\documentclass{scrartcl}
\usepackage{color}
\usepackage{multicol}
\usepackage[final]{graphicx}
\usepackage{pst-plot,pstricks}
	\input{pstplot-logarithmic-axes}
\begin{document}
	\psset{xunit=2cm,yunit=0.1cm}
	\begin{pspicture}(-1,-10)(4,50)
		\psgrid[xunit=0.5,yunit=10,subgriddiv=0,griddots=5,gridlabels=0](-2,-1)(8,5)
		\psaxes[log=x,Dy=10]{->}(-1,0)(-1,-10)(4,50)
		\psplot[plotstyle=curve,linecolor=blue]{-1}{0}{0}
		\psplot[plotstyle=curve,linecolor=blue]{0}{1}{20 x mul}
		\psplot[plotstyle=curve,linecolor=blue]{1}{3}{20 1 mul}
		\psplot[plotstyle=curve,linecolor=blue]{3}{4}{20 x 2 sub mul}
		\rput[l](4,0){$\Omega=\frac{\omega}{\omega_0}$}
		\rput[r](-1.1,50){$\frac{\left|\underline{H}\left(j\omega\right)\right|}{dB}$}
	\end{pspicture}
\end{document}