`
`PMC Exhibit 2020
`
`Apple v. PMC
`|PR2016-00753
`
`Page 1
`
`PMC Exhibit 2020
`Apple v. PMC
`IPR2016-00753
`Page 1
`
`

`

`I
`
`I
`
`I
`
`I
`
`-
`
`New equipment promis'
`super-fidelity in
`'
`sight and sound
`
`'
`BY JOHN FREE
`The digital electronics rayon}-
`that brought you the pocket “,7
`lator, digital wristwatch, 'I‘V .,_.
`and home computers is be .,._
`to influence the way audio ':
`fidenty signals are recorded, a _
`and played back, plus the te]e' ii
`
`pictures you watch.
`Nothing new, you say? “E3
`enhance oudio and video be“ We
`puterized and digitized TV’
`tuners [PS Nov.
`’77],
`turn
`tape decks, and other produ
`years. The digital circuits for 4;
`products are designed to mg;
`tuning, give you digital road I
`speed, channel, or frequency,
`provide smoother, more a
`mechanical performance.
`In
`case,
`the circuitry helps
`"H"?-
`the continuous analog signals
`for audio and video.
`have 2.}
`But
`now engineers
`veloped techniques to digitize
`analog audio and video
`themselves. And the improv
`in highdidelity sound is so »‘-'
`matic that
`few hi-fi
`systeutisE
`listening rooms are good enough
`take full advantage of digi
`_
`audio.
`the new devices “I”
`Some of
`this radical
`im
`bring about
`merit will be described sho .
`But first, what makes a digi‘Cont:
`
`in
`
`
`
`
`Audio~disc player from Sony lbfll 1'
`provides ultrahigh—fidelity sound.”
`laser beam reads digitally coded 51
`on reflective discs. Production Pl
`will be smaller than prototype
`
`Dual-function players and discs under
`development by Hitachi (above) can play
`either audio or video discs‘ Machine is
`first
`to use a tiny semiconductor laser,
`which simplifies construction,
`
`so i POPULAR SClENCE
`
`
`PMC Exhibit 2020
`
`Apple v. PMC
`|PR2016-00753
`
`Page 2
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`PMC Exhibit 2020
`Apple v. PMC
`IPR2016-00753
`Page 2
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`

