(11)
`(15)
`United States Patent
`
` Ciciora [45]
`
`4,233,628
`Noy. 11, 1980
`
`data with Comments on Compatability”, LEEE Trans-
`[54] NTSC RECEIVER USEABLE WITH
`action on Consumer Electronics, vol. CE-25, No. 3, Jul.
`TELETEXT/VIEWDATA INFORMATION
`1979, pp. 235-245.
`Inventor: Walter S. Ciciora, Park Ridge,III.
`[75]
`Daniels, “Wireless World Teletext Decoder”, Wireless
`;
`.
`.
`
`[73] Assignee: Zenith Radio Corporation, Glenview,—World, vol. 81, No. 1480, pp. 563-566, Dec. 1975.
`Ill.
`Kiver, Television Simplified,
`\7th Edition, 1973, Van
`[21] Appl. No.: 2,523
`Nostrand Reinhold Company, pp. 346-347.
`[22] Filed:
`dam ET, 2979
`Primary Examiner—John C. Martin
`
`(SU) Int, C13 cece HO4N 7/08; HO4N 3/22~—Attorney, Agent, or Firm—Thomas E. Hill
`[52] USi@loccssccscccssscnesassaccccnatietegs 358/147; 358/180;
`358/142; 358/85; 315/395
`[58] Field of Search............00 358/147.85, 140, 180,
`358/142, 146; 315/395: 340/731, 750, 723, 748:
`Meee TN.
`
`[57]
`ABSTRACT
`:
`st
`-
`A Teletext equipped NTSC television receiver system
`includes means for compressing theraster in the vertical
`direction in response to 625-line formatted Teletext
`signals to display normally overscanned horizontallines
`on the television viewing screen. Thus 625-line format-
`ted Teletext material may be used directly with NTSC
`
`4,161,728—T/D9T9 Uma wa.sececeneeseeersneereneeneneeneeee 358/85 receivers.
`OTHER PUBLICATIONS
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`Ciciora et al., “An Introduction to Teletext and View-
`
`13 Claims, 2 Drawing Figures
`
`
`
`DEMODULATOR
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`
`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`Page 1
`
`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`Page 1
`
`

`

`U.S. Patent
`
`Nov. 11, 1980
`
`Sheet 1 of 2
`
`4,233,628
`
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`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`Page 2
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`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`Page 2
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`
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`U.S. Patent
`
`Nov. 11, 1980
`
`Sheet 2 of 2
`
`4,233,628
`
`A/D VIDEO
`
`PROCESSOR
`
`TELETEXT
`TYPE
`RECOG.
`
`TELETEXT
`
`9
`
`TEXT
`
`VIDEO
`INPUT
`VERT. RAMP
`
`SLOPE CONTROL
`
`
`i TIMING
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`L. MEMORY
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`TELETEXT | TIMING
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`
`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`Page 3|aitIiETETSETESARE,EKAAF:
`
`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`Page 3
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`

`1
`
`4,233,628
`
`2
`request and presentation of the information. To mini-
`mize delay popular features may be transmitted fre-
`quently. On the other hand, pages of limited interest
`may be transmitted infrequently. Since the receiver has
`the facility for storing the desired control and data
`signals it is feasible to store infrequently transmitted, but
`desired material at a time when the receiver is not being
`used (i.e. during the early morning hours) which would
`then be ready for presentation without delay at a later
`time.
`There are various Teletext-like services in operation
`in England, Europe, and the United States which sup-
`ply specialized information to subscribers with properly
`equipped television receivers. The specialized informa-
`tion includes stock market quotations, instructural pro-
`grams, newscasts, weather information, directories for
`variousactivities, sports results, etc.
`-
`In practice a viewer with a Teletext equipped re-
`ceiver would request, via a keyboard or other suitable
`selection mechanism, display of a magazineindexlisting
`of Teletext
`information available by page and time
`code, if used. He would then select the page or pages of
`material he wished to view on his receiver.
