中文摘要：

针对江河水下金属管线埋深探测需求，作者基于人工源电磁探测原理设计了水下金属管线探测仪，接收机中的窄带带通滤波器可从含有强噪声的混合信号中，很好地分离出特定频率的信号．作者推导了窄带带通滤波器的传递函数，进行了计算机仿真，并在仪器样机中得以应用．实验结果表明，优化设计的带通滤波器的中心频率误差小，通带内增益稳定，性能优良．

英文摘要：

An underwater metal pipeline detector is designed based on the principle of artificial source electromagnetic detection, which is used for detecting the deeply buried in underwater metal pipes. Narrowband band-pass filter in the receiver can well separate the specific frequency signal from mixed signal which is containing strong noise. Authors deduced the narrowband filter transfer function and simulated in computer, and the detector was applied in instrument prototype. Experiment results show that the error of the center frequency of the band-pass filter is small, and the gain is stable. In conclusion the detector has good performance.