`
`PS SPECIAL HUME
`ELECTED/MUS
`
`High-
`resolution TV
`— here come wide-screen
`crystal-clear pictures
`
`
`
`New video components
`speed TV systems that
`match 35-mm-film fidelity
`
`By JOHN FREE
`
`WASHINGTON. DC.
`
`For several days, groups of govern-
`ment officials, politicians, and jour-
`nalists crowded into a darkened room
`at CBS's offices here. We‘d come to
`View a rare. one-time collection ofvid-
`e0 gear. "What we are going to show
`you," CBS‘s Joseph Flaherty, vice-
`president of engineering develop-
`ment, told my group. "is a combina-
`tion of high-resolution TV,
`stereo
`sound, wide-screen TV, and enhanced-
`color TV."
`During the next hour I watched a
`variety of amazing TV images that
`had extraordinary clarityimore than
`five times the detail of television pic—
`tures you see on conventional home
`receivers. The high—resolution pic—
`tures, a dazzling match for sharp-
`focus 35-mm slides, were shown on
`special "Cinerama-type" direct-view
`sets and a large-screen projection TV.
`Other equipment used by CBS, such
`as microelectronic encoding circuits
`and a Sony-built digital video record-
`er, may have a key role—in improved
`forms—in delivering this new type of
`TV to you during the 1980’s.
`Actually, so-called high—definition
`TV (HDTV) has been available for
`closed-circuit use in medical schools
`and business applications for a few
`years. But it has been limited to live
`transmissions using only cameras and
`TV monitors, Recently, professional
`Yldeotape machines capable of record-
`mg HDTV were unveiled. As a result,
`HOllywood directors may soon put
`10.
`'0'
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`high-resolution TV to work in produc-
`ing movies, and broadcast networks
`will use it to enhance the quality of
`standard programing.
`CBS has still another reason for pro—
`rooting HDTV. It and other broadcast»
`ers require transmission channels to
`get these super-fidelity pictures into
`your home. For reasons detailed be-
`low, high-resolution TV can’t be car-
`ried easily on regular TV channelsi
`and no one plans to disrupt today's
`standard TV programing based on the
`525-line NTSC lNational Television
`Standards Committee) format.
`But HDTV can be transmitted into
`homes by direct-broadcast satellite.
`CBS is telling officials that it’s vital to
`reserve HDTV frequencies on a new
`class of satellites slated for launch
`within a few years.
`
`More pixels, better picture
`How does HDTV differ technically
`from standard TV? Standard NTSC
`sets, functioning perfectly, can dis-
`play 483 lnot 525) horizontal scan
`lines created as electron beams paint
`TV pictures by sweeping back and
`forth over picture-tube phosphors.
`Each horizontal scan line can resolve,
`or display, 436 separate picture ele-
`ments, called pixelsfian NTSC pic—
`ture can display 210,588 pixels,
`In practice, new sets equipped with
`so-called comb filters IPS, Aug.
`’78]
`show only about 330 horizontal ele-
`ments; most older sets average only
`about 250 picture elements per scan
`line. By contrast, although no firm
`standards have been set, a 1,125—line
`HDTV picture might contain not
`twice but some five times as many pix—
`els [one milliom compared with an
`ideal NTSC image. Each one of the
`high-resolution scanning lines carries
`more image detail, and each is longer
`
`because of the wide-screen picture for-
`mat. As a result, high—resolution TV
`requires more frequency space, or
`bandwidth typically, 30 MHz versus
`4.2 MHz for standard NTSC TV.
`"The NTSC system has given us
`Very good service during the last 25 to
`30 years," said Flaherty, "but we are
`pressing it to its maximum as pictures
`get larger and larger." A demonstra-
`tion made this very apparent. Two
`cameras were set up in an adjacent
`room overlooking a street. One was a
`state—ofthe-art CBS camera to dis-
`play standard 525-1ine TV pictures.
`The other was a 1,125-line model
`made for Japan’s public broadcasting
`corporation (NHK).
`The 525~line camera piped its pic-
`tures to a Kloss projection TV before
`us with a six-foot-diagonal screen (and
`to regular TV studio monitors). The
`NHK HDTV camera sent its pictures
`to a Matsushita-built wideformat
`projection TV and wide—format moni-
`tors (see color pictures).
