Reply to J. L. Beck's “comments on ‘covariance-invariant digital filtering—a better digital processing technique for ground motion studies’”

1982 ◽  
Vol 72 (4) ◽  
pp. 1447-1447
Author(s):  
J. E. Ehrenberg ◽  
E. N. Hernandez
1981 ◽  
Vol 71 (4) ◽  
pp. 1361-1367
Author(s):  
J. E. Ehrenberg ◽  
E. N. Hernandez

abstract This paper describes a new recursive digital algorithm for computing the response spectrum from acceleration data. The algorithm digitally implements a single degree of freedom oscillator using a covariance-invariant digital filter. It is shown that this technique will produce an accurate response spectrum from input data that have been sampled at a rate that is as low as three times the oscillator natural frequency, fn. The more common response spectrum digital filter obtained using a bilinear z transformation technique requires a sampling rate of ten times fn. The fact that the algorithm can be used for data with a low sampling rate makes it particularly well suited for real time, multi-frequency calculation of response spectra with a microprocessor system.


1956 ◽  
Author(s):  
William R. Perret
Keyword(s):  

1975 ◽  
Vol 27 (4) ◽  
pp. 631-639
Author(s):  
E. D. Alcock
Keyword(s):  

2012 ◽  
Vol 12 (4) ◽  
pp. 66-76 ◽  
Author(s):  
Lyubka Doukovska ◽  
Venko Petkov ◽  
Emil Mihailov ◽  
Svetla Vassileva

Abstract The paper presents an overview of the image-processing techniques. The set of basic theoretical instruments includes methods of mathematical analysis, linear algebra, probability theory and mathematical statistics, theory of digital processing of one-dimensional and multidimensional signals, wavelet-transforms and theory of information. This paper describes a methodology that aims to detect and diagnose faults, using thermographs approaches for the digital image processing technique.


Geophysics ◽  
1967 ◽  
Vol 32 (6) ◽  
pp. 988-1002 ◽  
Author(s):  
Daniel Silverman

The paper discusses the background of the problem of signal and noise in the seismic process, and the application of the principles of communication theory to this problem. The limitations of the seismic process are discussed along with the types of noises involved, the methods of rejecting noise, the use of filters to reduce noise, characteristics of filters, and the relationships between frequency domain, time domain, mathematical, and digital filters. In the discussion of the electronic data processing of seismic information, the characteristics of an ideal seismic digital computer system are developed in relation to the characteristics of seismic data. The choice between digital and analog field recording is discussed in relation to the needs of the seismic process and the quality of the seismic data. Among the mathematical processes discussed are velocity filtering and a number of types of Wiener filtering, including horizontal stacking, deghosting, deconvolution, and multitrace digital filtering.


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