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This paper proposes the use of random noise signals for the determination of the seismometers and accelerometers frequency response, as part of a device for device calibration which are the fundamental part of seismometric channel. The theory of the method is presented including mathematical relationship, considering these sensors as linear time invariant system (LTI) excited by stochastic signals and calculating the frequency response using these signals as a function of the Power Spectral Densities (PSD). Also, the main relationships and input - output equations defining the frequency response of these systems are shown and finally presented, for example, the calibration of very broad band sensor which is use extensive in seismic networks at national and international level. [ABSTRACT FROM AUTHOR]

The proposed objective was the design, characterization and setting in operation of a real time data acquisition system. Starting with L-4C type existent seismometer for which was implemented the software and hardware required to obtain the seismological registration station. The selected hardware was a National Instruments data acquisition card DAQ-516, this board has 8 analog input channels (16 bit) and 50 ks/s. The used software LabVIEW 6.0 was also National Instruments which is a graphic programming software that controls all card's data acquisition possibilities and additionally has powerful data handling tools. The other system components are a portable computer and a signal conditioning card. Once implemented and proven the data acquisition system, we proceeded to carry out the characterization of the system. Here the instrumental noise was determined, and the sensor was characterized for this a shaking table was designed and built. By means of an Internet connection, the system's internal clock synchronization is carried out by means of ATOMTIME 98 software. [ABSTRACT FROM AUTHOR]