Coupling to Shielded Cables — Lesson 3

This lesson covers the concept of crosstalk and near field coupling, focusing on the combination of capacitive coupling, inductive coupling, and common impedance coupling. It explains the equivalent circuit model for capacitive and inductive coupling and discusses how to approach it. The lesson also delves into the frequency domain and the role of series inductors and parallel capacitors. It further explains the conditions under which these elements can be neglected. The lesson provides a detailed analysis of the model, highlighting the differences between near end and far end crosstalk. It concludes with a discussion on common impedance coupling and its impact on near end and far end crosstalk.

Video Highlights

00:12 - Combination of capacitive coupling, inductive coupling, and common impedance coupling
04:31 - Reduced model after neglecting the capacitance and the series inductance
10:17 - Crosstalk voltages at near end and far end
13:43 - Near end crosstalk and far end crosstalk due to common impedance coupling

Key Takeaways

- Crosstalk is a combination of capacitive coupling, inductive coupling, and common impedance coupling.
- The equivalent circuit model for capacitive and inductive coupling can be approached by ignoring certain parts.
- Series inductors and parallel capacitors play a significant role in the model.
- Near end and far end crosstalk are different, with the near end crosstalk usually being higher.
- Common impedance coupling can increase both near end and far end crosstalk, depending on whether inductive or capacitive coupling is dominant.