`As mentioned the digital data includes synchronizing,
`control and address information for determining paging
`and format of the information when displayed on the
`screen. The receiver includes means selecting and stor-
`ing the desired digital information, a read only memory
`for storing the necessary character information: means
`addressing the read only memory under control of the
`stored digital information and means controlling the
`address means for proper synchronization and framing
`the character information being read out of the charac-
`ter memory. The Teletext informationis supplied to the
`receiver video section for proper display on the viewing
`screen.
`The term Teletext is generally considered to refer to
`over-the-air transmission of text information during the
`vertical
`interval. An obvious alternative method for
`transmission of such information is to use conventional
`telephone lines. When this is done it
`is generally re-
`ferred to as Viewdata.It will be appreciated that, as far
`as the present invention is concerned, it matters not
`whether Teletext or Viewdata information is being
`received. Regardless of whether information transmis-
`sion occurs via conventional telephonelines as in View-
`data or during the vertical interval via television video
`signal as in Teletext, the present invention,since it in-
`volves only the display of such information, has equal
`applicability.
`In the British 625 line system a Teletext page format
`is 40 characters per line with the height of each row of
`characters being 10 lines and a page consisting of 20-24
`rows. A 625 line system (312/313 lines per frame) of
`course contains more “usable lines” than a 525 line
`NTSCsystem. In both systems the unusable lines are
`accounted for by a combination of overscanning and
`processing time required for the video display. Teletext
`information which is coded for the British television
`system has a format requiring 240 usable lines, whichis
`greater than the number of normally visible lines in an
`NTSC system.
`The United States presently has no standard for Tele-
`text material. There is a great deal ofinterest in enabling
`any U.S. Teletext system to use material formatted for
`the British standards with minimum modification. How-
`
`NTSC RECEIVER USEABLE WITH
`TELETEXT/VIEWDATA INFORMATION
`
`BACKGROUNDOF THE INVENTION
`
`5
`
`This invention relates generally to Teletext Commu-
`nication Systems and specifically to means for utilizing
`Teletext information formatted for 625 line displays in
`Teletext-equipped NTSCtelevision receivers.
`DESCRIPTION OF THE PRIOR ART
`
`Teletext denominates a new and rapidly growing
`television communication technique which uses the
`vertical blanking interval of a television broadcast sig-
`nal for transmission of text and graphical information.
`Systems are already operational in England for trans-
`" mitting pages of formatted text material, in digital form
`on lines 17, 18, 330 and 331 of their 625 line system.
`Receivers equipped with appropriate decoders and
`memories are capable of decoding instructions for any
`page ofthe transmitted text information and displaying
`it on their viewing screens.
`The transmitted signal includes character or symbol
`identification in coded form, but not the information for
`actually generating the character or symbol display.
`The character generation meansare in the receiver and
`include a read only memory (ROM) and means for
`“reading” the memory for character generation in re-
`sponse to a characteridentification input. For example
`if the decodedsignalcalls for character “A”, the ROM
`locations are appropriately addressed to produce the
`required information to form an “A” at the desired
`location on the television screen. Thus the receiver
`includes a random access memory (RAM)for storing
`the decoded digital line signals and a ROM for actual
`generation of the character or symbol information. The
`ROM maybe microprocessor controlled for addressing
`the memory in accordance with the input character
`identification or conventional logic means may control
`the addressing.
`Despite some limitations, such as the access time for
`information retrieval, the potential of Teletext Commu-
`nication is enormous. In the British “ORACLE” system
`for example, the Teletext information consists of bursts
`of digital signals on the aforementioned lines. Each
`line-of-data signal contains 360 bits arranged in 45 Bytes
`of eight bits each. Thefirst five Bytes are used for syn-
`chronizing, control and address purposes while the
`remaining 40 are used to denote characters. Each char-
`acter is allocated 8 bits and a page consists of 24 rows of
`40 characters.
`With two data lines per field four pages of text may
`be transmitted each second. The pages are grouped into
`magazines of up to 100 pages each. (Up to eight such
`magazines may be provided.) A control code and ad-
`dress code are used to select and display desired infor-
`mation with every data line containing a coded maga-
`zine number and row address.
