Spectral balancing in the time domain

Geophysics ◽  
1981 ◽  
Vol 46 (8) ◽  
pp. 1182-1188 ◽  
Author(s):  
D. Tufekčić ◽  
J. F. Claerbout ◽  
Z. Rašperić
Keyword(s):  
Time Domain ◽  
Seismic Data ◽  
Recent Interest ◽  
Definition Of ◽  
The Time Domain

The recent interest in deconvolution and the variety of new deconvolution methods in use demonstrates the importance and complexity of this problem. Each of the existing methods has some advantages for optimum enhancement of definition of seismic data. We believe that the spectral balancing method considered here is appropriate for data in which the frequencies of the organized noise are rather complex, e.g., land data shot by surface sources.

Discrete Time, Discrete Frequency

2021 ◽  
pp. 106-155
Author(s):  
Victor Lazzarini
Keyword(s):  
Signal Processing ◽  
Fourier Transform ◽  
Discrete Time ◽  
Time Domain ◽  
Continuous Time ◽  
Time Varying ◽  
Discrete Frequency ◽  
The Fourier Transform ◽  
Definition Of ◽  
The Time Domain

This chapter is dedicated to exploring a form of the Fourier transform that can be applied to digital waveforms, the discrete Fourier transform (DFT). The theory is introduced and discussed as a modification to the continuous-time transform, alongside the concept of windowing in the time domain. The fast Fourier transform is explored as an efficient algorithm for the computation of the DFT. The operation of discrete-time convolution is presented as a straight application of the DFT in musical signal processing. The chapter closes with a detailed look at time-varying convolution, which extends the principles developed earlier. The conclusion expands the definition of spectrum once more.

Depth-domain seismic reflectivity inversion with compressed sensing technique

2017 ◽  
Vol 5 (1) ◽  
pp. T1-T9 ◽  
Author(s):  
Rui Zhang ◽  
Kui Zhang ◽  
Jude E. Alekhue
Keyword(s):  
Compressed Sensing ◽  
Time Domain ◽  
Seismic Data ◽  
Reservoir Characterization ◽  
Synthetic Data ◽  
Seismic Inversion ◽  
Inversion Method ◽  
Depth Migration ◽  
Band Limited ◽  
The Time Domain

More and more seismic surveys produce 3D seismic images in the depth domain by using prestack depth migration methods, which can present a direct subsurface structure in the depth domain rather than in the time domain. This leads to the increasing need for applications of seismic inversion on the depth-imaged seismic data for reservoir characterization. To address this issue, we have developed a depth-domain seismic inversion method by using the compressed sensing technique with output of reflectivity and band-limited impedance without conversion to the time domain. The formulations of the seismic inversion in the depth domain are similar to time-domain methods, but they implement all the elements in depth domain, for example, a depth-domain seismic well tie. The developed method was first tested on synthetic data, showing great improvement of the resolution on inverted reflectivity. We later applied the method on a depth-migrated field data with well-log data validated, showing a great fit between them and also improved resolution on the inversion results, which demonstrates the feasibility and reliability of the proposed method on depth-domain seismic data.

scholarly journals Time-Depth Curve Evaluation Method for Conversion Time to Depth at Penobscot Field, Nova-Scotia, Canada

2017 ◽  
Vol 17 (1) ◽  
pp. 25
Author(s):  
Fitri Rizqi Azizah ◽  
Puguh Hiskiawan ◽  
Sri Hartanto
Keyword(s):  
Time Domain ◽  
Seismic Data ◽  
Evaluation Method ◽  
Seismic Survey ◽  
Seismic Exploration ◽  
Reflection Seismic ◽  
Conversion Time ◽  
Well Data ◽  
The Time Domain ◽  
Depth Curve

Oil and natural gas as a fossil fuel that is essential for human civilization, and included in nonrenewable energy, making this energy source is not easy for updated availability. So that it is necessary for exploration and exploitation reliable implementation. Seismic exploration becomes the method most widely applied in the oil, in particular reflection seismic exploration. Data wells (depth domain) and seismic data (time domain) of reflection seismic survey provides information wellbore within the timescale. As for the good interpretation needed information about the state of the earth and is able to accurately describe the actual situation (scale depth). Conversion time domain into the depth domain into things that need to be done in generating qualified exploration map. Method of time-depth curve to be the method most preferred by the geophysical interpreter, in addition to a fairly short turnaround times, also do not require a large budget. Through data information check-shot consisting of the well data and seismic data, which is then exchanged plotted, forming a curve time-depth curve, has been able to produce a map domain depth fairly reliable based on the validation value obtained in the range of 54 - 176m difference compared to the time domain maps previously generated.Keywords: Energy nonrenewable, survei seismik, peta domain waktu, peta domain kedalaman, time-depth curve

Time-domain inversion of GPR data containing attenuation due to conductive losses

Geophysics ◽  
2006 ◽  
Vol 71 (5) ◽  
pp. K103-K109 ◽  
Author(s):  
Qingyun Di ◽  
Meigen Zhang ◽  
Maioyue Wang
Keyword(s):  
Time Domain ◽  
Ground Penetrating Radar ◽  
Seismic Data ◽  
Random Noise ◽  
Synthetic Data ◽  
The Time Domain ◽  
Ground Penetrating ◽  
Domain Inversion ◽  
Inversion Techniques ◽  
And Inversion

Many seismic data processing and inversion techniques have been applied to ground-penetrating radar (GPR) data without including the wave field attenuation caused by conductive ground. Neglecting this attenuation often reduces inversion resolution. This paper introduces a GPR inversion technique that accounts for the effects of attenuation. The inversion is formulated in the time domain with the synthetic GPR waveforms calculated by a finite-element method (FEM). The Jacobian matrix can be computed efficiently with the same FEM forward modeling procedure. Synthetic data tests show that the inversion can generate high-resolution subsurface velocity profiles even with data containing strong random noise. The inversion can resolve small objects not readily visible in the waveforms. Further, the inversion yields a dielectric constant that can help to determine the types of material filling underground cavities.

