光栅多普勒效应新型地震检波器

Novel Seismometer Based on Grating Doppler Effect

传统地震检波器为“永磁动圈”式电磁检波器,在信号捡取过程中易受电磁干扰,存在非线性、动态范围小等问题.提出一种基于激光光栅多普勒效应的全新地震检波方法,依据谐波特性分析信号频谱,消除了光电接收器和电路噪声、环境波动等因素的影响,由差拍信号转折点的电压得到小于计数当量值的振幅值.实现了频率范围0.8Hz～500Hz,振幅20nm～2.0mm,相对误差小于100,其动态范围大于100dB.光栅多普勒地震检波器的信号质量好,消除了光源、运动速度及接收器之间的角度影响,提高了微小振动位移的测量精度、分辨率和动态范围.

The set-up of a conventional seismometer is a couple of permanent magnet and coil, which has a few troubles such as electromagnetic interference, permanent magnet′s non-linearity, and small dynamic range. A novel seismometer using grating Doppler effect is proposed. By analyzing the harmonious frequency of the beat wave the troubles of environmental fluctuation and noise produced by receiver circuits can be eliminated. By counting the voltages in the turning points of the beat wave, the amplitudes less than the equivalent value can be obtained.The vibration frequency is 0.8 Hz—500 Hz, and the amplitude is 20 nm—2.0 mm, the results present that the relative error is less than 100, and the dynamic range is larger than 100 dB.The signal quality of grating Doppler seismometer is excellent which is independent of the angle among the light sources, direction of the velocity and the receiver. It has promoted the survey accuracy, resolution and dynamic range.