$$\begin{gathered} \mathrm{restart}\: \\ \mathrm{with}\left(\mathrm{DynamicSystems}\right)\: \end{gathered}$$

$\mathrm{tf}≔\frac{s}{a\cdot s^2\+b\cdot s\+c}\:$

$\mathrm{sysTF}≔\mathrm{TransferFunction}\left(\mathrm{tf}\,\mathrm{parameters}\=\left[a\=1\,b\=1\,c\=1\right]\right)$

$\mathrm{sysTF}≔\left[\begin{array}{c}\mathbf{Transfer\; Function}\\ \mathrm{continuous}\\ \mathrm{1\; output(s);\; 1\; input(s)}\\ \mathrm{inputvariable}\=\left[\mathrm{u1}\left(s\right)\right]\\ \mathrm{outputvariable}\=\left[\mathrm{y1}\left(s\right)\right]\end{array}\right.$

$\mathrm{PhasePlot}\left(\mathrm{sysTF}\,\mathrm{parameters}\=\left[a\=3\,b\=4\,c\=5\right]\right)$

$\mathrm{sysDE}≔\mathrm{DiffEquation}\left(\mathrm{tf}\right)$

$\mathrm{sysDE}≔\left[\begin{array}{c}\mathbf{Diff.\; Equation}\\ \mathrm{continuous}\\ \mathrm{1\; output(s);\; 1\; input(s)}\\ \mathrm{inputvariable}\=\left[\mathrm{u1}\left(t\right)\right]\\ \mathrm{outputvariable}\=\left[\mathrm{y1}\left(t\right)\right]\end{array}\right.$

$\mathrm{sysDE}:-\mathrm{de}$

$\left[\frac{\ⅆ}{\ⅆt}\mathrm{x1}\left(t\right)=-\frac{a\mathrm{x2}\left(t\right)}{b}\,\frac{\ⅆ}{\ⅆt}\mathrm{x2}\left(t\right)=\frac{cb\mathrm{x1}\left(t\right)}{a^2}-\frac{b\mathrm{x2}\left(t\right)}{a}-\frac{b\mathrm{u1}\left(t\right)}{a}\,\mathrm{y1}\left(t\right)=-\frac{\mathrm{x2}\left(t\right)}{b}\right]$

$$\begin{gathered} \mathrm{Ts}≔0.025\: \\ \mathrm{Ns}≔1000\: \end{gathered}$$

$\mathrm{NoisyInput}≔\mathrm{Chirp}\left(1\,0.02\,0.01\,\mathrm{hertz}\=\mathrm{true}\,\mathrm{discrete}\=\mathrm{true}\,\mathrm{samplecount}\=\mathrm{Ns}\,\mathrm{sampletime}\=\mathrm{Ts}\right)\+\mathrm{Statistics}:-\mathrm{Sample}{\left(\mathrm{Normal}\left(0\,0.05\right)\,\mathrm{Ns}\right)}^{\mathrm{\%T}}\:$

$\mathrm{sysTFD}≔\mathrm{ToDiscrete}\left(\mathrm{sysTF}\,\mathrm{Ts}\right)$

$\mathrm{sysTFD}≔\left[\begin{array}{c}\mathbf{Transfer\; Function}\\ \mathrm{discrete;\; sampletime\; =\; .25e-1}\\ \mathrm{1\; output(s);\; 1\; input(s)}\\ \mathrm{inputvariable}\=\left[\mathrm{u1}\left(z\right)\right]\\ \mathrm{outputvariable}\=\left[\mathrm{y1}\left(z\right)\right]\end{array}\right.$

$\mathrm{OutputResponse}≔\mathrm{Simulate}\left(\mathrm{sysTFD}\, \left[\mathrm{NoisyInput}\right]\, \mathrm{parameters}\=\left[a\=1\,b\=1\,c\=1\right]\right)\left[\right]$

$\mathrm{plot}\left(\left[\mathrm{seq}\left(\left[\left(i-1\right)\cdot \mathrm{Ts}\,\mathrm{OutputResponse}\left[i\right]\right]\,i\=1..\mathrm{Ns}\right)\right]\right)$