Patent ID: 7920975

Claim:
A method of detecting anomalies in an ambient alternating current (AC) electric field generated by an AC power line, comprising the steps of: placing an AC electric field sensor in an ambient AC electric field generated by an AC power line; generating a signal representative of the ambient AC electric field received by the AC electric field sensor; and processing the signal to determine if any anomalies are present in the ambient AC electric field, said step of processing the signal includes the step of demodulating the signal with a synchronous demodulation circuit to generate a demodulated signal that includes portions representative of anomalies in the ambient AC electric field, wherein said synchronous demodulation circuit includes a mixer connected to a low pass filter and a high-gain amplifier connected to the mixer; the signal is fed to the mixer and the high-gain amplifier; and the demodulated signal is output by the low pass filter.