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Extending the Model

Section 5.4 proposed an extension to the ETSI model in order to include the effect of PLL filtering has on input noise.

**Figure 7.9:** Modification to ETSI model
$\begin{figure} \centerline{ \epsfig {file=eps/modelext.eps, width=10cm} }\end{figure}$

This model was implemented on SPW by generating two new clock blocks ssunew and secnew . The diagram of the extended model for a Synchronisation Supply Unit from the SPW Block Design Editor window is shown in figure 7.10.

**Figure 7.10:** Extended model of a SSU
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A similar process was carried out for the SDH Equipment Clock with a block symbol subsequently created for each entitled newssu and newsec . Since a Primary Reference Clock lies at the top of the chain, its model was left unchanged.

Mark J Ivens
11/13/1997