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1.
Summary The amplitude and phase responses of electromagnetic seismographs with an arbitrary number of galvanometers, used to increase the dynamic range of the seismograph or to filter perturbing oscillations, are derived. The fundamental parameters of the system, i.e. the partial periods and the partial constants of damping of the seismometer and of the individual galvanometers, together with the coupling terms, are replaced by other constants. These enable the responses of each channel to be computed with the aid of a combination of elementary responses of the systems of the set with zero couplings between the galvanometers and a zero effect of the motion of the galvanometers on the motion of the seismometer. The elementary responses are defined by 2 types of substitute constants: equivalent constants, determined by the roots of the characteristic equation, or by the partial periods, and reduced damping constants. The possibilities of analysing a system with equivalent constants are demonstrated on the case of a seismograph with 2 galvanometers. 相似文献
2.
Summary Every electromagnetic seismograph provides a record in the high-frequency range proportional to the time integration of the ground displacement. An intentionally extending this part of the amplitude characteristic of the integrator can be achieved when the equivalent periods of the seismometer and galvanometer are equal by a suitable combination of the equivalent damping constants: for integrator A, D
1
=0.383 and D
2
=0.924, for integrator B, D
1
=D
2
=0.650. The partial constants required to carry this out are given in Tabs 1 and 2. The equivalent period of the system with a shorter partial period increases with increasing coupling, the most in comparison with broad-band seismographs with a constant sensitivity for displacement, velocity and acceleration. This is convenient for long-period seismographs, if the seismometer has a shorter partial period than the galvanometer. An extension of its effective period can be achieved without deteriorating the mechanical stability of the seismometer, however, the effective period of the galvanometer decreases simultaneously. 相似文献
3.
Determination of a seismometer’s generator constant, azimuth, and orthogonality in three-dimensional space using a reference seismometer 总被引:2,自引:0,他引:2
To accurately predict the performance of a seismometer, knowledge of its key parameters is required. We present a new method that requires a single reference instrument to estimate some of the important parameters of the seismometer, such as the ratio of the generator constants, the orthogonality deviation, and the rotation in space and in the horizontal plane with regards to the reference instrument. The procedure is performed in the three-dimensional spaces where the Euler rotation theorem is applied in order to define a transformation, which is then used to transform the detection of the reference seismometer as well as the detection of the instrument under test. The estimated transformation matrix is defined as an upper triangular matrix, where its elements contain the information regarding the parameters of the tested seismometer, which are then evaluated using the Euler angles. The new method has been verified on a pair consisting of two STS-2 seismometers and on a pair consisting of one CMG-3T and one STS-2 seismometer. 相似文献
4.
A new method is presented for the self-noise estimation of a seismometer using a single, side-by-side, reference instrument
and taking into consideration the misalignment in the orientation of both seismometers. The self-noise of seismometers is
extracted directly from the measurements without using any information relating to the transfer functions. This procedure
can be applied if the self-noise of the reference seismometer is well known and defined, or if the self-noise of the reference
seismometer is sufficiently below the self-noise of the tested instrument and can be neglected. The latter case applies to
this study. An algorithm is also developed where we apply self-noise data in order to determine the orientation misalignment
between two seismometers, which is then resolved in three-dimensional space. This new method provides an estimate of the self-noise
and can also be used to extract some parameters of the installed seismic system in comparison with the reference seismic system,
such as generator constants and seismometer orientation or to eliminate unwanted noise sources, which have their origin in
the seismic station’s design. The new technique was applied to the CMG-3ESPC and CMG-40T seismometers, where an STS-2 instrument
served as the reference seismometer. 相似文献
5.
分析了相邻井下、地表地震计记录的背景噪声及近震、远震波形特征,以及相关的振幅谱及近震、远震接收函数波形特征。结果表明,井下地震计记录的背景噪声比地表地震计小1个数量级,其近震、远震波形记录较清晰、简洁;井下、地表地震计记录的远震振幅谱和径向接收函数具有较好的一致性,但背景噪声、近震振幅谱、近震接收函数、远震切向接收函数波形存在一定差异;由地表地震计得到的近震震级比井下地震计的大0.12,地表地震计到井下地震计之间的P波速度约为2 km/s。 相似文献
6.
提出基于阶跃响应在时域解析测定地震计参数的方法,并对合理确定响应的时间零点提供了一种方法。对JC-V100 3D型便携式短周期地震计及与其配套的EDAS-3M型16位地震数据采集记录仪组成的系统进行了测试。结果表明:对JC-V1003D短周期地震计的传递函数进行测试是可行的,对地震计的阻尼系数Dc和自振周期Tc的测试结果是令人满意的。 相似文献
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8.