`

`amplitude pulses. The order of
`these
`pulses
`ruin
`be
`arranged
`(coded)
`to represent any analog
`signal converted into a digital for-
`mat. But moat important, the cir-
`cuits used to convert digitized sig-
`nals back into analog form will only
`recognize properly coded pulses.
`Noise, such as tape hiss, is ignored
`and you don’t hear it.
`Moreover, digital signals are far
`less susceptible to distortion during
`transmission. And even it the sig-
`nal
`is distorted,
`if the digital de-
`coder can recognize the on-ofi pulse
`sequencos, it can still recreate an
`analog signal
`that’s audibly or
`visually identical to the original.
`
`
`
`fContr'nued]
`
`signal so much better than the con-
`tinuous analog electronic signals
`from discs, tape, and other sources?
`One iactm- is that analog signals
`constantly change
`in amplitude
`and frequency. Weak,
`low-level
`analog signals can be drowned out
`or
`distorted
`by
`noisy
`storage
`mediums
`(tape bias)
`or during
`transmission {snowy TV pictures).
`Both low- and high-level signals
`may have their amplitudes and fre-
`quency characteristics distorted by
`amplifiers.
`
`Coded signals
`Digital signals, however, are sim-
`ply a series of on-or-ofl, constant-
`
`
`
`fiocordinglolavback adapter tlofti {or
`Sony's or other video-cassette recorders
`puts digitized audio signais on the cas-
`
`that normally store
`setto-tape tracks
`video signals. Fidelity exceeds that of
`nondigital professional recorders.
`
`La.e..-
`
`._s
`
`
`
`
`
`Oplicai disc-player system made by Mitsubishi
`and others has a dynamic range exceeding 98 dB.
`Spiral tracks of pits on discs [magnified at right}
`are about 0.6 microns wide, have a protective
`plastic coating against dust and smears.
`
`a: | POPULAR SCIENCE
`
`
`
`..«-.,
`The idea behind this ‘
`advance isn’t new.
`In in
`principle behind the digital
`nique often used, called p
`'.
`modulation (PCM), was pa -
`by British engineer Alec R
`.
`1939.
`Engineers
`have
`digital concepts for years to
`tary, space, and commercial)
`munications. But only now,
`low-cost microcircuits readily"
`able [P8, Jan}, have the ,_
`concepts become feasible for .i':
`entertainment products.
`The new techniques han' .4-
`and pops from discs, totally
`nate background hiss from
`and discs, reduce wow and flu
`unmeasurably low levels, and
`the dynamic range of mini
`difl'erence between soft and
`sounds—to levels approach
`of a concert hall.
`Changes in the pictures
`TV screen with digital tcc
`are more subtle, but the new
`ads are already making si
`changes in broadcast
`televi
`
`'
`
`Diital hardware
`Last year, an eye—opening
`of new devicesimost of th
`era] years from market
`in
`tion—were unveiled at audio I
`here and in Japan.
`The new digital hardware,. "
`the ways digital techniques
`"
`applied to TV broadcasting, 5 T "
`several categories:
`0 Audio discs and players
`digitally coded signals are
`development by several Ja
`firms. These machines work -
`like the Philips-MCA video
`[P8, Feb.
`'77] now scheduled
`introduction this year.
`I Tape recorders and Vi ' '
`sette-recorder
`(VCR)
`ads r
`with digital signal encoding 3”.-
`so abundant
`in prototype
`One VCR adapter (Sony's) 13
`ready being sold. The ada
`work with any of the VCR'S
`market [P8, Nov.
`'77] and "'
`owners to use their decks for __
`cording
`either
`ultrahigh-fid_ ‘
`audio or TV programs.