`A special 4 digit time code enables up to 3,200 differ-
`ent texts for each “‘page” to be transmitted and selected
`through a time-division-multiplex approach. The time
`codeis not necessarily related to clock time but Is used
`to greatly expand the magazine pages. For example a
`page may be selected by its magazine number and page
`number or by the above numbers and a time code.
`Since the information is transmitted serially, it may
`take a little while for a particular page to be transmitted
`and the viewer may experience some delay betweenhis
`
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`4,233,628
`
`3
`ever, none of the systems presently in use in the United
`States are capable of using such material.
`The majordifficulty is, that to retain the definition of
`the British system, 10 horizontal lines for the characters
`and the number ofrows in the page would result in the
`upper and lowerportions of the text material being off
`the screen because in the NTSCsystem thereis a maxi-
`mum of 240/241 usable lines, with some of these being
`lost due to overscanning which is a necessity for mass
`produced television receivers. To reformat the British
`Teletext material for use in an NTSC system of, for
`example, only 20 rows of 10-line characters would thus
`require humanintervention. If the human element were
`not needed, it would only be necessary to add British
`data decoders to derive the proper controlsignals and
`would only impose a minor capital expenditure on
`broadcasters.
`:
`One suggested solution is to adopt a United States
`page format requiring only 9 horizontallines per char-
`acter. This would permituse of British Teletext material
`without
`reformating. However a substantial
`loss of
`character definition would result and consequentlyit is
`not an acceptable solution.
`One system envisioned by the invention would essen-
`tially adopt
`the page format of the British system,
`namely 24 rows of 10-line characters, (with 40 charac-
`ters per scan line) and compress the television raster to
`display all usable lines on the viewing screen. Thus each
`framein a field would have 240/ 241 lines displayed on
`the receiver screen. Another system envisioned by the
`invention would utilize raster-compression only for
`British formatted Teletext material and would process
`anddisplay locally produced Teletext material in accor-
`dance with whatever standardis ultimately adopted in
`the United States. This latter system would involve
`having a separate ROM for British formatted charac-
`ters, decoding logic to determine when British Teletext
`material was being received and switch means for auto-
`matically selecting the appropriate apparatus in accor-
`dance with the outputof the decoding logic.
`OBJECTS OF THE INVENTION
`Anobject ofthis invention is to provide a novel and
`improvedtelevision receiver.
`A further object of this invention is to provide a
`novel Teletext equipped television receiver.
`
`50
`
`SUMMARYOF THE INVENTION
`In accordance with the invention a Teletext equipped
`NTSCtelevision receiver having a normal video dis-
`play capability of 200 usable horizontal lines per field
`includes signal synthesis means for converting digital
`signals received during the vertical retrace interval
`having a format of approximately 240 horizontal scan
`lines per field and meansforaltering the picture tube
`raster to enable said signal synthesis means to make a
`video display of said digital signals less without alter-
`ation of the signal synthesis means.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG.
`1 is a block diagram of a Teletext equipped
`NTSCtelevision receiver in accordance with one as-
`pect of the invention.
`FIG. 2 is a block diagram of a Teletext equipped
`NTSCtelevision receiver in accordance with another
`aspect of the invention.
`
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`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`’ Referring to FIG. 1, a television tuner and IF ampli-
`fier 10 is coupled to a video detector 12 which supplies
`an audio circuit 14, a video amplifier 18, a color demod-
`ulator 20, a horizontal deflection circuit 22 and a verti-
`cal ramp generator 24. Audio circuit 14 includes con-
`ventional detection and amplification circuitry and is
`coupled to a speaker 16 for reproducing the audio ac-
`companimentofthe broadcasttelevision signal. A pair
`of conventional deflection coils 34 are mounted on the
`picture tube and are supplied by horizontal deflection
`circuit 22 and vertical deflection circuit 26. The input of
`the vertical deflection circuit 26 is supplied from verti-
`cal ramp generator 24.