The Russian electrodynamic seismometer model S-5-S has been adapted for the measurement of rotational ground motion. The mechanical system of the original S-5-S seismometer consists of electrodynamic sensing and damping transducer coils mounted on an asymmetrical double-arm pendulum. This pendulum is suspended on a footing using two pairs of crossed flat springs, which operate as the axis of rotation. The pendulum is stabilised by an additional spring. The S-5-S can be used either as a vertical or as a horizontal sensor. The adaptation of the S-5-S seismometer described below involves removal of the additional spring and installation of an additional mass on the damping arm. Strain gauge angle sensors are installed on one pair of the crossed flat springs. The main dynamic parameters of the rotational seismometer created in this way, i.e. the natural period and damping, are controlled electronically by feedback currents proportional to the angular displacement and angular velocity, both fed to the damping transducer coil. This new seismometer, named the S-5-SR, enables measurement of the rotational component of ground motion around the horizontal or the vertical axes. The output signal from this S-5-SR seismometer can be proportional either to rotational displacement or rotational velocity. 相似文献
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10.
R. E. Sarkgsyan 《Seismic Instruments》2014,50(3):244-245
The design of a modernized version of the SM-3 seismometer is described, in which the technical and operational characteristics of the seismometer are improved and its manufacturing costs are decreased. 相似文献
11.
根据吴开统等人提出的检验地震台网监测效能的几种方法,对临汾无线遥测台网的监控能力进行了检验,得出该遥测台网有较高观测精度的结论,找出了不足,提出了改进措施。 相似文献
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14.
在开环参数一定的条件下,速度传感反馈地震计中的环路滤波是影响地震计主要技术指标的关键环节之一.本文探讨了一阶极点高通、一阶极点低通、一阶零点高通、双一阶和零阶环路滤波在扩展地震计动态范围上限方面的优缺点.研究指出,对于用闭环反馈直接生成主导二阶极点的速度传感反馈地震计,一阶零点高通环路滤波的优点较多;若允许在环外生成主导二阶极点,则零阶环路滤波也不失为一个较好的方案. 相似文献
15.
A. LAMER 《Geophysical Prospecting》1970,18(2):300-319
The seismometer-ground system is represented by a damped oscillatory system. Relatively simple approximation formulas are derived to express the coupling between ground and seismometer. These expressions are applicable in seismic exploration. The coupling is that of a mass, suspended by a spring, to the surface that the ground would have in absence of the seismometer. It results in a low-pass filtering of the ground motion, which is due to the presence of the seismometer. This effect is expressed in a unit-impulse response. It appears that, over a sufficiently homogeneous ground and for low frequencies, one has a true coupling between ground and seismometer. To obtain a sufficiently large pass-band, a low seismometer housing-mass together with a not too small housing radius are necessary. 相似文献
16.
从理论上定量分析机械摆和环路滤波等开环诸参数变化对速度传感反馈地震计闭环参数的影响.研究指出,在环路设计中可半自由选取的开环阻尼取值对参数稳定性有重要影响.过大或过小的开环阻尼取值均可能造成参数稳定性急剧变差,影响地震计在只标不调的状况下长期连续稳定工作. 相似文献
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18.
介绍了利用地震计对阶跃电流标定或稳态正弦电流标定的响应波形获取地震计传递函数的方法。对阶跃标定电流的响应波形进行傅立叶变换(FFT)和扣除阶跃信号频谱的运算获得地震计的幅频特性;从稳态正弦标定电流的响应波形可直接提取幅频特性,然后用高斯牛顿迭代法拟合出地震计传递函数的各个系数。该方法的最大优点是只需要已知幅频特性或其有限离散点的数值就可以拟合出地震计的传递函数,较目前常用的需要同时已知幅频和相频特性的拟合方法更为方便和实用。 相似文献
19.
测震数采仪记录的钻孔应变 总被引:1,自引:1,他引:0
A seismometer data acquisition unit has been used in the Changping seismic station to record the output of a strainmeter.The output of a strainmeter was sampled at a rate of 100/sec by seismometer acquisition from the original rate of 1 per minute.Plenty of high frequency sampled data was recorded.The minute value curve calculated from the seismometer acquisition are consistent with that of the original data sampled by the strain acquisition system.More complete waveforms were recorded with a higher sampling rate,and seismic phase parameters calculated by using higher sampling rate strain seismic waves are also in consistency with the results of its predecessors.Spectra of the strain seismic waves are compared with that of seismic waves recorded by a seismometer in the Shisanling seismic station,and their trends are almost the same.Besides,some lower frequency components still exist in strain seismic waves. 相似文献
20.
地震计恒温低湿智能监控仪研制 总被引:1,自引:0,他引:1
摆房温度、湿度变化过大,地震计会出现靠摆、卡摆、标定不合格等故障现象,直接影响观测质量。为确保地震计工作环境恒温、低湿,观测数据连续、可靠,研制地震计低温低湿智能监控仪。 相似文献