119
`United States Patent
`Summersetal.
`
`4,306,250
`(11
`
`[45] Dec, 15, 1981
`
`[54] TELEVISION RECEIVER ARRANGEMENT
`HAVING MEANSFOR THE SELECTIVE USE
`OF SEPARATED OR LOCALLY
`GENERATED SYNCHRONIZING SIGNALS
`
`[75]
`
`Inventors: Christopher P. Summers, London;
`Richard E. F. Bugg, Croydon; John
`R. Kinghorn, Sutton, all of England
`
`(73] Assignee: U.S, Philips Corporation, New York,
`N.Y.
`
`[21] Appl. No.: 179,125
`[22] Filed:
`Aug. 18, 1980
`
`Related U.S. Application Data
`
`{63]
`
`Continuation of Ser. No. 945,064, Sep. 22, 1978, aban-
`doned.
`
`Foreign Application Priority Data
`[30]
`Sep. 26, 1977 [GB] United Kingdom............... 40032/77
`May 30, 1978 [GB] United Kingdom............... 40032/78
`(51) Unt. C13 ose: HOON 5/04; HO4N 7/08
`
`
`[S2). Se ha scpesccessteiusssccsassasivacerecscnses 358/148; 358/147
`[58] Field of Search ................. 358/12, 142, 147, 149;
`340/721, 745, 789, 814
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`vee 358/149 X
`3,288,920 11/1966 Baracket....
`3,588,351 G/T97L Bate ......cccsesssscccerrerersereeenee 358/149
`
`FOREIGN PATENT DOCUMENTS
`461894
`5/1973 Australia .
`1370535 10/1974 United Kingdom.............-- 358/142
`OTHER PUBLICATIONS
`
`Wireless World, vol. 81, No. 1479, pp. 498-504, Nov.
`1975, Darrington, “Wireless World Teletext Decoder |
`The Background”.
`E.B.U. Review, No. 158, pp. 163-171, Aug. 1976, Pilz,
`“Techniques for Transmitting Subtitles for Television
`Programmes in Such a Way That Their Display is Op-
`tional”.
`Mullard Technical Information Article 34, Sep. 1976.
`“Broadcast Teletext Specification”, Sep. 1976, pub. by
`BBC, IBA & BREMA.
`
`Primary Examiner—Bernard Konick
`Attorney, Agent, or Firm—Thomas A. Briody; William
`J. Streeter; Edward W. Goodman
`
`ABSTRACT
`[57]
`In a television receiver adapted for the display of a
`normal television picture and/or message information
`in which both separated synchronizing signals and lo-
`cally derived synchronizing signals are available, the
`selective use of one or the other of these two forms of
`synchronizing signals, having regard to different dis-
`play circumstances, for the picture and messageinfor-
`mation display.
`
`3 Claims, 1 Drawing Figure
`
`SYNC.
`PULSE
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`
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`SELECTOR
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`
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`
`CONVERTOR
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`
`
`COLOR
`DECODER
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`INTERFACE
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`

`U.S. Patent
`
`Dec. 15, 1981
`
`4,306,250
`
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`1
`
`4,306,250
`
`TELEVISION RECEIVER ARRANGEMENT
`HAVING MEANSFOR THE SELECTIVE USE OF
`SEPARATED OR LOCALLY GENERATED
`SYNCHRONIZING SIGNALS
`
`is a continuation, of application Ser. No.
`This
`945,064, filed Sept. 22, 1978. Now Abandoned.
`BACKGROUNDOF THE INVENTION
`
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`compared with the simple alternative of using the Jo-
`cally generated synchronising signals only when the
`separated synchronising signals are not available due to
`the absence or unsuitability of a received television
`signal.
