标题： 通过自动特征提取和统计分析进行RFI检测 显示英文标题

标题： RFI detection by automated feature extraction and statistical analysis

摘要： 在本文中，我们介绍了一个干扰检测工具箱，由一个高动态范围的数字快速傅里叶变换光谱仪（DFFT，基于FPGA技术）和用于自动射频干扰（RFI）检测的数据分析软件组成。 DFFT光谱仪允许在小于一秒的时间尺度上高速存储光谱数据。 该设备的高动态范围确保了即使在极强的RFI事件期间也能保持恒定的校准。 软件使用一种算法，在时频域中执行二维基线拟合，自动搜索叠加在光谱数据上的RFI信号。 我们证明，该软件在计算机生成的RFI数据以及在埃费尔斯贝格100米望远镜记录的真实DFFT数据上都能成功运行。 在21厘米波长下，可以识别到4倍标准差级别的RFI信号。 对我们观测数据中检测到的所有RFI事件进行统计分析显示：（1）平均信号强度与银河系的天体线发射相当，（2）干扰是极化的，（3）望远镜附近的电子设备对RFI辐射有显著贡献。 我们还表明，在存在RFI信号的情况下，辐射计方程不再成立。 显示英文摘要

摘要： In this paper we present an interference detection toolbox consisting of a high dynamic range Digital Fast-Fourier-Transform spectrometer (DFFT, based on FPGA-technology) and data analysis software for automated radio frequency interference (RFI) detection. The DFFT spectrometer allows high speed data storage of spectra on time scales of less than a second. The high dynamic range of the device assures constant calibration even during extremely powerful RFI events. The software uses an algorithm which performs a two-dimensional baseline fit in the time-frequency domain, searching automatically for RFI signals superposed on the spectral data. We demonstrate, that the software operates successfully on computer-generated RFI data as well as on real DFFT data recorded at the Effelsberg 100-m telescope. At 21-cm wavelength RFI signals can be identified down to the 4-sigma level. A statistical analysis of all RFI events detected in our observational data revealed that: (1) mean signal strength is comparable to the astronomical line emission of the Milky Way, (2) interferences are polarised, (3) electronic devices in the neighbourhood of the telescope contribute significantly to the RFI radiation. We also show that the radiometer equation is no longer fulfilled in presence of RFI signals.