`0 Hi-fi power amplifiers
`‘
`special type of digital circ'lllt
`be made much smaller than "
`ventional
`amps. These 3 "
`Class-D or switching amplifiers-
`power
`super-efficiently instead
`wasting energy in the form or
`I Digital video circuits 81'“
`ready being used by brogdon
`
`'
`
`PMC Exhibit 2020
`
`Apple v. PMC
`|PR2016-00753
`
`Page 3
`
`PMC Exhibit 2020
`Apple v. PMC
`IPR2016-00753
`Page 3
`
`

`

`r"
`
`1.,
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`'-r.':'.
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`in the long chain of amp ‘
`switches that process si
`twaen camera and transmi
`0 Digital TV signals 13
`to your home like a conv
`VHF or UHF signal are
`I
`for
`reasons explained later,
`some day home TV receive 5.;
`pick up digital TV pictures
`to special roof-top antennas
`satellites
`[see
`“Satellite
`TV,” page 66}. Other horn
`receive extremely high-quali
`ital TV pictures through i.
`cable or hair-thin glass fibers-
`August ’75}.
`
`_
`
`SEE NORTH
`CAROLINA FOR1893
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`The Nortbfirolfm fiavet'PacAage befpsyauplanyour vacation befiveyoa
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`there, and wbmto stay And Etiyoarsfbrtbepfice ofc stamp
`Nomjart when crayon 11%er tofi'ada better vacation bargain than that?
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`Sim
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`
`
`The BIG BOSS by MAINSTREAM
`. . . the final word in men's footwear
`
`Leather padded comfort
`collar. Day-long
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`
`The patented non-slip,
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`Won't slip on wet wood,
`steel. concrete. you
`name it.
`
`
`
`a
`
`-_
`
`Analog limitations
`The availability of low-cos
`cuits is one reason engines
`looking at digital
`technolo
`home entertainment. But au'
`perts also want
`to mini
`'
`eliminate the many technical
`lems that plague conventional, is.
`and disc recordings.
`Most recordings start on :-
`siona] analog-type taps
`-
`which, despite their quality
`high prices, immediately limi
`dynamic range of a recording.
`high-frequency signals can
`saturate the magnetic psi-ti
`tape, causing distortion. A
`other extreme, faint music 5:
`often must be boosted in amp
`so they aren’t buried in the n 2;:
`frequency background hiss.
`Because of these tape limits
`recording engineers and home
`cordists as well must restrict;
`dynamic range of recordings, 1
`'
`much of the sonic impact and
`citernent of the live perfo in
`Musical peaks are electron!
`and manually limited (a knob)
`The problems are compo w
`when taped signals are transf"
`to plastic discs and mass prOd _
`Fragile disc surfaces scratch
`while dust and dirt attracted 1:0
`grooves are ground in by the SW '
`to cause permanent damage
`ther, the restricted dynamic
`from the tape may have to be - -
`pressed more. Record com
`must insure that during loud
`sages
`the
`groove-cutting
`5W
`doesn’t create grooves that
`'-
`distortion or throw your stylus .,
`of contact.
`I_
`Most audio discs, therefore, "'
`vey a feeble imitation of the .
`dB or so difl’erence between
`orchestra’s loudt and lowest—1
`passages. Good discs produced, a“...
`Cont 1'
`‘
`
`'
`
`I
`
`PMC Exhibit 2020
`
`Apple v. PMC
`|PR2016-00753
`
`Page 4
`
`PMC Exhibit 2020
`Apple v. PMC
`IPR2016-00753
`Page 4
`
`

