Several basic principles of signal integrity problems

1, any part of the interconnect, regardless of the length and shape of the line, and regardless of the rise time of the signal, is a signal path and return path consisting of a transmission line. A signal will feel a transient impedance every step along the transmission line. How the transient impedance is constant, as if the transmission line has a uniform cross-sectional area, the signal quality has a miraculous improvement.

2. Forget the term "grounded" because it creates more problems than it solves. Each signal has a return path. Catching the "return path" is like treating a signal to find and handle the return path, which helps to develop the intuitive ability to deal with problems.

3, when the voltage changes, the capacitance on the current flow. for the steep edge of the signal, even if the circuit

The edge line capacitance between the edge of the PCB board and the air gap between the dangling conductors may also have a very low impedance value. (This passage does not understand, please the great god to teach you!) )

4. There is an essential connection between the inductance and the number of turns of the magnetic field around the current. As long as the turns of the current or magnetic lines change, the voltage is generated at both ends of the wire. This voltage results in reflected noise, crosstalk, switching noise, ground bombs, orbital collapse (rail collapse), and EMI.

5, when the current flow through the grounding loop inductance, the voltage generated on the anti-Earth loop wire is called the ground bomb. It is the internal mechanism that causes switching noise and EMI. (This passage does not understand, please the great god to teach you!) )

6, with the same frequency of the square wave as a reference, the signal bandwidth refers to the effective sine wave component of the highest frequency value. The model's bandwidth is defined as the highest sine frequency, and the model is still able to accurately predict the actual performance of the interconnect. When using the model for analysis, be sure not to let the bandwidth of the signal exceed the bandwidth of the model.

7. The problem caused by lossy transmission line is that the rising edge is getting worse. Because of the skin effect and dielectric loss, the loss increases with increasing frequency. If the loss does not change as the frequency increases, then the rise time does not change, and the lossy line only adds some loss.

-----above from Eric Bogatin's signal Integrity analysis Book, we welcome you to study together

Several basic principles of signal integrity problems