\begin{table}%t1
\caption{\label{Tab1}Characteristics of the digital receiver.} 
%\centering
\par
\begin{tabular}{c c}
\hline\hline
\noalign{\smallskip}
Input-output channels & 2 \\
%\hline
ADC resolution, bits & 16 \\
%\hline
ADC sampling frequency,~MHz \\
(external/internal) & 10 ... 130 \\
%\hline
Input bandwidth,~MHz & 1 ... 65 \\
%\hline
Input impedance, $\Omega$ & 50 \\
%\hline
Input signal amplitude (max), V & $\pm$1 \\
%\hline
SNR, dBFS & 74 \\
%\hline
SFDR, dBc & $>$112 \\
%\hline
Noise floor, dBFS & --117 \\
%\hline
Effective number of bits (ENOB) & 12 \\
%\hline
FFT window length / resolution bits & 16~384 / 30 \\
%\hline
Time window shape & User-defined \\
 & (default = Hanning) \\
%\hline
Max. number of output frequency channels & 8192 \\
 & (i.e., 32~MHz total band with 4 kHz resolution) \\
%\hline
FFT window overlap & 0\%, 50\% \\
%\hline
Integration time & 0.25 ... 128 ms \\
(time steps, $N_{\rm a}$) & (2 ... 1024) \\
%\hline
Accumulated values precision, bits & 54 \\
%\hline
Output precision, bits & 30 \\
%\hline
Complex FFT calculation time, $\mu $s & 114 \\
%\hline
 & -- Waveform \\
Output modes & -- Power spectrum \\
 & -- Coherence \\
 &(Cross-correlation spectrum) \\
%\hline
Digital frequency down conversion & Optional \\
\hline
\end{tabular}
\vspace*{2mm}
\end{table}