`

`to 20 kHz; 3M's tentat-
`specifioations for
`the
`ance extend from 30
`(The 3M machine a
`20Hzto 20kszitl-m
`deviation. )
`
`;
`
`’
`
`Dual-mode player
`The prototype disc :1
`Sony, Hitachi-Nippon
`and Mitsubishi—Teac-T'
`use an optical recordm
`back system. Disca
`.
`corded at the factory.
`the firms cooperating
`working on a two-mode
`that
`can
`produce
`as
`images or ultra-high-fi
`With these audio .
`the POM-encoded an ‘.
`spiral track of pits or I
`disc
`surface. The
`video discs have simi
`the signals are not
`before
`conversion '
`track. As the audio
`1800 rpm, a laser
`from the track is d
`stereo signal. To pm:
`from dropouts, about a
`the digital PCM p
`dundant. The DIA -
`cuits can sense when 33
`occurred and use a dull
`Although PCM an
`era aren't available 1' =
`is
`selling
`
`a
`
`
`
`vice converts a VCR
`high-fidelity audio is
`The adapter
`i see
`about
`twice as much -
`deck.
`Matsushita and Mi
`also shown VCR _a
`Sony’s,
`these plug-1n
`vert conventional analo _-
`nals into a PCM
`then into a video-type
`the VCR can proceBB-
`coding process is re -
`playback and the .o
`adapter is plugged Into
`tern like any other time
`Sony is also refinln8__
`kind of digital technol
`volves amplifying and!
`drive loudspeakers.
`market
`a
`so-called
`pulse-width-modulauon
`hi-fi power amplifier.
`'
`totype model I saw '
`watts per channel.
`'
`only 22 pounds and
`
`-
`
`PMC Exhibit 2020
`
`Apple v. PMC
`|PR2016-00753
`
`Page 5
`
`Digital hl-fi and TV
`[Continued]
`
`
`
`
`
`the conventional
`Digital encoding of
`analog signals for TV pictures requires
`enough pulses in the digital words rep-
`resenting amplitude levels to recreate
`
`the image. A three—bit-long digital word.
`left. clearly reduces detail in flat areas.
`An eight-bit word. right, provides an ex-
`cellent TV picture.
`
`a master tape may achieve a 65-dB
`dynamic
`range.
`(For
`reference.
`each six—dB increase in sound is
`perceived as being twice as loud.)
`The British Broadcasting Corp,
`obliged to provide quality stereo
`FM throughout Great Britain, was
`among the first
`to apply digital-
`signal encoding to home entertain-
`ment.
`
`Digitized FM
`During the late 1960’s and early
`1970’s,
`the BBC devised a meth-
`od of transmitting digitized stereo
`FM over the telephone lines and
`microwave links connecting studios
`and transmitters throughout Great
`Britain.
`'
`from,
`An analog output signal
`say, a BBC master tape is sampled
`thousands of
`times each second.
`Each sample, which represents the
`amplitude of the analog waveform
`at an instant in time, is coded into
`a series of on-off pulses called a
`digital code word (see box, p. 60).
`As
`the tape plays, a stream of
`digital words
`representing
`the
`music can be sent over phone lines
`or microwave hundreds of miles to
`various BBC studios.
`the digitized
`What happens if
`signal is distorted along the trans-
`mission path? Signal distortions
`that might garble an FM analog
`signal have virtually no elfect on
`a digital signal. The digital-to-ana-
`log (DIA) converter at each BBC
`studio need only recognize how the
`' on-ofi pulses in each word are or-
`ganized to recreate the exact ana-
`log signal amplitude. Digital words
`must almost be knocked out of the
`data stream before the DfA con-
`verter fails to do its job. Moreover,
`duplicate code words can be sent
`so that
`losing some words may
`have no effect at all.
`
`as [ POPULAR SCIENCE
`
`After the BBC upgraded the re-
`liability and quality of
`its FM
`transmission links, it next wanted a
`practical
`tape machine to record
`and play signals
`in a digitized
`form. In 1975,
`the BBC and 3M
`Company began a joint develop-
`ment project on a commercial digi-
`tal recorder. Late last year I saw
`3M’s new $150,000 digital reCOrder
`at a press conference.
`A demonstration tape on the pro-
`fessional machine had an awesome
`clarity and dynamic range. But the
`demonstration roomsas with most
`home environments—was too noisy
`for us to fully appreciate the re-
`corder’s 90-dB dynamic range. The
`machine can record 32 separate
`tracks—each for separate perform-
`ers, if desired—on special one-inch-
`wide tape.
`With the techniques the BBC-
`and 3M devised to encode audio
`signals, specifications such as wow
`and flutter, distortion,
`crosstalk
`(interference between tracks), and
`print-through
`have
`become
`in~
`audible or exceptionally low.
`But
`the exciting news
`in the
`audio field is the large number of
`digital tape and disc machines be-
`ing developed in Japan for home
`use. With these new machines, the
`superb fidelity captured by 3M’s
`professional recorder can be trans-
`ferred to mass-produ0ed discs and
`tapes with absolutely no loss in
`sonic quality.
`Most of the new digital machines
`are in the prototype stage and may
`not be available for a few years. At
`least nine Japanese firms have un-
`veiled digital audio gear.
`In some respects, a few of the
`products designed for home use are
`superior to 3M’s costly professional
`tape machine. Sony's PCM disc
`player, for“ example, has a flat fre-
`
`PMC Exhibit 2020
`Apple v. PMC
`IPR2016-00753
`Page 5
`
`

