24
5-
DFE: The Decision Feedback Equalizer (nonlinear adaptive equalizer) is based on the
principle that once the decision circuit has determined the value of the current
transmitted symbol, one can precisely remove the ISI contribution of that symbol to
future received symbols. Optimal DFE parameters can be determined by the GUI, and
it can also adaptively detect minimum taps required for a target Eye Height or SNR
value.
6-
FFE: With the Feed Forward Equalizer (linear equalizer), each value of the output
sequence is a weighted sum of the most recent input values. Optimal FFE parameters
can be determined by the software, and it can also adaptively detect minimum taps
required for a target Eye Height or SNR value.
7-
SIRC: Also referred to as SRC, stands for System Impulse Response Correction. It is the
extracted time domain impulse response of a reference O/E which is converted into
the frequency domain using an FFT. Two methods with which this file is generated are
discussed in detail in Appendix IV. Either method will yield a 4
th
Order Bessel-
Thompson roll-off as dictated by the IEEE 802.3bs/cd publication standards for both
NRZ and PAM4 optical signals.