`According to the invention, a television receiver
`arrangement of the kind referred to is characterised in
`that it includes means for causing separated synchronis-
`ing signals to be used for the television display when
`normaltelevision picture display is selected, means for
`causing locally generated synchronising signals to be
`This invention relates to television receiver arrange-
`ments of a kind suitable for use in a television transmis-
`used for the television display when message informa-
`tion display is selected and means for phase-locking the
`sion system of a character in which coded data pulses
`locally generated synchronising signals to the separated
`representing alpha-numeric text or other message infor-
`synchronising signals when a suitable video signal
`is
`mation are transmitted in a video signal in at least one
`television line in field-blanking intervals where no pic-
`being received.
`For the purposes of the present specification, a “suit-
`ture signals representing normal picture information are
`able video signal”is to be understood to be one which
`present, said television receiver arrangement including
`is not so “noise-corrupted” that coded data pulses
`data selection and acquisition means for extracting se-
`which are extracted therefrom are likely to result in an
`lectively coded data pulses from a received video sig-
`unintelligible display.
`nal, a data store for storing the extracted coded data
`In a television receiver arrangement according to the
`pulses, decoding means for producing from the stored
`invention, it has been found that by using the locally
`coded data pulses a video signal which can be used to
`generated synchronising signals for the television dis-
`cause the display onatelevision screen ofthe particular
`25
`play of message information there is the advantage that
`message information represented by the stored coded
`there tends to be less “jitter” in the display, compared
`data pulses, and oscillator means for producing locally
`with using separated synchronising signals. By phase-
`generated synchronising signals within the television
`locking the locally generated synchronising signals to
`receiver arrangement
`itself, which locally generated
`the separated synchronising signals, whenever possible,
`synchronising signals can be used for the television
`there is the further advantage that the locally generated
`display.
`synchronising signals can then also be used for syn-
`The television receiver arrangement may include
`chronisation purposes in the acquisition of coded data
`suitable television display means, or it may be adapted
`pulses from an incoming video signal.
`to feed the video signal into a separate television re-
`ceiver.
`Asa modification, means may be provided for inhibit-
`ing the use ofthe separated synchronisingsignals for the
`A television transmission system of the character
`television display when normal television picture dis-
`referred to above is described in United Kingdom pa-
`play is selected and for using instead the locally gener-
`tent specification No. 1,370,535.
`ated synchronising signals, if the received video signal
`A television receiver arrangement of the above kind
`is known from Mullard Technical Information Article
`is not suitable in that
`it
`is unacceptably ‘“noise-cor-
`rupted,” as aforesaid. This has the advantage that the
`34, dated September, 1976.
`The use of oscillator means within a television re-
`television picture display is unlikely to be degraded any
`further, but that there can now be an intelligible super-
`ceiver arrangement of the above kind to produce lo-
`imposed display on the picture display of any pre-stored
`cally generated synchronising signals is also known
`data, such as channel information as may be generated
`from German Offenlegungshrift No. 26 51 635 in which
`by a television remote control device.
`the locally generated synchronising signals are pro-
`The invention also extends to a television receiver
`duced for the television display of stored data in the
`arrangement of the kind referred to and as set forth
`absence oftelevision synchronisation normally received
`above, embodied in a television transmission system of
`(e.g. from a broadcast video signal containing synchro-
`the character referred to. Also, such a television re-
`nizing signals which can be separated out). The stored
`ceiver arrangement with the aforesaid selective use of
`data whichis for display may have been received either
`either separated or locally generated synchronising
`from a television video signal, or from a normaltele-
`signals can be adapted to cause the display of apha-
`phone transmission line. The television receiver ar-
`numeric text or other message information concurrently
`rangement described in this German Offenlegungss-
`with, or as a selectable alternative to normal picture
`chrift is also organised such that it blocks the operation
`information.
`of a television synchronising separation stage and in-
`stead produces locally generated synchronising signals
`whena received television signal falls below a predeter-
`mined threshold level.
