Teledyne LeCroy Eye Doctor II - Manual (Page 28)

Eye Doctor II Software
FFE Filter Algorithm
Feed-forward equalization is implemented as a tapped delay-line filter, with the 1 tap per unit interval.
The filter is mathematically described as follows:
Where:
n
y
in
(t) is the initial waveform
n
y
out
(t) is the transformed waveform
n
N is the number of taps
n
P is the number of precursor taps
n
k is the tap index, ranging from 0 to N
n
C
k
are the coefficients, or tap values
n
T is the time delay for each of the delay elements (nominally 1/bitrate)
Depending on whether you have chosen to include precursor taps, the FFE filter can introduce a delay in
your output waveform. The training algorithm seeks to find a solution for the tap values that retains the
edge position, but note that when manually creating tap values, the output waveform can be advanced
by adding precursor taps.
FFE block diagram.
26 922961 Rev A