How can power line carrier PLC's power frequency filtering also ensure communication?

The power line carrier PLC power frequency filtering design needs to suppress 50/60Hz noise while ensuring smooth carrier communication. A complementary filtering strategy is adopted: an LC low-pass filter is deployed at the power input, using a PWR6045R6R8M0T (6.8μH) inductor and an X2 safety capacitor (0.47μF), with a cutoff frequency set at 150Hz to effectively filter out power frequency and its harmonics. Simultaneously, a high-pass filter is designed at the carrier coupling point, using a CBB capacitor (0.1μF) in series to block power frequency signals from entering the carrier circuit. The key is to use high-quality components in the filter design to reduce signal attenuation. Filter parameters are determined through simulation calculations to ensure that the insertion loss is less than 0.5dB in the carrier frequency band (e.g., 100-500kHz) and the attenuation is greater than 30dB at 50Hz. In actual testing, an oscilloscope is used to monitor the integrity of the carrier signal waveform to ensure that the modulation depth is not affected, achieving a balance between power frequency noise suppression and communication quality.