Bode tool reports a state-space matrix and a Bode diagram of CoLink system. Bode tool computes a TF (transfer function) of CoLink system with a selected simulation time. And then it makes a Bode diagram. State-space matrix is a residual when Bode makes TF. Bode diagram is a graphically displaying method for frequency analysis. A variation of magnitude and phase delay is shown in logarithmic scales with growing frequency.
When the user uses the Bode tool, the CoLink system must be a RecurDyn plant block. Inputs of a CoLink system are defined outputs of a RecurDyn plant block. And also, Outputs of a CoLink system is the same inputs of a RecurDyn plant block. That’s why it needs a RecurDyn plant block.
First of all, the Bode tool makes a state-space matrix in order to get TF. State-space matrix is as Eq 1.
Figure 1 Definition of input and output
(1)
Where, 
,
,
are state variable vector, outputs and
inputs, respectively.
Therefore, a TF of CoLink system is computed as Eq 2.
(2)
For frequency analysis Bode tool is convenient to use 
. The 
is an imaginary number of complex and
called frequency. A variation of magnitude and phase delay is computed as Eq. 3.
with selected frequency 
.
(3)
The magnitude and phase are computed this sequence with growing input frequency. And The results are displaying in Bode diagram with logarithmic scales.