### FDN and State Space Descriptions

When in Eq.(2.10), the FDN (Fig.2.28) reduces to a normal*state-space model*(§1.3.7),

The matrix is the

*state transition matrix*. The vector holds the

*state variables*that determine the state of the system at time . The

*order*of a state-space system is equal to the number of state variables,

*i.e.*, the dimensionality of . The input and output signals have been trivially redefined as

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Time Varying Comb Filters