`Pictures of a bowl of fruit were
`impressive on the 525-line Kloss and
`smaller monitors. But contrasted with
`the crystal-clear images on the HDTV
`sets, the limitations of NTSC pictures
`were dramatic. Training both cam-
`eras on the street below produced even
`sharper contrasts. I could read license
`plates and other vehicle lettering on
`HDTV sets that were a hopeless blur
`on 525-line receivers.
`Why do today's sets have a squarish
`picture ratio four units wide and three
`high? "It was chosen for very simple
`reasons,” said Flaherty. "First, it was
`all we could do Itechnologicallyl, and
`it was the way films were made," he
`said, describing the 1940’s mono-
`chrome—TV format.
`An HDTV system unveiled by Sony
`Continued
`
`
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`PMC Exhibit 2026
`Apple v. PMC
`IPR2016-00755
`Page 1
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`NOVEMBER 1931 l 10:
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`Projection TV displayed by Matsushita at technology exhibit in
`Chicago this summer uses red, green, and blue projection tubes
`like conventional models, but displays high-definition 1,125—line
`images from TV camera. Screen is 55 inches diagonally.
`
`“Tide-screen high-resolution monitor developed by NHK and
`Matsushita has 30-inch-diagonal screen, 5:3 aspect ratio. Phos-
`phor dots are much smaller than on conventional shadow-mask
`tubes, and NHK uses a digital beam-convergence system.
`
`PMC Exhibit 2026
`Apple v. PMC
`IPR2016-00755
`Page 2
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`last spring can show pictures in stan-
`dard 4:3 format, the extra-wide Cine-
`mascope format, or an intermediate
`picture width. The high-resolution
`sets at the CBS demonstration had a
`5:3 picture-aspect ratio. In addition to
`letting you see most or all of the pic-
`ture from wide-screen movies, sitting
`close to sharp, wide-screen HDTV
`images conveys more of the visual
`impact of a theater screen.
`
`Digital demonstration
`Warming up in another CBS office
`was a special type of videotape record-
`er completed by Sony just six weeks
`earlier. Bill Connolly, managing di-
`rector of development for the CBS-TV
`network. prefaced another impressive
`demonstration: "Engineers today are
`generally agreed that digital
`tech—
`niques are the proper way to record
`this HDTV information and transmit
`it," he said lPS, March '78].
`Connolly explained that with con-
`ventional TV, voltage is proportional
`to brightness. The brighter the scene
`at any given point on the screen, the
`higher the voltage. Since the voltage
`is analogous to what’s on the screen,
`it’s called an analog system.
`"The digital system does something
`quite different," Connolly said. The
`voltage generated by the camera is
`constantly sampled or measured by
`digital circuits. Each of these samples
`is then assigned a binary number (we
`rm; and ones) representing its inten—
`sity. This technique for each pixel on
`the scan lines requires considerably
`more bandwidth, or frequency spec-
`trum, for storage and transmission.
`While this large-bandwidth require-
`ment is a problem, major efforts are
`under way to shrink the frequency
`space needed for digital TV.
`"One of the things we can do is
`reduce the number of bits [binary dig-
`its] necessary to describe a picture,"
`Connolly said. He pointed to one of his
`“favorite symbols,” a CBS eye glowing
`on monitors. Running his finger
`across one scan line on the eye, he
`explained that it carried about 150
`black pixels, then 200 blue, and 150
`black ones again.
`"We waste a lot of [frequency] spec-
`trum with analog TV because we
`transmit every one of those things
`using the whole bandwidth,” Connolly
`said. With digital techniques, though.
`a single brief signal can be encoded
`that tells the digital circuits in the
`receiver to create 150 black pixels.
`This coding of the digital signal,
`requiring perhaps only a few dozen
`bits instead of hundreds of repetitive
`signals, cuts the rate at which hits
`must be transmitted—plus bandwidth
`requirements. Similar bit-rate-reduc-
`‘10
`POPULAR SCIENCE
`
`tion coding can produce the 200 blue
`and 150 black pixels for an “eye” scan
`line.
`John Rossi of the CBS Technology
`Center (Stamford, Conn.) demonstrat-
`ed a CBS 4:1 bit-rate-reduction sys-
`tem with an analog videotape ma-
`chine. An NTSC 525-1ine test pattern
`shown on monitors was created by a
`digitally coded signal that required
`only 28 megabits (million bits) per sec-
`ond instead of the 144 megabits/sec.
`from the original digital sampling.
`"This is a very simple bit-rate-
`reduction technique,” Rossi said. “The
`circuits can literally be held in the
`palm of your hand. This leads us to
`believe that with more-complex cir-
`cuits much higher bit-rate reductions
`can be achieved.”
