海底大地电磁探测仪的测试方法
来源期刊：中南大学学报(自然科学版)2002年第4期
论文作者：陈儒军 白宜诚 崔燕丽 邓明
文章页码：344 - 347
关键词：随机信号;线性系统;海底大地电磁探测仪;频谱分析
Key words：random signal; linear system; ocean-bottommagnetotelluric instrument; spectral analysis
摘 要：根据海底大地电磁仪的特点,利用随机信号和线性系统理论,提出了快速可靠地测试仪器各通道幅谱特性、相频特性、噪声、信噪比等参数的方法.对于仪器的中高频段,采用一定带宽的正弦扫描信号作为测试的激励信号;在仪器的低频段和超低频率,商用信号发生器无法产生相应的正弦扫描信号,采用带宽的2n系列伪随机信号作为测试的激励信号,通过几次测量就能完成仪器在整个工作频率范围内的测试工作.此外,开发了相应的测试软件,能自动计算电道和磁道在一定频率范围内的测试参数,使用方便、简单、快捷.
Abstract: Ocean-bottom magnetotelluric instrument is awide band instrument which is used to record magnetotelluric signal with frequency ranging from 0.000 1 Hz to several hundred Hz, and takes a long time. Based on characteristics of newly developed ocean-bottom magnetotelluric instrument, using the theory of linear system and multi-channel spectral analysis of random signal, the authors develop a fast and reliable way to test amplitude spectra, phase spectra, noise power and signal to noise ratio of each channel of instrument. Sweep sinusoid signal is used to test the middle and high frequencyband of instrument, and at low and ultra-low frequency, commercial signal generator can′tgenerate corresponding sweep sinusoid signal, therefore, 2n series pseudo-random signal with controllable bandwidth is used as exciting signal. The whole frequency range can be covered by several measurements. At the same time, corresponding testing software, which calculates testing parameters in given frequency range of electrical and magnetic channel automatically, is developed. The testing results are in agreement with those of traditional methods.