`
`SUMMARYOF THE INVENTION
`
`The present invention is based on the premise thatin
`a television receiver arrangementof the kind referred to
`in which both separated synchronising signals and lo-
`cally generated synchronising signals can be made
`available, the selective use of one or the other ofthese
`two forms of synchronising signals, having regard to
`different display circumstances, affords considerable
`advantages in the performance of the arrangement as
`
`DESCRIPTION OF THE DRAWING
`
`In order that the invention may be morefully under-
`stood reference will now be made by way of example to
`the accompanying drawing in which the single FIG-
`UREis a block diagram ofa television transmission
`system ofthe character referred to embodyinga televi-
`sion receiver arrangement according to the invention.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`The drawing showsa television transmission system
`of the character referred to having a television receiver
`
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`arrangement for displaying selectively either a televi-
`signal VSis divided into different pages of information,
`sion picture which is produced from picture informa-
`and that each page is for display as a whole on the
`tion in a norma] broadcast or cable television video
`screen of the picture tube 9 with the coded data pulses
`signal, or alpha-numeric text or other message informa-
`representing each page of information being repeated
`tion which is produced from coded data pulses which
`periodically with or without updating of the informa-
`are transmitted in the video signal in vertical- or field-
`tion. It is further assumed that each page of message
`blanking intervals thereof. The possibility can also exist
`information is identified by means of a unique page
`for displaying such message information concurrently
`address code which is included in the coded data pulses
`with a television picture, for instance as sub-titles or
`and defines the page number. A codeselector circuit 16
`captions which are superimposed on the television pic-
`controls the particular coded data pulses that are ac-
`ture. The television receiver arrangement
`is also
`quired by the data acquisition circuit 15 at any time.
`adapted to receive and display message information
`(This controlis indicated by a broad-narrow connection
`received from another source, such as Viewdata infor-
`representing the presence of n parallel channels which
`mation as transmitted over a telephoneline in the exper-
`form an n bit channellink for carrying n bits of informa-
`imental British Post Office Viewdata System (see Wire-
`tion required for data selection—other groups of paral-
`less World, February-May, 1977).
`lel channels forming multi-bit channellinks in the televi-
`The incoming television video signal VS appears at
`sion receiver arrangement are represented similarly as
`an input lead 1 of the television receiver arrangement
`m, p, a, r, and s numbersof channels andbits of informa-
`via its front end 2 which comprises the usual amplify-
`tion).
`.
`ing, tuning,i.f. and detector circuits. The front end 2 is
`The acquired coded data pulses are clocked serially
`assumed to be coupled to a television transmitter 3 via a
`into the data acquisition circuit 15 by the clock pulse
`conventional over-air broadcast or cable transmission
`output from the clock pulse generator 13. From the data
`link 4. The transmitter 3 includes in known manner
`acquisition circuit 15, the acquired coded data pulses
`means for producing television picture information,
`are fed to a data store 17 over an m-bit channel link, m
`means for producing alpha-numeric text or other mes-
`bit bytes being required for each character (or other
`sage information, and further means for generating the
`item of information) contained in the message informa-
`appropriate composite television video signal contain-
`tion, where m=7, for example.
`ing picture signals representative of the picture informa-
`The data store 17 can store a complete page of mes-
`tion, and coded data pulses representative of the mes-
`sage information.
`In a typical Teletext
`transmission,
`sage information, together with the usual synchronis-
`each page of message information would contain up to
`ing, equalizing and blanking signals which are necessary
`2-
`.owsof characters, with each row containing up to
`for the operationofthe television receiver arrangement.
`+J characters. Thus,
`in order to identify the different
`For the normalpicture display in the television re-
`characters of a page,it is furthermore assumedthat the
`ceiver arrangement,
`the received video signal VS is
`coded data pulses also include an address code for each
`applied to a selector circuit 5 which includes a selector
`character, this address code employing r bits and being
`switch 6. When the switch6 is closed, the video signal
`fed to the data store 17 from the data acquisition circuit
`VSis applied to a colour decoder 7 which produces the
`15 over an r-bit channel link.
