Research On Noise Reduction For Sensing Signals Of Integrated Optical Electric Field Detector By Means Of DSP Technology

With the rapid development of electronic and communication technology, electrical equipments and electronic products have been fully integrated into people’s production and living, which brought productivity progress and provided people with convenience. But at the same time, they always produce electromagnetic radiation and are faced with kinds of electromagnetic interference. In order to reduce the threat of electromagnetic radiation on human health and ensure stable operation of electronic and electrical equipments, we need to conduct electromagnetic environment measurement. When we use traditional electric field sensors to measure the electric field, the introduction of the probe will cause varying degrees of interference to the testing environment, which will lead to inaccurate results.The appearance of integrated optical waveguide electric field sensor is the perfect solution to this problem. It utilizes the Pockels effect of crystal. It can modulate the electromagnetic signal in the environment to the optical carrier of specific band and transmit for a distance, when demodulated by a photoelectric conversion module, we can recover the electrical signal. With its superior performance, integrated optical waveguide electric field sensor has been widely used in many fields, such as communication, electricity.The electrical field signal detected by the integrated optical waveguide electric sensing system is doped with some noise, and appears serious oscillation at the tail section, which will bring inconvenience to waveform analysis and processing later. So, some measures should be taken to reduce noise and retrieve the waveform.In this paper,1.2 μs/50 μs lightning high-voltage pulse signal is choosen as a typical waveform and analyzed, also, we designed a suit of DSP noise reduction system which consists of hardware and software, the system can realized real-time acquisition, capture, processing and output of integrated optical electric field sensor signal. Test results showed that, the designed system can complete the process of lightning high-voltage pulse signal and the noise reduction effect is obvious. On the basis of analysis of both the waveform and spectral components of original signal and sensor signal, referring to their characteristics, we choosed the FIR filter and the moving average method to deal with the the electric field sensing signal that we captured, After processing, we displayed the output waveform on the oscilloscope, and compared the original waveform and processed waveform.