Related Experiment Video
Updated: Jun 2, 2026

11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Digital simulation of an arbitrary stationary stochastic process by spectral representation
Harold T Yura1, Steen G Hanson
1Electronics and Photonics Laboratory, The Aerospace Corporation, Los Angeles, California 90009, USA.
Summary
This study introduces a fast method to generate random samples with specific probability distributions and spectral content. A single inverse transform step efficiently creates accurate simulations for various applications.
Area of Science:
- Signal Processing
- Computational Physics
- Statistical Modeling
Background:
- Generating discrete samples with specific probability density functions (PDFs) and spectral content is crucial for simulations.
- Existing methods often rely on complex autoregressive or iterative techniques, limiting efficiency and applicability.
Purpose of the Study:
- To present a computationally fast and straightforward method for synthesizing discrete samples with arbitrary PDFs and specified spectral content.
- To demonstrate the efficacy of a single inverse transform application for achieving accurate simulations.
Main Methods:
- Transforming white noise (Gaussian distributed) samples to match a desired spectral distribution.
- Applying an inverse transform to the spectrally shaped Gaussian distribution to achieve the target PDF.
- Analyzing the accuracy and limitations of the single-application inverse transform method.
Main Results:
- A single inverse transform application yields satisfactory results for a wide range of arbitrary PDFs and target power spectra.
- The method is computationally efficient and fast, suitable for generating large sample sets.
- While not perfectly conserving power spectra, the method provides accurate engineering approximations for system simulations.
Conclusions:
- The presented method offers an efficient and accurate approach for simulating random processes with desired statistical and spectral properties.
- The technique is applicable to a broad range of probability distributions and power spectra, with demonstrated relevance in optics.
- The method shows potential for extension to non-stationary random processes.
Related Concept Videos
State Space Representation
The frequency-domain technique, commonly used in analyzing and designing feedback control systems, is effective for linear, time-invariant systems. However, it falls short when dealing with nonlinear, time-varying, and multiple-input multiple-output systems. The time-domain or state-space approach addresses these limitations by utilizing state variables to construct simultaneous, first-order differential equations, known as state equations, for an nth-order system.
Consider an RLC circuit, a...
Consider an RLC circuit, a...
Sampling Theorem
In signal processing, the analysis of continuous-time signals, denoted as x(t), often involves sampling techniques to convert these signals into discrete-time signals. This process is essential for digital representation and manipulation. A critical component in sampling is the train of impulses, characterized by the sampling interval and the sampling frequency. The relationship between these parameters and the original signal's properties dictates the success of the sampling process.
Aliasing
Accurate signal sampling and reconstruction are crucial in various signal-processing applications. A time-domain signal's spectrum can be revealed using its Fourier transform. When this signal is sampled at a specific frequency, it results in multiple scaled replicas of the original spectrum in the frequency domain. The spacing of these replicas is determined by the sampling frequency.
If the sampling frequency is below the Nyquist rate, these replicas overlap, preventing the original signal...
If the sampling frequency is below the Nyquist rate, these replicas overlap, preventing the original signal...
Reconstruction of Signal using Interpolation
Signal processing techniques are essential for accurately converting continuous signals to digital formats and vice versa. When a continuous signal is sampled with a period T, the resulting sampled signal exhibits replicas of the original spectrum in the frequency domain, spaced at intervals equal to the sampling frequency. To handle this sampled signal, a zero-order hold method can be applied, which creates a piecewise constant signal by retaining each sample's value until the next sampling...
Discrete-Time Fourier Series
The Discrete-Time Fourier Series (DTFS) is a fundamental concept in signal processing, serving as the discrete-time counterpart to the continuous-time Fourier series. It allows for the representation and analysis of discrete-time periodic signals in terms of their frequency components. Unlike its continuous counterpart, which utilizes integrals, the calculation of DTFS expansion coefficients involves summations due to the discrete nature of the signal.
For a discrete-time periodic signal x[n]...
For a discrete-time periodic signal x[n]...
Sampling Continuous Time Signal
In signal processing, a continuous-time signal can be sampled using an impulse-train sampling technique, followed by the zero-order hold method. Impulse-train sampling involves the use of a periodic impulse train, which consists of a series of delta functions spaced at regular intervals determined by the sampling period. When a continuous-time signal is multiplied by this impulse train, it generates impulses with amplitudes corresponding to the signal's values at the sampling points.
In the...
In the...