`R, G and B componentsignals for the picture display,
`'
`In view of the restricted transmission time which is
`these component signals being applied via a video inter-
`available for transmitting the coded data pulses repre-
`face circuit 8 to the red, green and blue gunsof a colour
`senting message information, for instance, sufficient
`television picture tube 9. Timebase circuits 10 for the
`time to transmit
`the coded data pulses for only one
`tube 9 receive the usual line and field synchronising
`character row duringatelevisionline in the field-blank-
`pulses LS and FS from a sync. separator circuit 11
`ing interval, character data for a page of messageinfor-
`which extracts these synchronising pulses from the
`mation has to be stored row-by-row in the data store 17
`incoming video signal VS, or from locally generated
`over a relatively large number oftelevision fields. This
`synchronising signals, as will be described.
`storing of character data row-by-row in the data store
`17 is under the control of the address codes received
`Coded data pulses representing message information
`in the video signal VS do notaffect the picture display
`from the data acquisition circuit 15 over the r-bit chan-
`because they occur in one or morelines in the field-
`nel link. Coded data pulses can also befed into the store
`blanking interval whenthere is no picture display. Of 50
`17 over an s-bit channel link from Viewdata inputcir-
`the lines occurring in the field-blanking interval, most
`cuits 18, these latter coded data pulses being received
`could be used to transmit coded data pulses represent-
`via a telephone (not shown) from a telephoneline 19.
`ing message information. However, in the experimental
`Another message information source from which the
`BBC/IBATeletext System for whichthe present inven-
`data store 17 can receive coded data pulses may be,for
`tion was originally conceived, it is proposed at present
`instance, a video cassette player.
`to restrict such use to lines 17/18 of even fieldsandlines
`Thetelevision receiver arrangement further includes
`330/331 of odd fields of the 625 line broadcasttelevision
`decoding means comprised by a character generator 20
`system used in the United Kingdom. (See “Broadcast
`and a parallel-to-serial convertor 21. The character
`Teletext Specification”, September 1976, published
`generator 20 is responsive to the character data stored
`jointly by the British Broadcasting Corporation, Inde-
`in the data store 17 to produce character generating
`pendent Broadcasting Authority and British Radio
`data which can be used to derive whatis effectively a
`Equipment Manufacturers’ Association).
`new picture signal for displaying the characters repre-
`The video signal VS on the input load 1 is also ap-
`sented by the stored character data. As mentioned pre-
`plied to data selection and acquisition means comprising
`viously, different characters can be represented by re-
`a data extractor circuit 12, a data clock pulse generator
`spective m-bit bytes. The bits of each byte are fed in
`13, a data acceptor gate 14 and a data acquisition circuit
`parallel from the data store 17 to the character genera-
`15. It is assumed that the message information repre-
`tor 20 as p-bit bytes. A character format for characters
`sented by the coded data pulses contained in the video
`to be displayed can be a co-ordinate matrix composed of
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`to generate the inhibiting signal IS. When the separated
`discrete elements arranged in rows and columns, this
`line synchronizing pulses are “clean”,
`the resulting
`format being derived from a “read-only” memory
`“clean” pulses from the AND-gate will cause an in-
`which serves as the character generator 20 and which
`crease in the output voltage of the integrator which
`provides bits of character generating data in rows and
`voltage is now above the threshold in the threshold
`columns, one row at a time. Since the character generat-
`detector which then terminates the signal IS from the
`ing data is required as a modulation ofa video signal in
`Schmitt trigger circuit.
`order to produceselective bright-up of the screen of the
`Considering now the selective usage of separated
`picture tube 9 to achieve character display, the charac-
`synchronising signals and locally generated synchronis-
`ter generating data is produced serially (as 1's and 0's)
`ing signals,
`the incoming video signal VS is further
`by using the convertor 21 to convert each row ofbits of
`applied to a sync. pulse separator 24 andto an electronic
`data read out from the character generator 20 (e.g.
`switch 25 (which for the sake of simplicity is repre-
`a=5) into serial form.
`sented by a mechanical changeover contact having
`In order to effect character display on the screen of
`fixed terminals 26 and 27 and a changeover contact 28).
