cid:173)
`ceiving site for including an identity tag on each
`video signal for use in selecting the corresponding
`audio signal from said plurality of multiplexed
`audio signals,
`and a plurality of subscribers in communication with
`said receiving site for receiving one or more of said
`video signals and said multiplexed audio signals,
`each subscriber having means for separating the tag
`from its associated video signal and using the sepa(cid:173)
`rated tag to select the encrypted audio signal from
`the multiplexed audio signals which corresponds to
`the tag and its associated video signal, and means at
`each subscriber for decrypting the audio signal and
`its included control and address data.
`2. The subscription TV distribution system of claim 1
`further characterized in that at least one of said video
`signals is scrambled at the source, with each subscriber
`having means for descrambling the video signal.
`3. The subscription TV distribution system of claim 2
`further characterized in that the means for descram(cid:173)
`bling the video signal at each subscriber location is
`separate from and unrelated to the means for decrypting
`the audio signal.
`
`APPLE EXHIBIT 1076
`APPLE v. PMC
`IPR2016-01520
`Page 5
`
`

`

`5
`4. The subscription TV distribution system of claim 2
`further characterized in that the means at each sub(cid:173)
`scriber for using the separated tag to select an audio
`signal and the means for decrypting the audio signal is
`associated with the means for descrambling said video 5
`'Signal.
`5. A TV audio decrypter for use with a TV subscrip(cid:173)
`tion distribution system in which a plurality of en(cid:173)
`crypted audio signals are multiplexed together on a 10
`non-TV channel carrier and in which the correspond(cid:173)
`ing plurality of video signals are transmitted separately,
`each with an identifying tag for its associated audio,
`including
`means for separating the tag from a video signal,
`means for using the separated tag to select the en(cid:173)
`crypted audio corresponding to the video signal
`tag,
`means for decrypting the separated audio, and
`means for combining the decrypted audio signal with 20
`the video signal.
`6. The decrypter of claim 5 further characterized in
`that at least one of the video signals is scrambled, with
`said decrypter further including means for descram- 25
`bling the video signal connected to the means for com(cid:173)
`bining the decrypted audio and the video signal.
`7. A TV audio decrypter for use with a TV subscrip(cid:173)
`tion distribution system in which a plurality of en(cid:173)
`crypted audio signals are multiplexed together on a 30
`non-TV channel carrier and in which the correspond(cid:173)
`ing plurality of video signals are transmitted separately,
`
`15
`
`4,688,247
`
`6
`each with an identifying tag for its associated encrypted
`audio, including:
`a digital data receiver for receiving said multiplexed
`encrypted audio signals, a demultiplexer connected
`thereto,
`video signal receiving means, a tag receiver con(cid:173)
`nected thereto for separating the video signal iden(cid:173)
`tifying tag, said tag receiver being connected to
`said demultiplexer for providing the audio select(cid:173)
`ing signal therefor,
`decrypting means connected to said demultiplexer for
`decrypting the selected audio signal, and
`means for combining the decrypted audio signal and
`the video signal from said video signal receiving
`means.
`8. The decrypter of claim 7 further characterized in
`that at least one of said video signals is scrambled, and
`a video signal descrambler connected to said video
`signal receiving means and to said combining means
`whereby the scrambled video signal is descrambled
`prior to being combined with the decrypted audio sig(cid:173)
`nal.
`9. The TV audio decrypter of claim 8 further charac(cid:173)
`terized in that the video signals transmitted separately
`over the subscription television distribution system in(cid:173)
`clude audio signals, with said video descrambling means
`providing an output of both the descrambled· video and
`the audio signals which accompany it, and means for
`selecting either the decrypted audio signal or the audio
`signal which accompanied the scrambled video for
`combining with the descrambled video.
`* * * * *
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`APPLE EXHIBIT 1076
`APPLE v. PMC
`IPR2016-01520
`Page 6
`
`