【作者】 王广福； 于桂生； 周公威；

【Author】 Wang Guangfu Yu Guisheng (Institute of Geophysics,Chinese Academy of Sciences) Zhou Gongwei (Institute of Geophysics,State Seismological Bureau)

【机构】 中国科学院地球物理研究所； 国家地震局地球物理研究所；

【摘要】 本文根据最小相位系统判据,对目前我国地震台站普遍使用的几类地震仪做了分析并指出,这些仪器都是最小相位系统;最小相位系统的相频特性可由其幅频特性计算出来.作者按照"地震台站观测规范"规定,标定了DD-1型、DK-1型和基式地震仪的幅频特性.然后,用希尔伯特(Hilbert)变换由实测幅频特性计算了它们的相频特性.并把计算结果与用相位特性测试仪器实测的结果做了比较:对于DD-1型地震仪,在从0.0125 s到12.5 s的周期范围内,最大误差小于5°;对于DK-1地震仪,在从0.05 s到100 s的周期内,最大误差小于5°;对于基式地震仪,在从0.01 s到100 s的周期范围内,最大误差小于1.5°.这种方法可以解决台站仪器相频特性的标定问题.标定精度比快速傅里叶变换(FFT)方法和用近似解析表达式计算方法要高.应用这种方法的关键是能对被测系统幅频特性曲线高频段和低频段的斜率做出正确的判断.这种方法的误差取决于幅频特性曲线的标定精度.用插值方法计算,计算的尾差和截断误差可以不必考虑.更多还原

【Abstract】 On the basis of minimum-phase criterion analysis has been made for some kinds of seismographs which are now in common use at Chinese seismological stations.The result shows that such seismographs are minimum-phase systems.The phase responses may be calculated from their amplitude responses. According to The Operating Code for Seismological Observation promulgated by State Seismological Bureau the amplitude responses of the type DD-1,DK-1,and SK seismographs have been calibrated and their phase responses were calculated from these amplitude responses by the Hilbert transformation.The calculated phase responses were compared with that measured by a phasemeter.The maximum error was found to be less than 5°for type DD-1 and DK-1 seismographs in the period range form 0.0125 s to 12.5 s and 0.05 s to 100 s, respectively.For type SK seismograph in the period range of 0.01 s to 100 s the maximum error is less than 1.5°. This technique may be used to calibrate the seismograph phase response at the permanent staions.It is more accurate than the FFT method and the analytical method by means of approximate expression of a transfer function. The key to the use of this technique lies in the correct judgement of the slopes of the higher and lower frequency parts of the amplitude response curve.The error depends on the calibration accuracy of the amplitude response.By the use of interpolation the tail and the truncation error may be neglected.更多还原