`Unlike conventional television receivers, the outputs
`of color demodulator20 andthe output of video ampli-
`fier 18 are supplied to an electronic switch 28. Also, the
`outputof video detector 12 supplies an A/D (analog to
`digital) video processor 54. The luminance signal Y and
`color difference signals R-Y, B-Y and G-Y outputs of
`electronic switch 28 are combined into R, B, and G
`signals and supplied to a summer and amplifier 30 which
`feeds appropriate elements in an electron gun structure
`(not shown)in a picture tube 32. With the exception of
`the electronic switch, the summer and amplifier and the
`video output
`to A/D video processor 54,
`the color
`television receiver thus described will be seen to be
`conventional.
`A/D video processor 54 accepts the serial digital
`Teletext information in the vertical retrace interval of
`the broadcast television signal and supplies it to a Tele-
`text data control 52 which accesses a memory RAM 58.
`Memory RAM 58,in turn, accesses a Teletext ROM 60.
`A/D video processor 54 is intercoupled with a timing
`chain circuit 56 which also accesses Teletext ROM 60.
`Teletext data control 52 and Teletext ROM 60are also
`accessed by a keyboard 50 by means of which the
`viewer mayselectdesired pages of Teletext information
`and system operating modes. In general these modes are
`Television, Teletext, and Mixed—thelatter comprising
`Teletext information superimposed upon normal televi-
`sion video.
`The outputs of ROM 60 include a blankingsignal, a
`so-called text signal and RGBsignals, all of which are
`supplied to electronic switch 28, The RGBsignals from
`the Teletext ROM are offixed value and the number of
`colors reproducible is accordingly limited. The text
`signalis a form of blanking signal and whenthe receiver
`is operating in the Teletext mode, blanks out all video
`except where characters are to appear.
`in-
`As thus far described the Teletext equipment
`cluded in dashed-line box 62 is conventional and the
`circuit arrangementforutilizing the Teletext equipment
`in the television receiver is also well-known in the Tele-
`text art. For example see Mullard Technical informa-
`tion Note 54 (Mullard Ltd., Mullard House, Torrington
`Place, London WCIE7HD) in which the Teletext
`equipmentis described in greatdetail. The differencein
`the present circuit is in the lead connecting Teletext
`data control 52 to vertical ramp generator 24, over
`whichis supplied a vertical ramp slope control signal.
`Whenthe television receiver is operated in the Teletext
`mode,theslope of the vertical rampis changed to affect
`the vertical deflection circuits in a compressive manner,
`that is, substantially all of the horizontal lines of each
`
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`IPR2016-01520
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`_
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`6
`5
`and thetelevision receiver) to control functioning of the
`frame are displayed on the television viewing screen of
`ramp control relay or electronic switch in the vertical
`picture tube 32.
`information is
`As previously mentioned, Teletext
`ramp generator. Such an arrangement is believed well
`within the skill of the art.
`included during the vertical retrace interval of a stan-
`dard television broadcast signal and appears onadesig-
`In accordance with a second aspectofthe invention,
`nated horizontal line in either or both frames. After
`shown in FIG. 2, the system envisions two different
`processing in A/D processor 54, timing control infor-
`types of Teletext material being available for use on an
`mation is supplied to timing chain circuit 56 which
`NTSCtypetelevision receiver. For those Teletext pro-
`derives the essential timing information to enable con-
`grams specifically formatted for an NTSC type system
`struction of the selected Teletext display. The informa-
`no raster change would be required and, consequently,
`tion is read into RAM 58 undercontrol of the keyboard
`no raster change is involved. However, compatibility
`and the Teletext data control, and in conjunction with
`with Teletext information formatted for 625-line sys-
`timing chaincircuit 56, accesses ROM 60 to synthesize
`tems is maintained by using the raster compression ap-
`the display of symbols and figures in accordance with
`proach described for FIG. 1. In its simplest form a
`the Teletext information selected. ROM 60 comprises
`common A/D processor, memory RAM and Teletext
`all necessary information for complete generation,
`ROMandseparate Teletext data controls and timing
`under control of the memory RAM andtimingsignals,
`chain generators and provided. The keyboard accesses
`of the various characters and symbols utilized in the
`both data controls, each of which is associated with the
`Teletext system. As a gross analogy, the ROM may be
`timing chain generatorforits specific Teletext system,
`thought of as the typewriter and the remainder of the
`directly feeding the common memory RAM.A Tele-
`Teletext equipment considered the typist.
