Kramer Electronics VP-200xl User Manual

Kramer Electronics, Ltd.

USER MANUAL

1:2 VGA/XGA Distributor

Model:

VP-200xl

IMPORTANT

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: Before proceeding, please read paragraph entitled

"Unpacking and Contents"

Table Of Contents

Section Name Page

1 INTRODUCTION 2

1.1 A Word on VGA/XGA/Audio Switchers 2

1.2 Handling Graphics Signals 2

1.3 Factors Affecting Quality of Results 4
2 HOW DO I GET STARTED 5
3 UNPACKING AND CONTENTS 5

3.1 Optional Accessories 5
4 VGA/XGA DISTRIBUTOR 6

4.1 Getting to know your VP-200xl Distributor 6
5 INSTALLATION 8

5.1 Rack Mounting 8
6 CONNECTING TO VGA/XGA DEVICES 8

6.1 TYPICAL APPLICATION 8

6.2 HANDLING SIGNAL LOSSES 9

6.3 Adding more outputs 10

6.4 Adding more inputs 10
7 SPECIFICATIONS 10
8 TROUBLESHOOTING 11

8.1 Power and Indicators 11

8.2 VGA/XGA Signal 11
Limited Warranty

Figure Description Page

1 VP-200xl Front/Rear Panel Features 7
2 A typical application of the VP-200xl 8

Table Description Page

1 VP-200xl Front/Rear Panel Features 7

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List Of Illustrations

List Of Tables

1 INTRODUCTION

Congratulations on your purc hase of this Kramer VGA distributor. Since 1981,
Kramer has been dedicated to the development and manufacture of high quality
video/audio equipment. The Kramer line has become an integral part of many of
the best production and presentation facilities around the world. In recent years,
Kramer has redesigned and upgraded most of the line, making the best even
better. Kramer’s line of professional video/audio electronics is one of the most
versatile and complete available, and is a true leader in terms of quality,
workmanship, price/performance ratio and innovation. In ad dition to the Kramer
line of high quality VGA distributor, such as the one you have just purchased,
Kramer also offers a full line of high quality switchers, processors, interfaces,
controllers and computer-related products. This manual includes configuration,
operation and option information for the VP-200xl from the Kramer VP Tools
line, of VGA Distributors.

1.1 A Word on VGA/XGA Distribution Amplifiers

VGA/XGA Distribution Amplifiers distribute one or more signals to several
users. They vary in the number of inputs, looping capability, programming
capability, number of outputs, operating format, bandwidth and input/output
coupling. VGA/XGA Distributio n Amplifiers are used to distribute o ne source to
several acceptors (wide screen projectors, format converters etc.) for
simultaneous recording or monitoring of one source, with no discernible signal
degradation. The machines excel in very large bandwidth (some approaching
400Mhz) and very good linearity, making them usable for even the highest
graphics standards. A good quality distribution amplifier amplifies the incoming
signal, may pre-compensate the signal for potential losses (resulting from the use
of long cables, noisy source, etc.) and generates several identical buffered and
amplified outputs. The front panels of these Kramer Amplifiers are designed to be
simple to operate. Typical applications of the machines are: computer graphics
distribution in cla sses, poi nt of sale and multimed ia studios, d isplaying co mputer
graphics before large audiences using the data input of a wide screen video
projector.

1.2 Handling Graphics Signals

A computer generated graphics signal usually comprises 5 signals: Red, Green,
Blue - which are analog level signals, and two TTL (logic) level signals ­Horizontal Sync and Vertical Sync. (Digital graphics cards and monitors use a
different signal format, and will not be discussed here.)
Computer graphics resolution is measured in pixels and signal bandwidth. The
more pixels (picture elements) on the scree n, the more detailed the i mage. VGA,
S-VGA, XGA, S-XGA and U-XGA are terms describin g graphics resolution and