`

`
`
`
`
`w l:
`'
`
`for home entertainment
`gradual. The steep initial
`playback hardware is likely
`tract only audio perfectio
`first. But the same industry ‘_
`ing curve" that enables
`turers to continually shri
`cost of mass-produced digi
`oulators
`and wristwatchesi‘
`eventually bring this drama :3»?
`vance in communications to : '
`
`ls usually sam
`levels. A signal
`at least twice its bandwidth from;
`4.5-MH2 TV signal may be camp
`million times each second. 8
`each sample requires an eight-b
`word. the transmission medium
`digitized signals might hava to
`least 88 million hits per seco
`more often 100 million hits Per
`That many hits each second
`a bandwidth capacity of about 5
`some 10 times greater than an
`signals.
`To reproduce the convention
`signal from the digital signal.
`words are used to recreate the
`sample levels: filters than “smo
`staircase-like steps from the w _.
`to duplicate the analog signal.
`Pulse-width modulation lthre
`diagrams at left}. used In Son
`hi-li power amplifier also involv
`pllng the input signal. But milk
`the samples are not coded. A
`
`
`
`are converted into triangular sha
`nals and mixed as signal and
`with the input analog signal from.-
`amp. This mixer stage sampls ill
`and the resulting signal is fed 1
`gain power uansistors..These trans 2.;
`switched abruptly on and all. pro
`serles oi pulses whose widths
`portlonal to the input signal am
`A filter circuit can then' transfor
`pulse-width signals back into a
`audio signal that's identical to
`tlonal power-amp outputs:
`
`PMC Exhibit 2020
`
`Apple v. PMC
`|PR2016-00753
`
`Page 6
`
`now'on the. market can convert. chili“
`ventional TV signals-into a digital
`format for similar enhancement.
`Also, equipment is available that
`digitally converts European TV sig-
`nals into US. broadcast standards
`or vice versa. Other hardware in-
`sures that signals sent from one
`studio to another are synchronized
`so pictures won’t roll when directors
`switch from one scene to another.
`Other digital equipment is expected
`to gradually replace analog video
`circuits and improve the quality of
`the picture on your TV screen.
`Broadcasting digitized TV sig-
`nals directly to your home could
`radically improve the pictures you
`see, virtually eliminating signal
`noise or “snow.” But
`that's not
`likely to happen for some time be-
`cause of the enormons bandwidth
`(range of frequencies) required for
`a PCM television signal (ace box).
`
`Narrowing the bend
`Researchers at CBS Technology
`Center
`in Stamford, 001111., and
`elsewhere are studying ways to
`
`Mimic
`
`fl“ “"5
`
`
`
`Jy domino: compared tb conven-
`ual amps with similar power.
`_ The reason for the compactness
`
`l'is'that PWM amplifiers (see box)
`operate continuously at efficiencies
` ,q
`of 90 percent or better, converting
`input
`(AC) power primarily into
`.' output power
`for your speakem.
`conventional
`hi—fi
`power
`*‘l-ainplifiers reach a maximum elli-
`_-ciency of about 75 percent only
`when they’re supplying maximum
`output Power (musical peaks). 0r-
`amps have an average elli-
`_-ciency of about 20 percent, with
`Imost of the input power wasted as
`gloat. Bulky metal heat sinks are
`needed to diesipate this heat.
`
`
`
`_ it..
`
`..
`
`.. ‘
`'L.‘
`.r
`I'
`
`"
`{
`
`I
`
`fr_
`
`' Digital television
`,
`'
`tech-
`PCM and other digital
`
`._._ :niques are already being used in
`'
`'.commercialtelevisiontomanipulate
`TV signals between cameras and
`transmitters. Digital
`techniques
`-.were need to send pictures back
`I irom Mars, and computer process-
`ing of
`these signals can remove
`noise and enhance images. Devices
`
`plenum storm.
`
`i
`
`momma
`
`l.-l
`
`r.'- \_ c
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`'
`
`l
`
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`t.I
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`. C
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`
`How analog signals are converted into digital form
`An analog signal changes value or ampli-
`- Pines-trio: uncommon
`tude with time: the familiar sine wave is
`SAMPLES
`a good example. The voltage represented
`OFSIGNN.
`rises smoothly to a peak in a positive di-
`rection. reverses and falls and eventually
`reaches its maximum value in a negative
`direction. then returns to zero. it passes
`through many Intermediate values in be
`tween. A digital signal. on the other
`hand, has only two states: either on or
`off. The signals are formed from the
`binary digits (called bits) one and zero.
`For conversion to digital form. the ana-
`log
`signal
`is
`sampled
`periodically.
`Viewed on an oscilloscope. the wave—
`form ItOp. left) could represent a brief
`instant of your voice over a telephone.
`er the more rapid change at a high-ire—
`quency violin note from a record. or the
`still more rapidly changing part of a TV
`signal that helps create someons's eye
`color on the screen.
`A voice signal might be 4000 Hz, the
`violin note 12,000 Hz. and the eye-color
`TV signal 3.5 MHz. For pulse-code mod—
`ulation lPCM) encoding. each sampled
`amplitude level on the waveform is held
`or memorized for an Instant.
`Next. each sampled level in the wave
`form ls assigned a digital code. The
`code is loaned lrom the binary digits
`zero and one. and a code ward In the
`digital PCM signal representing a given
`sample might be made up of eight hits.
`such as 11100011.
`The ones and zeros in an eight-bit
`code word can be arranged 256 different
`ways l2”! to represent 250 amplitude
`
`’
`
`\
`
`AND CARRIER
`
`.
`
`PULSE-WIN“ SIGNAL
`
`
`
`
`
`
`
`
`
`tandem.
`,
`*
`_
`ments for digital TV. But '
`home,_methods oi transmittin _-
`
`tal TV that can handle much l
`bandwidths, Such as coaxial 3-:
`;-..
`fiber optics, may be necessary
`Communication satellites,
`‘
`have already been used to
`digitized TV signals, operate
`tremer high carrier fr 0
`(thousands of megahertz). w
`ital TV signal,
`therefore,
`.
`a much smaller slice of the:
`width available. Satellites
`day be used to send digi
`signals to special TV ante
`
`PMC Exhibit 2020
`Apple v. PMC
`IPR2016-00753
`Page 6
`
`