\begin{tikzpicture}
\begin{axis}[
name=plot2a,
%at=(plot2.below south east), anchor=above north east,
xshift=1cm,
axis lines*=middle,
enlargelimits = upper, clip=true,
scale only axis,
axis line style={->,>=stealth},
xlabel={$\omega$},
ylabel={dB},
every axis x label/.style={
	at={(ticklabel* cs:1)},
	xshift=-0.2cm,
	anchor=north,
},
every axis y label/.style={
	at={(ticklabel* cs:1)},
	xshift=0.4cm,
	%yshift=0.35cm,
	anchor=south,
},
every outer x axis line/.append style={white!15!black},
every x tick label/.append style={font=\color{white!15!black}},
xmin=0, xmax=1,
ymin=-60, ymax=0,
xtick={0, 0.25, 0.5, 0.75, 1},
xticklabels ={$0$, $\pi/4$, $\pi/2$, $3\pi/4$, $\pi$},
ymajorgrids,
every outer y axis line/.append style={white!15!black},
every y tick label/.append style={font=\color{white!15!black}},
legend style={draw=white!15!black,fill=white,legend cell align=left, at={(axis cs: 1.05, -5)}}]

\addplot [smooth, color=black, solid, line width=2pt] table[x index=0,y index=1] {figs/data/imp_invar_FIR_butter_fir_mag_Hc.dat}; \addlegendentry{$H_{eq}(j\Omega)$};

\addplot [smooth, color=red2, solid, line width=2pt]
table[x index=0,y index=1] {figs/data/imp_invar_FIR_butter_fir_mag_Hfir.dat}; \addlegendentry{$H(e^{j\omega})$ FIR 25 samples};

\only<2-|handout:0> {
\addplot [smooth, color=blue2, solid, line width=2pt]
table[x index=0,y index=1] {figs/data/imp_invar_FIR_butter_fir_mag10_Hfir.dat}; \addlegendentry{$H(e^{j\omega})$ FIR 10 samples};
}

\only<3-|handout:0> {
	
	\addplot [smooth, color=black, solid, line width=2pt, forget plot] table[x index=0,y index=1] {figs/data/imp_invar_FIR_butter_fir_mag_T2_Hc.dat};
	
	\addplot [smooth, color=green2, solid, line width=2pt]
	table[x index=0,y index=1] {figs/data/imp_invar_FIR_butter_fir_mag_T2_Hfir.dat}; \addlegendentry{$H(e^{j\omega})$ $T_2 = 0.5T$};
}

\end{axis}
\end{tikzpicture}