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color depth. Color depth represents the maximum number of simultaneously
displayed colors on the screen and is measured in bits. 24 and 32-36 bits of color
depth represent millions to billions of color shades available on the screen at any
given moment. (It should be born in mind, though, that the human eye can resolve
only a few thousands colors!) The more detailed the image (higher resolution)
and the higher the color depth the more real the image will look. The highest
resolution of standard VGA was 640x480 pixels with 4 bits of color (16 colors).
The standard VGA was able to use more colors (256) but at a lower resolution,
around 320x200 pixels, which was very crude. Common resolutions used
nowadays for computer graphics vary from 1024x768 up to 2000x1600 pixels
with “high color” - 16 bits of color, representing 64,000 different colors, up to
“true color” - 24 bits or more, re presenting fro m 16.7 millio n colors up to several
billion. Displaying such a detailed and colorful image on the screen needs
enormous graphics memory per frame, as well as very high speeds for “writing”
so many pixels on the screen in real time. The amplifiers that carry those signals
must be able to handle those speeds and signal bandwidth.
Standard VGA, at 640x480 resolution, needed amplifiers with 20-30MHz
bandwidth. At 1600x1200 or even at 1280x1024 (S-XGA), those amplifiers will
fail completely. In order to faithfully amplify and transmit modern high­resolution graphics, amplifiers with bandwidths of 300 MHz and more are
needed. Those amplifiers, besides the enormous bandwidth they handle, need to
be linear, to have very low distortion and be stable. Stability of an amplifier is its
ability to avoid bursting into uncontrolled oscillation, which is in adverse
relationship to the speed it can handle. The tendency to oscillate is further
enhanced by the load impedance. The load impedance of a system is usually not
just a resistor. A cable connected to an amplifier (leading to the receiver or
monitor) may present a capacitive and/or an inductive load to the ampli fier. This
is the main cause of instability. The quality problems of a load or cable may
severely degrade the bandwidth, linearity, and stability of the amplifier and in
general its ability to faithfully reproduce the signal.
Cables affect image resolution. Longer cables, due to imperfect characteristics,
cause high frequency deterioration and hence image “smear” and loss of
resolution. In computer graphics especially, this adverse effect is very much
accentuated. The amplifiers should therefore cope with an additional task ­compensating for cable losses up to the maximum useful operation distance.
High-resolution graphics systems should use very high quality cables for image
transmission. The cables should be shielded to eliminate externally induced
interference but the shield might itself increase the capacitance of the cable, and
therefore, cause deterioration in the image’s resolution and clarity. Standard
quality cables can only be a few meters long. For longer distances, compound

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cable is replaced by five individual coax cables, which are bulky and
cumbersome for use. Even then, the distance is limited to several tens of meters.
Cables may create other problems, which result from their failure to accurately
match the system’s required impedance. The result of this, especially at high
frequencies, is “shadows” or “ghosts” on the image, resulting from standing
waves and e lectronic reflectio ns runnin g back and forth bet ween trans mitter and
receiver. Another aspect to consider is the sync. As sync signals are logic signals,
which are not treated as analog signals, the receiver does not terminate the line,
and therefore the line is not matched. A host of problems can occur when sync
signals are sent over long, unterminated, unmatched cables. The result might be
image breakdown or distortion due to improper sync information. The amplifier
that drives the analog section of the graphics data should also be able to buffer,
recover and send the sync information in such a way that it is received properly at
the receiving end.

1.3 Factors Affecting Quality of Results

There are many factors affecting the quality of results when signals are
transmitted from a source to an acceptor:

⌦ Connection cables

- Low quality cables are susceptible to interference;
they degrade signal quality due to poor matching and cause elevated noise
levels. They should be of the best quality.

⌦ Sockets and connectors of the sources and acceptors

- So often
ignored, they should be of highest quality, since "Zero Ohm" connection
resistance is the target. Sockets and connectors must also match the
required impedance (75ohm in video). Cheap, low quality connectors tend
to rust, thus causing breaks in the signal path.

⌦ Amplifying circuitry

- Must provide quality performance when the

desired end result is high linearity, low distortion and low noise opera tion.

⌦ Distance between sources and acceptors

- Plays a major role in the final
result. For long distances of over 15 meters (~2 to 3 meters for
VGA/XGA) between sources and acceptors, special measures should be
taken in order to avoid cable losses. These include using higher quality
cables or adding line amplifiers.

⌦ Interference from neighboring electrical appliances

- They can have
an adverse effect on signal quality. Balanced audio lines are less prone to
interference, but unbalanced audio should be installed far from any mains
power cables, electric motors, transmitters, etc. even when the cables are
shielded.

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