How to avoid power line carrier frequency interference in PLCs?

Mitigating power line carrier frequency interference in PLCs requires a strategy combining frequency planning and filtering techniques. First, spectrum analysis is performed during the system design phase to select a less-interfered frequency band as the carrier frequency. On the hardware side, a bandpass filter is used at the carrier transmitter, with the center frequency precisely tuned to the carrier frequency; for example, a combination of an LC resonant circuit CMZ2012A-900T and a high-precision C0G capacitor is used. At the receiver, a high-Q selective amplifier is deployed to enhance sensitivity to the target frequency while suppressing out-of-band interference. Spread spectrum clocking technology is employed to address internal clock harmonic interference. On the software side, an adaptive frequency switching algorithm is implemented to automatically switch to a backup frequency band when excessive interference is detected in the current band. Through spectrum sensing and adaptive frequency tuning techniques, external interference can be effectively mitigated.