`text type recognition circuit 64 is provided between the
`For example, if the character A is designated by the
`A/D processor 54 and Teletext data controls 66 and 76.
`memory RAM, the timing signals cause a sequential
`For NTSC formatted Teletext signals recognition cir-
`readout of appropriate memory locations in the ROM.
`cuit 64 activates data control 66 and timing chain 68
`After the requisite number of lines, (10 in the British
`whereas for a 625-line formatted signal the recognition
`system),
`the complete character A will have been
`circuit activates data control 72 and its corresponding
`formed. The RGB Teletext signals energize the guns in
`timing chain 74. The net result is that the character
`the picture tube via electronic switch 28—so that the
`generation ROMis accessible to control by thedifferent
`appropriate character A of propercolor is reproduced.
`timing circuits. Since NTSC formatted Teletext signals
`It will be appreciated that the Teletext video informa-
`would not contain as much information, only part of the
`tion must be synchronized with the deflection system
`ROMis addressed. For example if only 200 lines were
`such that the sequentially generated video information
`used in an NTSC Teletext system the ROM would be
`has the proper relationship to develop the characters.
`accessed only during those 200 lines. In the 625-line
`In accordance with a first aspect of the invention
`formatted signal, however, the ROM would beinterro-
`Teletext data control 52 supplies a vertical ramp slope
`gated for a full 240 lines to display the larger formatted
`control signals to vertical ramp 24 to cause the vertical
`material. (The raster of the television receiver is com-
`ramp to rise at a slower rate and thus compress the
`pressed to enable full display of the 240lines for 625-line
`vertical size of the produced display. This compression
`formatted signals.)
`results in the normally unused (and overscanned) hori-
`The inventive concept uses well known hardware
`zontal scan lines being reproduced on the face of the
`and techniques. Raster expansion is well-known in the
`screen and information on these scan lines is therefore
`art, both in one and two dimensions. See for example
`visible.
`It will be noted that the horizontal/vertical
`U.S. Pat. No. 4,028,726 to Thomas Argy, and assigned
`aspect ratio of the displayed Teletext information will
`to Zenith Radio Corporation. Raster compression
`be affected with the vertical dimension being approxi-
`would readily be obtainable with an obvious modifica-
`mately 10% shorter than normal. However,the benefit
`tion to produce a slowervertical ramp. While the hori-
`ofbeing able to utilize 625-line formatted Teletext infor-
`zontal expansion circuit of the Argy Patent may be
`mation far outweigh this slight degradation in aspect
`ignored in the present embodiments, it may be desirable
`ratio—especially since the vast majority of such infor-
`in some cases to compress the entire raster. This may be
`mation is textual. It is to be noted that in this aspect of
`readily accomplished by supplying a change signal to
`the invention Teletext information formatted specifi-
`the horizontal ramp generator from the Teletext data
`cally for NTSC Teletext-equipped receivers would also
`control. This is considered to be an obvious modifica-
`be subject to raster compression.
`tion and well within the skill of those working in theart.
`Development and implementation of a ramp control
`Similarly in the second aspect of the invention the Tele-
`signal is readily accomplished. For example,
`in most
`text recognition circuit design, once the specifications
`television receivers a potentiometer is incorporated in
`are known for the NTSC Teletext system format,
`the vertical ramp circuit for adjusting the vertical size
`should be straightforward.
`Indeed, and recognition
`of the video display. This potentiometer may easily
`circuit need only be activated when 625-line formatted
`bridged by a suitable resistor by means of a relay or
`Teletext information is received—in all other situations
`electronic switch to change the effective resistance in
`the NTSC format being activated. The recognition
`the potentiometer circuit
`in response to the control
`circuit may simply consist of a tuned circuit which
`signal and result in shrinking the raster on the television
`responds to the synchronizing signal
`in the received
`screen. The control signal is obtainable from the Tele-
`Teletext information.
