Simulating a Maximum Reference Chain

 Cascading the original ETSI model yielded the TDEV and MTIE plots shown in figures 8.10 and 8.11 respectively. All the results are for SEC's with B=1Hz.

 

Figure 8.10:   Wander at SEC output using original ETSI model

 

Figure 8.11:   MTIE after last SEC using original ETSI model

It can be seen from figure 8.10 that at small observation intervals, the noise exceeds the wander mask. The property of the PLL that has been neglected in this case in the ETSI model is that the PLL low pass filters the incoming noise. Hence the noise at high frequencies is actually reduced. This translates to suppressing noise at short observation intervals. Hence it can be seen that extending the model as proposed in section 5.4 and implemented in section 7.3 would reduce the noise at small $\tau$ an result in mask compliance.

The results for the simulation of maximum reference chain are presented in figures 8.12, 8.13, 8.14 and 8.15. It can be seen that File: thesis2.tex the PLL input noise filtering property indeed lowers the wander at short observation intervals and results in the network limit for wander not being exceeded.

 

Figure 8.12:   TDEV wander at SSU reference output

 

Figure 8.13:   MTIE wander at SSU reference output

 

Figure 8.14:   TDEV wander at SEC reference output

 

Figure 8.15:   MTIE wander at SEC reference output