How to avoid ground loops in a hybrid grounding system for power line carrier PLCs?

To avoid ground loops in power line carrier PLCs, a reasonable design is needed to combine low-frequency single-point grounding with high-frequency multi-point grounding. Low-frequency components (<1MHz), such as power supply ground and chassis ground, should use single-point grounding, with all ground wires converging at the power input to prevent low-frequency ground loops. High-frequency components (>1MHz), such as digital circuit ground and RF circuit ground, should use multi-point grounding, directly connected to the underlying ground plane through grounding vias to reduce ground impedance. Single-point and multi-point grounding should be connected via a PBZ1608A-102Z0T ferrite bead or an RC network (10Ω+100nF) to block high-frequency noise propagation. During layout, sensitive circuits should be kept away from grounding connection points to reduce coupling. Isolation devices such as the ADuM1410 digital isolator should be used to break signal ground loops. Grounding design should be optimized by analyzing ground loop current paths through simulation. In actual testing, a current probe should be used to measure the ground loop current; the optimized current should be less than 10mA. Hybrid grounding can effectively suppress ground loop interference by more than 30dB.