`text circuitry and may conveniently take the form of a
`Consequently, anyoneskilled in the art and familiar
`simple logic potential. The Teletext circuitry includes a
`with the inventive concept expressed in these specifica-
`framing code detector which is responsible for deter-
`tions and claims and embodied in the drawings can
`mining when Teletext
`information is received. The
`readily construct a compatible Teletext system. Fur-
`output of this detector may be used (with suitable alter-
`ther, obvious modifications may be made without de-
`ation for level changes between the Teletext circuitry
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`-
`parting from the scope of the invention as described in
`the claims.
`Whatis claimed is:
`1. An NTSCtelevision receiver capable of normally
`displaying approximately 200 horizontally lines of
`video information perfield including;
`signal synthesis means for generating Teletext video
`information from coded digital signals received
`during the vertical intervals of normal television
`broadcastsignals, said Teletext information having
`a format embracing approximately 240 horizontal
`scan lines per field; and
`raster control means for altering the raster of said
`television receiver to display more than the normal
`number of horizontal lines and thereby enable di-
`rect use of said Teletext information.
`2. The television receiver of claim 1 wherein said
`raster control means constricts the raster of said re-
`ceiver to display substantially all horizontal lines on the
`receiver screen.
`3. The television receiver of claim 2 wherein thereis
`further included:
`switch means operable to selectively place the re-
`ceiver in a normal video presentation mode and a
`Teletext presentation mode; and
`means activating said raster control means when said
`receiveris in said Teletext presentation mode.
`4. The television receiver of claim 3 where said raster
`is compressed only in the vertical direction.
`5. In combination in a television receiver:
`signal synthesis means capable of converting first
`digital signals obtained during the vertical intervals
`of normal NTSC 525 line television broadcastsig-
`nals into a Teletext video display, said first digital
`signals having a format of approximately 200 us-
`able horizontal scan lines per field; and
`means for making a Teletext display from second
`digital signals obtained during said vertical inter-
`vals, said second digital signals having a vertical
`format of approximately 240 horizontal scan lines
`per field, including
`raster control meansfor altering the receiver raster to
`enable display of the video corresponding to said
`
`8
`second digital signals without alteration of said
`signal synthesis means.
`6. The combination of claim 5 wherein said raster
`contro] means operate to compress the vertical expanse
`of said raster.
`7. The combination of claim 6 wherein said receiver
`includes a normal video and Teletext video mode; and
`means for manually selecting the operating mode for
`said receiver.
`8. The combination of claim 7 further including
`switch means operable whensaid receivers in said Tele-
`text mode for activating said raster control means in
`response to said second digital signals.
`9. An NTSCtelevision receiver capable of normally
`displaying approximately 200 horizontal lines of video
`information perfield including:
`signal synthesis means for generating video informa-
`tion from coded audio digital signals, said video
`information having a format embracing approxi-
`mately 240 horizontal scan lines per field; and
`raster control means for altering the raster of said
`television receiver to display more than the normal
`number of horizontal lines and thereby enable di-
`rect use of said video information.
`10. The television receiver of claim 9 wherein said
`coded audio digital signals represent Viewdata video
`information.
`11. The television receiver of claim 9 wherein said
`raster control means constricts the raster of said re-
`ceiverto display substantially all horizontal lines on the
`receiver screen.
`12. The television receiver of claim 9 wherein said
`raster is compressed only in the vertical direction.
`13. An NTSCtelevision receiver capable of normally
`displaying approximately 200 horizontal lines of video
`information per field including:
`signal synthesis means for generating video informa-
`tion from codeddigital signals, said video informa-
`tion having a format embracing approximately 240
`horizontal scan lines per field; and
`raster control means for altering the raster of said
`television receiver to display more than the normal
`numberof horizontal lines and thereby enable di-
`rect use of said video information bysaid television
`receiver.
`*
`*
`*
`*
`*
`
`5
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`5
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`30
`
`40
`
`45
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`55
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`65
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`Page 7
`
`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`
`PMC Exhibit 2101
`Apple v. PMC
`IPR2016-01520
`Page 7
`
`