AT4039EML
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User Manual
15
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clock and vice versa, you have to click apply for changes to take effect (this takes a few
seconds).
Mode & Clock Out Settings (Apply to all channels at once)
The “Ref” denotes the frequency of
the clock output. This is a function of
the bitrate and will vary according to
your clock-out settings under the
“Mode” menu. Knowing the clock
frequency being output by the BERT is
helpful when you want to trigger an
oscilloscope.
Some oscilloscopes require a clock
frequency above 2 GHz. To get the
AT4039EML to output that, go under
mode settings and select the Clock out
to be “Monitor”. Choose the
denominator so that the result is
within the scope range.
To switch between NRZ and PAM-4
coding, use the TX Mode setting, then
click Apply.
The options Gray Mapping and DFE
pre-coding are only available in PAM4
mode.
DFE Pre-coding sends a pre-amble for a
DFE receiver to sync to before the
actual PRBS pattern is transmitted, to
avoid DFE error propagation. The
decoder implements a 1+D scheme in
response to an
𝒙 =
𝟏
𝟏+𝐃
encoding.
Currently the DFE precoding is
automatic and not user-selectable.
Gray Mapping enables use of PRBSxxQ
defined in IEEE802.3bs. When Gray
