How to solve the internal signal crosstalk in HMI (Human Machine Delivery) systems?

To resolve signal crosstalk on the internal PCB of an HMI, prevention and control are needed from the aspects of layout, routing, and layer stack-up design. Crosstalk is an undesirable coupling between adjacent signal lines through mutual capacitance and inductance. First, during layout, signal lines with different characteristics should be grouped and isolated; for example, high-speed clock lines, high-speed data lines, analog signal lines, and noisy power lines should have separate routing areas. During routing, increasing the spacing between parallel traces is the most direct way to reduce crosstalk; the spacing should be at least three times the trace width. For sensitive signal lines, ground lines can be placed on both sides for isolation, i.e., "grounding".

Reducing the distance between signal lines and the reference ground plane can reduce their sensitivity to external radiation and interference. Avoid long parallel traces; if unavoidable, shorten the parallel length as much as possible. For critical high-speed differential pairs, maintain tight coupling; although this increases internal crosstalk, it reduces crosstalk to external and other line pairs. Using lossy dielectric materials or increasing the termination matching of signal lines can reduce reflections, thereby indirectly reducing crosstalk. Crosstalk levels can be pre-assessed using 3D field simulation in PCB design software. A well-designed stack-up, such as sandwiching a high-speed signal layer between two ground planes, provides the best crosstalk suppression. By following these design rules and optimizing the layout using audio electronics, signal crosstalk within the HMI can be minimized at its source.