`the picture tube 9 using standard line and frame scans,
`The separated sync. pulses produced by the sync. pulse
`the logic of the television receiver arrangement in re-
`separator 24 are applied to a phase-locked oscillator 29
`spect of character display is so organised that for each
`which drives a timing chain 30, and to one input of the
`row of characters to be displayed,all the characters of
`signal quality arrangement 23. The timing chain 30
`the row are built uptelevision line-by-television line as
`provides appropriate clock and timing pulses to the data
`a whole, and the rows of characters are built up in
`succession. It takes a numberoftelevision lines to build
`acquisition circuit 15, the code selector circuit 16, the
`data store 17, the Viewdata input circuits 18 and the
`up one row of characters. In the first television line
`character data from the data store 17 to the character
`character generator 20. The timing chain 30 also drives
`synchronising pulse generator 31 which produces the
`generator 20 would cause the latter to produce charac-
`locally generated synchronising signals in response to
`ter generating data with respect to thefirst row of dis-
`crete elements for the first character of the row, then
`the output received by it from the timing chain 30.
`with respectto the first row ofdiscrete elements for the
`Locally generated line sync. pulses are applied via a
`second character, and so on for the successive charac-
`lead 32 to a second input of the signal quality arrange-
`ters of the row. In the secondtelevision line, character
`ment 23. Also, these locally generated line sync. pulses
`are combined in a gate 33 with field sync. pulses which
`generating data with respect to the second row ofdis-
`crete elements for each character of the row would be
`are produced by the generator 31 on a lead 34, and
`which are synchronised with the incoming field sync.
`produced in turn, and so on for the remaining television
`lines concerned.
`pulses supplied by the sync pulse separator 24 via an
`inhibiting gate 36. The outputof the gate 33 is applied to
`The output from the convertor 21 is applied to a
`the switch 25.
`colour coder 22 which produces R’, G' and B’ compo-
`A user control unit 35, which may be a hand-held
`nent signals for character display,
`these component
`remote control device of any suitable known form,
`signals being also applied to the video interface circuits
`controls channel selection and adjustment, etc., at the
`8. The colour coder 22 can be controlled (in a manner
`front end 2 and selector switch 5; and also the code
`not shown)byselected items of the character data in the
`selector 16 and the Viewdata circuits 18 for the selec-
`data store 17 to provide a controlled colour display. Of
`tion of either form of message information. When a
`course, black-and-white picture and character display is
`normal picture channelhas been selected and the broad-
`also possible, in which event the colour decoder 7 and
`colour coder 22 would be omitted.
`cast video signal concerned is being received, a “picture
`on” signal PO produced by the user control unit 35
`includes, as
`The television receiver arrangement
`causes the switch 25 to assumethe position shown with
`aforesaid, as part of the data selection and acquisition
`contact 28 engaging terminal 26 so that the incoming
`means, a data acceptor gate 14. The coded data pulses
`video signal VS is applied to the sync. separatorcircuit
`extracted from the incoming video signal VS by the
`11. Asaresult, separated synchronising signals are used
`data extracter circuit 12 are applied to the data acquisi-
`to control the time bases 10.
`tion circuit 15 via this acceptor gate 14 which is con-
`When Teletext or Viewdata message information is
`trolled by a signal quality arrangement 23. This arrange-
`selected, the signal PO is terminated and the switch 25
`ment 23 is responsive to apply an inhibiting signal IS to
`then assumes the position in which contact 28 engages
`the data acceptor gate 14to inhibit the acceptance for
`terminal 27 so that now the locally generated synchro-
`storage of coded data pulses when a predetermined
`nising signals from the pulse generator 31 are applied to
`signal-to-noise ratio in the incoming video signal VS is
`the sync. separator circuit 11. As a result, the locally
`exceeded. The arrangement 23, which may comprise
`generated synchronising signals are now used to control
`the serial combination of an AND-gate, an integrator, a
`the time bases 10. In each of these two instances, the
`threshold detector and a Schmitt trigger circuit, deter-
`operation of the time bases 10 is synchronised with the
`mines an acceptable signal-to-noise ratio by comparing
`incoming video signal VS,in the first instance directly
`line synchronizing pulses, separated from the received
`and in the second instance because the oscillator 29 is
`video signal, with locally generated “clean” line syn-
`phase-locked to the incoming video signal VS.