Suspending the “Time Domain” : Technological Tempor(e)alities of Media Infrastructures

2021 ◽  
Author(s):  
Wolfgang Ernst
Keyword(s):  
Time Domain ◽  
Time Function ◽  
Archaeological Investigation ◽  
Temporal Structures ◽  
Definition Of ◽  
The Time Domain ◽  
Effects Of Media ◽  
Media Event

Any media event is a time function of signals. In favor of a diagrammatic definition of technological media, media archaeological investigation is not only concerned with their structural “hardwired” level but with their operative unfolding-in-time as well. Such an understanding of techno-temporalities does not focus on phenomenal effects of media on humans but primarily refers to the microregimes within technological devices. In that sense, “hardwired temporality” refers to the infrastructuring of time by technologies and to temporal structures which are revealed from within techno-logical knowledge itself. From that arises an epistemology of technical processuality beyond the conventional notion of “time.”

scholarly journals Cardiovascular control and time domain Granger causality: insights from selective autonomic blockade

2013 ◽  
Vol 371 (1997) ◽  
pp. 20120161 ◽  
Author(s):  
Alberto Porta ◽  
Paolo Castiglioni ◽  
Marco Di Rienzo ◽  
Tito Bassani ◽  
Vlasta Bari ◽  
...  
Keyword(s):  
Granger Causality ◽  
Time Domain ◽  
Closed Loop ◽  
Systolic Arterial Pressure ◽  
Cardiovascular Control ◽  
Causal Direction ◽  
Autonomic Blockade ◽  
Definition Of ◽  
The Time Domain ◽  
Bidirectional Interactions

We studied causal relations among heart period (HP), systolic arterial pressure (SAP) and respiration (R) according to the definition of Granger causality in the time domain. Autonomic pharmacological challenges were used to alter the complexity of cardiovascular control. Atropine (AT), propranolol and clonidine (CL) were administered to block muscarinic receptors, β-adrenergic receptors and centrally sympathetic outflow, respectively. We found that: (i) at baseline, HP and SAP interacted in a closed loop with a dominant causal direction from HP to SAP; (ii) pharmacological blockades did not alter the bidirectional closed-loop interactions between HP and SAP, but AT reduced the dominance of the causal direction from HP to SAP; (iii) at baseline, bidirectional interactions between HP and R were frequently found; (iv) the closed-loop relation between HP and R was unmodified by the administration of drugs; (v) at baseline, unidirectional interactions from R to SAP were often found; and (vi) while AT induced frequently an uncoupling between R and SAP, CL favoured bidirectional interactions. These results prove that time domain measures of Granger causality can contribute to the description of cardiovascular control by suggesting the temporal direction of the interactions and by separating different causality schemes (e.g. closed loop versus unidirectional relations).

scholarly journals Introduction to Communication Systems

2021 ◽  
pp. 1-17
Author(s):  
Stevan Berber
Keyword(s):  
Theoretical Analysis ◽  
Time Domain ◽  
Communication Systems ◽  
Theoretical Concepts ◽  
Analysis And Design ◽  
The Subject ◽  
Definition Of ◽  
The Time Domain ◽  
Analogue To Digital ◽  
Power And Energy

This chapter introduces the subject of the book, defines the main terms in communication systems that will be used in the book, and presents the objectives of the book. It also presents classifications of signals and systems, and theoretical concepts related to the signal conversions in the time domain that will be used in subsequent chapters. The signals are classified using various criteria, including periodicity and symmetry, continuity and discreteness, power and energy properties, randomness, and physical realizability of signals. Analogue-to digital and digital-to-analogue conversions and their places and importance in the processing of signals in relation to their application in communication systems are briefly explained. The final section returns back to the definition of the signals related to the continuity and discreteness in time and their values, due to the importance of distinguishing them in the theoretical analysis and design of digital and discrete communication systems.

Spectral Moments and Pre-Envelope Covariances of Nonseparable Processes

1990 ◽  
Vol 57 (1) ◽  
pp. 218-224 ◽  
Author(s):  
Mario Di Paola ◽  
Giovanni Petrucci
Keyword(s):  
Stochastic Process ◽  
Time Domain ◽  
Critical Review ◽  
Stationary Case ◽  
Spectral Moments ◽  
Definition Of ◽  
The Time Domain ◽  
Made In

A critical review of the definition of the spectral moments of a stochastic process in the nonstationary case is presented. An adequate time-domain representation of the spectral moments in the stationary case is first established, showing that the spectral moments are related to the variances of the stationary analytical pre-envelope processes. The extension to the nonstationary case is made in the time domain evaluating the covariances of the nonstationary pre-envelope showing the differences between the proposed definition and the classical one made introducing the evolutionary power.

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