9. Technologies
HDMI20-OPTC series – User's Manual
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9.3. Pixel Accurate Reclocking
Signal reclocking is an essential important procedure in digital signal
transmission. After passing the reclocking circuit, the signal becomes
stable, jitter-free, and can be transmitted over more equipment like
processors, or event controllers. Without reclocking, sparkles, noise,
and jaggies appear on the image.
Lightware’s sophisticated Pixel Accurate Reclocking technology
fixes more problems than general TMDS reclocking. It removes not
only intra-pair skew but inter-pair skew as well. The Pixel Accurate
Reclocking circuit eliminates the following errors:
Intra-pair skew
Skew between the + and - wires within a differential wire pair (e.g.
Data2- and Data2+). It’s caused by different wire lengths or slightly
different wire construction (impedance mismatch) in DVI cable. It
results in jitter.
Intra-pair skew
+
-
Inter-pair skew
Skew between two differential wire pairs in a cable. It is caused by
different wire pair lengths or different number of twists in the DVI
cable. Too much inter-pair skew results color shift in the picture or
sync loss.
+
-
Inter-pair skew
+
-
Jitter
Signal instability in the time domain. The time difference between two
signal transitions should be a fixed value, but noise and other effects
cause variations.
Jitter
+
-
Noise
Electromagnetic interference between other electronic devices such
as mobile phones, motors, etc. and the DVI cable are coupled onto the
signal. Too much noise results in increased jitter.
Noise
+
-