`chronizing pulses, both of which are applied to the
`If the signal quality becomes unacceptableorthere is
`AND-gate of the arrangement 23 with the inhibiting
`no incoming video signal, then the inhibiting signal IS
`signal IS appearing at the output of the Schmitt trigger
`from the signal quality arrangement 23 unlocks the
`circuit. Noise, sufficient to cause break-up of the sepa-
`oscillator 29 to allow it to free-run, and alsoinhibits the
`rated line synchornizing pulses, will cause a similar
`application ofthefield sync. pulses to the generator 31
`break-up in the output of the AND gate. By selecting a
`by activating the inhibiting gate 36. The locally gener-
`suitable threshold in the threshold circuit, the voltage
`ated synchronising signals are thus still produced but
`output from the integrator will trip the threshold detec-
`are not synchronised with any incoming video signal.
`tor which thereupon causes the Schmitt trigger circuit
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`When a video signal is present, the signal IS also, of
`course,
`inhibits the acceptor gate 14 to prevent
`the
`reception and storage of noise-corrugated coded data
`pulses.
`As a modification the switch 25 may also be con-
`trolled by the inhibiting signal IS such that even when
`the “picture on” signal PO is present locally generated
`synchronising signals are selected in preference to sepa-
`rated synchronizing signals when the signal quality is
`sufficiently bad to cause the productionofthe inhibiting
`signal
`IS. This permits an intelligible superimposed
`display on the picture display of any prestored data,
`such as channelinformation as may be generated by the
`unit 35.
`Weclaim:
`1. A television receiver arrangement of a kind suit-
`able for use in a television transmission system of a
`character in which coded data pulses representing al-
`pha-numeric text or other message information are
`transmitted in a video signal in at least one television
`line in field-blanking intervals where no picture signals
`representing normal picture information are present,
`said television receiver arrangement including means
`for separating synchornizing signals from said video
`signal, data selection and acquisition means for extract-
`ing selectively coded data pulses from a received video
`signal, a data store for storing the extracted coded data
`pulses, decoding means for producing from the stored
`coded data pulses a video signal which can be used to
`cause the display on a television screen of the particular
`message information represented by the stored coded
`
`0
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`data pulses, the oscillator means for producing locally
`generated synchronising signals within the television
`receiver arrangement
`itself, which locally generated
`synchronising signals can be used for the television
`display; wherein said television receiver arrangement
`further comprising meansfor selectively switching be-
`tween a normaltelevision picture display and said mes-
`sage information display, means for causing said sepa-
`rated synchronising signals to be used forthe television
`display when normal
`television picture display is se-
`lected, meansfor causing locally generated synchronis-
`ing signals to be used for the television display when
`message information display is selected, means for de-
`tecting a suitable video signal, and means for phase-
`locking the locally generated synchronising signals to
`the separated synchronising signals when a suitable
`video signal is being received.
`2. A television receiver arrangement as claimed in
`claim 1, wherein said selectively switching means is
`adapted to cause the display of alpha-numeric text or
`other message information concurrently with, or as a
`selectale alternative to, normal picture information.
`3. A television receiver arrangement as claimed in
`claim 1, which further comprises means for inhibiting
`the use of the separated synchronizing pulses for the
`television display when normaltelevision picture dis-
`play is selected and for using instead the locally gener-
`ated synchronizingsignals if the received video signalis
`not suitable.
`*
`*
`*
`*
`*
`
`45
`
`50
`
`55
`
`65
`
`PMC Exhibit 2105
`Apple v. PMC
`IPR2016-01520
`Page 6
`
`PMC Exhibit 2105
`Apple v. PMC
`IPR2016-01520
`Page 6
`
`