How to design a printed circuit board that meets the requirements of electromagnetic compatibility
When the signal operating frequency is greater than 10MHz, the ground impedance becomes very large, this time should try to reduce the ground impedance, should be used near the multi-point grounding.
In the ground design should pay attention to the following points: 1. The correct choice of single-point grounding and multi-point grounding In the low-frequency circuit, the signal operating frequency is less than 1MHz, its wiring and the inductance between the device less affected, and ground circuit Of the circulation of a greater impact on the interference, which should be a little ground.
Method Ground Design In electronic equipment, grounding is an important way to control interference. Such as grounding and shielding the correct combination of use, can solve most of the interference problem. Electronic equipment in the ground structure roughly systematically, chassis (shield), digital (logical) and analog ground
For example, if the two parallel lines of the printed circuit board are close together, a delay of the signal waveform is formed and a reflection noise is formed at the terminal of the transmission line. Therefore, in the design of printed circuit board, should pay attention to the use of the correct method.
Practice has proved that even if the circuit schematic design is correct, printed circuit board design is improper, but also the reliability of electronic equipment adversely affected.
