Sansui PC X11 Brochure

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The PC-Xll turns yourVCR Into
a digital audio recorder

To make digital recordings, all you need is
your VCR and a PCM digital audio processor
like the PC-X11

if you own a VCR. you can be ready to make digital
audio recordings by just connecting a PCM digital
audio processor. such as Sansuis high-performance
PC-Xf 1. The processor hooks up between your
present hi-fi system and your VCR-standard

video functions of your VCR are not affected in

any way.

Simple operation plus long recording time

of open-reel

Because digital recordings are made on your VCR
using standard videocassette tapes. operation is easy;
indeed, its just as easy as using a cassette deck-
just pop a cassette into your VCR and adjust recording
levels with the digital processor.

Recording time is much longer than cassette
tapes-you can record up to 160 minutes (2 hours.
40 minutes) of music on a VHS VCR (recording times
for Beta and other formats will be different). A profes-
sional-quality open-reel deck using huge 10-inch reels
may be able to make recordings with playing time
this long. but the fidelity of digital recording is far. far
superior. And. minute for minute. digital recording on
video tape is no more expensive.

With the PC-Xf i . you can record a WagnerorVerdi
opera. a Mahler symphony. or half a dozen of your
favorite albums on a single videocassette tape, and
enjoy superior digital sound from one end of the tape
to the other.

| PCM digital recording-how its done

PCM digital recording is very different from analog
recording. which we are all familiar with. Under EIAJ
standards applicable to digital audio recording using
videocassette tapes. the sampling rate is 44.056Hz and
quantization is 14 bits. This means music is sampled at
a frequency of 44,056Hz, and each sampled unit is
assigned a value among 214 or 16,384 possibilities.
After a musical signal undergoes sampling and quanti-
zation. its codified in the binary system using the digits 1
(presence of a pulse) and 0 (absence of a pulse). After
this. additional data for error detection and correction
are added. Then the digital signal containing both
music and this additional data is recorded onto the
videocassette tape.

Since in PCM digital audio the process of recording
(encoding) and play-
back (decoding) is
reduced to a simple
differentiation be-
tween 1s and 0s.
waveform distortion
(noise, distortion.
wow and flutter. etc).
common to analog
recording. is no
longer of concern.
Therefore. even after
many generations of

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PCM digital recording process

Sampling

Analog signal

Input level

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is unique to digital
recording.

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The Sansui PC-X_ll PCM
Processor.- De5lgned

for convenience .-
and super
hl-fl sound

it3 Sansui TRICODE PCM technology for
- If at superior data reading accuracy

The accuracy with which a PCM digital processor reads
digital data from a videocassette tape during playback
determines ultimate sound quality. because any inac-
curacy in data reading results in altered sound. Sansui's
TRICODE PCM technology affords our PC-X11 a data
reading capability about 100 times better than that of
most other PCM processors, This is why you can enjoy
such good recording results. And this same high accuracy
is available to you no
matter what video format
you use-VHS. Beta.
Philips 2000 or U-Matic.

~. With the PC-X11. its easy to record
~ . an and play

Maybe you think usmg a PCM processor must be
difficult; on the contrary. it's extremely simple to use,
0 Digital dubbing-You can connect two VCRs to the
PC-Xtt and undertake
digital dubbing between
the two. Even if you're
copying the copy of a
copy of a copy. there
will be no degradation
in quality whatsoever.
For connecting conver-
lence. the set of termi-
hats for the second
VCFi is up front.

0 Oversized fluorescent meters with peak hold -
Thirteen fluorescent dots per channel show peak levels
over a wide 75dB range Level settings are easy. For one.
levels are color coded - white from -60dB to OdB. yellow

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up to +15dB
and red for OVER
LEVEL. For another,
the +15dB reading is referenced
to the typical saturation level of
cassette decks.

0 Automatic TV/processor switching -The
PC-X11 is automatically bypassed when its off.
savmg you the trouble of reconnecting cables each

time you use the processor.

