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Introduction, Skew equalization, Versatools – Extron Electronics SEQ 100 15HD User Guide User Manual

Page 4: Seq 00 skew equalizer

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VersaTools

®

SEQ 100 Skew Equalizer

Chapter One • Introduction

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VersaTools

®

SEQ 00 Skew Equalizer

Introduction

The manufacturing process for network (CAT 5e) UTP cable

leads to a condition called pair skew. The Extron SEQ 100 15HD

Skew Equalizer corrects skew delay (misconvergence) problems

commonly encountered when using Category (CAT) 5, 5e, or 6

twisted pair (TP) cables for RGB video transmission. The

equalizer can also be used to correct for skew problems in

component video transmission systems. The SEQ 100 15HD

inputs and outputs video on 15-pin HD female connectors.

N

An SEQ 100 skew equalizer should not be necessary

when Extron Enhanced Skew-Free A/V UTP cable is

used.

Skew equalization

Skew exists between pairs when the physical length of one

wire pair is different from another. As the transmission cable

length increases, the amount of skew increases. Skew affects the

displayed image when the differential length between wire pairs

exceeds 2 feet, causing the timing of the red, green, and blue

video signals to appear out of alignment (horizontal registration

errors). The signals transmitted on the shortest pair are shifted

to the left if using white lines on a black background. A white

vertical line on a black field can appear as individual red, green,

and blue lines that are close together; the signal transmitted on

the shortest wire pair leads the other colors and appears to the

left on the display.
The skew equalizer provides three separate time delay circuits,

on the red, green, and blue video lines. Each time delay circuit

can be independently adjusted, from 0 to 39 nanoseconds, to

properly align the red, green, and blue video signals on the

displayed image.
The SEQ 100, installed in a TP transmission system and correctly

set, delays the video signal, red, green, or blue, on the shortest

wire pair to properly converge the displayed video image. The

skew equalizer can be connected between the TP transmitter

and its video source or between the TP SEQ and its connected

display device, whichever is more convenient. Figure 1 shows

the SEQ 100 installed on the SEQ output, which is the typical

configuration.

N

You should not connect the SEQ between the TP

transmitter and a source if you are also connecting a

local monitor.