\begin{table}%t4
%%\centering
\par
\caption{Control loop performance and optimum repetition frequencies (0~Hz means that no control
loop is used) as simulated on a 100~s  observation sequence, for the GENIE instrument working on
the 8-m Unit Telescopes (UT) at the VLTI (results taken from Paper~I) and the ALADDIN
instrument at Dome~C. The observations are carried out in the $L$~band for a Sun-like G2V star
located at 20~pc using either the 47-m UT2-UT3 baseline at the VLTI (waveband: 3.5--4.1~$\mu$m) or
a baseline length of 20~m for ALADDIN (waveband: 3.1--4.1~$\mu$m). The goal performance for
exozodiacal disc detection discussed in Paper~I appears in the last column. The total
null is the mean nulling ratio including both the geometric and instrumental leakage contributions.
The last line gives the standard deviation of the instrumental nulling ratio for this 100~s 
sequence (note that we give here the standard deviation of the mean instrumental nulling ratio
computed on the whole time sequence, which is more representative than the frame-to-frame deviation
presented in Paper~I). \label{tab:loopperf}}
\begin{tabular}[h]{cccccc}
\hline \hline              &\multicolumn{2}{c}{GENIE -- UT}&   \multicolumn{2}{c}{ALADDIN} &
\\                  &   Worst case  &   Best case   &   Worst case  &   Best case   &   Goal
\\ \hline Piston    & 17~nm @ 20~kHz&6.2~nm @ 13~kHz&  14~nm @ 3~kHz&  10~nm @ 2~kHz& $<$4~nm
\\ Inter-band disp. & 17~nm @ 200~Hz&4.4~nm @ 300~Hz& 7.0~nm @ 0~Hz & 7.0~nm @ 0~Hz & $<$4~nm
\\ Intra-band disp. &4.1~nm @ 200~Hz&1.0~nm @ 300~Hz& 7.4~nm @ 0~Hz & 7.4~nm @ 0~Hz & $<$4~nm
\\         Tip-tilt &11~mas @ 1~kHz &11~mas @ 1~kHz &  9~mas @ 1~kHz&  9~mas @ 1~kHz&(see intensity)
\\Intensity mismatch&   4\% @ 1~kHz &   4\% @ 1~kHz &  1.2\% @ 0~Hz &  1.2\% @ 0~Hz & $<$1\%
\\ \hline Total null&$9.7\tothe{-4}$&$6.2\tothe{-4}$&$2.9\tothe{-4}$&$2.2\tothe{-4}$& $f$(baseline)
\\Instrumental null &$5.0\tothe{-4}$&$1.5\tothe{-4}$&$2.0\tothe{-4}$&$1.3\tothe{-4}$& $10^{-5}$
\\         rms null &$4.5\tothe{-6}$&$2.0\tothe{-6}$&$5.0\tothe{-6}$&$3.5\tothe{-6}$& $10^{-5}$
\\ \hline
\end{tabular}
\end{table}