| General | When the distance between the differential lines is varied, The effect on crosstalk noise between two sets of differential signals was investigated. It is a standard function of Femtet with the interval between the differential lines as variable name dx. It is calculated by waving dx = 0.35, 1.0 by parametric analysis. |
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| Analysis Model | Two sets of differential line analysis models with differential vias are shown in Figure 1. The differential line analysis model is based on electromagnetic wave analysis example 22. Figure 2 shows an image of shaking the variable dx in parametric analysis. |
| Result | The far-end crosstalk frequency characteristics (Sd4d1) of the differential signal are shown in Figure 3. The near-end crosstalk frequency characteristics (Sd3d1) of the differential signal are shown in Figure 4. From the results in Figures 3 and 4, we can see how the smaller the differential track spacing, the larger the crosstalk. Figure 5 shows the TDR waveform. Because the shape of the differential track itself (Via diameter, track width, etc.) was not changed in this case, There is no difference between the two. |
| Keywords | Crosstalk Noise, Differential Transmission Lines, Differential Vias, TDR Waveforms |