`"Failing these bit-reduction
`schemes, HDTV will not be broadcast-
`able," added Flaherty. He hopes to fit
`digitally compressed high-resolution
`TV into a normal or nearly normal TV
`channel. "Much work has yet to be
`done," he said, "but you can see we’ve
`achieved a 4:1 reduction in bits fairly
`well, transmitting a roughly equal-
`quality picture.”
`That test-pattern picture I saw had
`some noise but carried the fine detail
`indicating most of the image was get-
`ting through. For this demonstration,
`a normal 4.2-MH2, 525-line NTSC sig-
`nal became a 114-megabit/sec. digital
`signal that was compressed into a 28-
`megabit/sec. signal. But that digital
`525-line signal would require about
`four VHF channels on your TV set. An
`HDTV signal, even before it’s digital—
`ly sampled, requires about five.
`
`Pouring marbles
`Why, ifdigital coding ofa TV signal
`takes up so much more frequency
`spectrum,
`isn‘t high-resolution TV
`more feasible with analog signals?
`High-frequency noise is one reason.
`Noise, which can spoil standard TV
`images, devastates HDTV.
`Connolly demonstrated another ad-
`vantage of digital TV by first showing
`a 525-line analog—signal picture of a
`fruit bowl from tape. Then he showed
`the same picture after it had been re-
`recorded 10 times—a tenth-generation
`copy. The image was smeared, full of
`noise, and color values were shifted.
`For broadcasting, about five genera—
`tions is the limit, he said.
`But scenes that followed from tenth-
`and even twentieth-generation digi-
`tally coded tapes seemed unaltered
`from the originals. Connolly com-
`pared analog taping to pouring
`water from one glass to others: Some
`water sticks to each glass; retaping,
`similarly. robs parts of the original
`signal with each generation.
`
`Digital signals, by contrast, are
`either the presence or absence 0f
`pulses on tape. They survive trans-
`mission and taping much better, and
`Connolly compared the digital tech-
`nique to pouring marbles from glass to
`glass. Themarbles (digital bits) get
`through unchanged.
`CBS engineers were impressed with
`Sony's new digital recorder. "In just
`seven years there’s been a 50:1
`improvement in the ability to jam bits
`into a small area of tape,” said Flaher-
`ty. "We went from under one million
`[bits] per square inch to 40 million.
`We only need a 3:1 improvement over
`that to record [digital] HDTV.”
`CBS also presented an NTSC video-
`tape made with stereo sound at a Ken-
`nedy Center concert. HDTV research-
`ers believe stereo is needed to bring
`the realism of wide—screen movies and
`other programs into your home. Dur-
`ing the demonstration of a Mozart
`operatic aria, repeated switching be—
`tween stereo and monophonic modes
`made stereo’s advantages obvious.
`HDTV offers superior color, too. A
`future international high-resolution-
`TV standard will no doubt provide viv-
`id hues that can‘t be obtained with
`NTSC color standards. Moreover,
`HDTV pictures can be transmitted
`with luminance (brightness) and color
`signals separated. Standard TV sig-
`nals have combined these—disastrous
`for picture fidelity—to achieve com-
`patibility between black-and-white
`and color receivers.
`You may first encounter HDTV not
`on a TV receiver but displayed on a
`theater movie screen. Sony might
`lease its prototype HDTV gear within
`a year for Hollywood production work
`that would be converted to film. Vid-
`eotaping offers advantages in econo-
`my and flexibility.
`In a different application, CBS
`plans to use HDTV in about three
`years to enhance standard broadcasts:
`HDTV tapes would permit special pro-
`duction techniques, such as image
`enhancement and zooming without
`picture degradation, before conver-
`sion to regular NTSC recordings.
`Also, cable TV and home videodiscs
`and tapes may bring HDTV to you in
`the 1980’s. You would need a special
`receiver or player, but such sources
`could bypass the standards and regu-
`latory problems of broadcast HDTV.
`"The real question is whether this is
`going to be available to the general
`public or whether it will be something
`only for the videophile with the money
`to buy all these ancillaries,” said Fla—
`herty. Getting wide-band HDTV into
`broadcast channels, he said, "depends
`,
`on the skill of the engineering commu-
`nity to make it fit.”
`'3 1.
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`PMC Exhibit 2026
`Apple v. PMC
`IPR2016-00755
`Page 3
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