0 Headphone jack with level control- Because the
headphone output has its own level control.

you can monitor recording and playback at any level
you like

0 Connections for 2 monitor TVs-To help you integrate
your audio and video systems. the PC-X11 connects two
monitor TVs.

5 I, i

1.... "I Top-flight crrcurt de3igns and top-
- . as quality parts mean top performance

You cant expect to enjoy the full advantages of digital
recording unless your processor uses the most advanced
analog and digital Circuit deSigns and top-quality pans.
Thats why we use choice parts and circuits in the PC-X11.

Its rugged power supply features a highly capable,
low~hum torOidal power transformer. outsized capacitors.
largecapacity regulators. and other quality parts. Each
of the analog. digital and display circuits has its own
winding on the power transformer to prevent hum and
other mutual interference

Analog circuitry also enjoys the best of Sansui
technology. For instance. the input/output line amp and
AD/DA (Analog-toDigital/Digitalsto-Analog) converter
are DC configured. And we use rugged two-sided glass-
epoxy circuit boards. high-quality electrolytic capacitors.
first-grade reelstors. copper-film styrene capacitors. and
a copperplated chassis, All help contribute to the pure,
clean sound of the PC-Xt 1.

Degradation of data in
amplitude and time domains
During PCM digital recording. a slight
degradation of digital data is inevitable
due to limitations of the tape (in terms of the
frequency response and stgnal-to-ncise
ratio]. tape jitter and variations in amplitude.
When one analyzes the recorded waveforms of
digital data. one can see there are two types of
damage. One type occurs when the frequency
response of a VCR is so poor that the amplitude of
the data is not sufficiently high to permit the PCM
decoder to accurately assign a 0 or 1 value to each bit (Fig. 1a).

The other type occurs when jitter and mutual interference between
adjacent pulses shift the data forward or back in time [Fig 23). Less
than perfect data leads to readout error Sansui TRICODE PCM tech-
nology was specrfically developed to effectively reduce both forms

of data degradation.

Sansui TRICODE PCM technology: superior data
readout ability without waveshaping

At present there are two techniques lor reading impedect data One
involves "waveshaping." which attempts to improve the shape of the
data wavelorm being read. The other lS called "pulse detection" which
reads the data to determine Cs and is without manipulating waveforms.
The Sansur PCM TRlCODE techno cgy belongs to the latter category.
yet its radically different from other pulse detection decoders in that

it copes wtth damaged data in both ampitude and trne domains.

0 Reading data damaged In the amplitude domain

Units of data are aSSIgned the values 0 {low level] and 1 (high level]

by comparison wrth a reference level (slice level) Conventional PCM
processors use one lixed slice level therefore. in the example (Fig 1b).
though data units 2. 3 and 4 are read accurately. unit 1 is erroneously
read as 0. The Sansui TRICODE PCM processor employs two Slice
levels (th to] It detects the level at the center of each data wave-
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Sansui TRICODE PCM technology-

the most accurate
error correction system to date

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form. and. by comparing preceding data. automatically chooses the
optimum slice level for each unit of data, Assrgning values 0 and 1
is accomplished with far more accuracy.

0 Reading data damaged in the time domain

Since conventional PCM processors read data at the center of each
bit." they are prone to error when phase delay occurs (Fig. 2a] With
the TRICODE PCM processor. however. data is read at three pomts-
at the center of the bit. plus at points fonivard and back of it-and
assgned the value 0 or 1 Current data ts compared wrth preceding
data' if the measurements at three points in the first unit matcn those
in the second. then the current data is deemed to be the same as the
previous one (0 for 0, or 1 for 1) it not, the current data is given a
dlfierent value (1 for 0 or 0 for t] This has resulted in dramatically
improved tracking of phase variations in data waveforms. To date.
TRICODE PCM IS the only technology that accurately reads data
even when theres a shift in time.

Thanks to an improved reading ability of data damaged in the
amplitude and time domains. the Sansut TRlCODE PCM technology
makes it possible to read data. no matter how damaged it may be.
with uniaillng accuracy even when the recordings have been made
on pocrvguality VCR tapes.

TRICODE PCM processor works completely
automatically

With the Sanaui PC-X11 TRICODE PCM processor, the slice level

is automatically adjusted. as are time shifts. There's no need to adjust
controls each time
you use a different
tape or record on
a different VCR.
_ Remember that

' With other PCM
processors. manual
adjustments are

~ mandatory.

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