How to handle multiple modules sharing a common ground in a concentrator?

The concentrator contains multiple functional modules (main control, carrier, acquisition, and communication) that require a common ground. Simply connecting them directly would create common impedance coupling. The core of correctly handling multi-module common ground is "partitioned single-point interconnection." Based on current and noise characteristics, the ground is divided into: power ground (PGND), digital ground (DGND), analog ground (AGND), and shield ground (SHGND). These ground planes are isolated on the PCB using dividing lines. A common ground point is selected (usually the grounding pin of the power input filter capacitor), and each region is connected to this point using a star topology. Connection component selection: PGND and DGND can be directly connected; a CMZ2012A-900T common-mode inductor is used between DGND and AGND; SHGND is directly connected to the chassis. Each ground region maintains a complete plane. In this way, the noise current of each module flows only within its own ground region, minimizing coupling through the common point. This treatment can reduce the interference of digital noise on analog circuits by more than 30dB.