EXFO FTB/IQS-85100G Packet Blazer for FTB-500/IQS-600 - Manual (Page 272)

Test Functions
262 FTB/IQS-85100G
40/100G Advanced - Pre-Emphasis
TX

VOD (mv) allows to change the channel’s signal amplitude. The
default setting is 800 mV.

Pre-Emphasis Pre-tap 0t, Post-tap 1t, Post-tap 2t, which essentially
pre-distorts or modifies the energy/frequency content of signal
transitions, compensates for signal degradation by effectively reducing
reflections and crosstalk, while improving inter-symbol interference
(ISI). It is key to apply a known level of energy or pre-distortion on the
transition or bits, to help minimize high-frequency effects and allow the
signal to reach its destination at the receiver with improved detection
ability.
Pre-emphasis can be set with multiple taps—a tap being the coefficient
that will be added to the corrected bit. A one-, two- or three-tap
selection can be used to determine the right amplitude to be applied to
the corrected bit. A similar analysis can be conducted for post- or
de-emphasis where the correction will be applied to the post-bits.
The default setting is 0.
RX
Equalizer Control and Equalizer Gain (dB) allow to enhance the
receiver’s detection capabilities. This process offsets the
high-frequency effects of the transmission path by applying the reverse
transfer function of the frequency-energy content of the signal
compromised by the transmission path. Non-linear amplification of the
degraded frequency components in the signal is applied in an amount
that is inversely proportional to the loss or distortion in which the
components were affected by the signal transmission medium.
The default setting is 0.