Emphasis, Emphasis overview – Teledyne LeCroy Eye Doctor II User Manual
Page 11
Operator's Manual
Emphasis
Emphasis Overview
Emphasis is added to a signal as a way to pre-compensate for expected channel losses. Since high
frequency components are attenuated more by serial data fixtures and channels (making the high
frequency components higher amplitude than the low frequency components at the far end of the serial
data channel) they can be the same amplitude.
Emphasis Dialog
Touch the Emphasis button on the Eye Doctor II dialog to access the Emphasis dialog.
User interface for adding or removing pre-emphasis or de-emphasis
The Emphasis dialog allows you to:
l
Add Pre-emphasis - This implements a 2-tap FFE filter that boosts the amplitude of transitional
bits in your input signal by the amount Gain specified. See
for more infor-
mation.
l
Add De-emphasis - This implements a 2-tap FFE filter that attenuates the amplitude of transitional
bits in your input signal by the amount Gain specified. See
for more infor-
mation.
l
Remove Pre-emphasis - This implements an 8-tap FFE filter that attenuates the amplitude of tran-
sitional bits in your input signal by the Gain amount specified. See
for
more information.
l
Remove De-emphasis - - This implements an 8-tap FFE filter that boosts the amplitude of tran-
sitional bits in your input signal by the Gain amount specified. See
for
more information.
l
Add Custom emphasis - Specify up to 8 tap values for a custom filter response. See
for more information.
Checking or unchecking the Enable checkbox allows you to quickly enable or disable the Emphasis block.
Make sure to have the Nominal Bitrate set to the correct value in the Signal tab (SDAIII users) or in the
EyeDoctor II tab when configuring via Analysis --> EyeDoctor II (SDAII users).
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