Questions tagged [noise]
This tag is for questions about noise. In signal processing, noise is a general term for unwanted (and, in general, unknown) modifications that a signal may suffer during capture, storage, transmission, processing, or conversion.
231 questions
2 votes
0 answers
51 views
PDF of the classical bispectrum of Gaussian white noise
PDF of the bispectrum My goal is to find the PDF of the magnitude of the classical bispectrum $|\lambda_1|$ (I’ve given a definition a few lines below) in order to find 95% confidence intervals for ...
0 votes
0 answers
38 views
Generating and Interpreting the Allan Variance Sigma-Tau Diagram
The Allan Variance Sigma Tau Diagram allows one understand the different kinds of noise that are present in a time series; the following two images are taken from the wikipedia page related to Allan ...
4 votes
3 answers
251 views
How to dither binned data (following a geometric distribution) to recover the exponential distribution?
Consider a random variable 𝑋 that follows an exponential distribution. After binning (floor), 𝑋 becomes discrete and follows a geometric distribution. My question is: how can we recover the original ...
0 votes
1 answer
280 views
Connection Between Power Spectrum and Hurst Exponent [closed]
I'm analyzing a time series and estimating both the power spectrum exponent $ \beta $ and the Hurst exponent $ H $. According to the literature, these quantities are related by $ \beta = 2H - 1 $. ...
0 votes
0 answers
19 views
Statistical moments of noise - deriving third-order central moment of noise is equal to skewness
In An Introduction to Bispectral Analysis and Bilinear Time Series Models (Rao & Gabr, 1984), the authors derive the spectrum and bispectrum of a linear process represented by $$X_t = \sum^{\infty}...
0 votes
1 answer
48 views
Integration involving a random variable
How to approach this integral: $$I(t) = \int A \cos(\alpha t + \phi (t))dt$$ where $A$ and $\alpha$ are constant? $\phi (t)$ is modelled as a Wiener process (Gaussian distributed random variable ...
2 votes
1 answer
75 views
Behavior of Perturbed Functions with uniform noise
Let $f: \mathbb{R}^n \to \mathbb{R}$ be a continuous function, and let $\xi(x)$ be a uniformly distributed random variable with variance $\sigma^2 > 0$, independent and identically distributed (i.i....
1 vote
0 answers
47 views
Definition of Colored Noise in terms of White Noise
For context, I was reading Optimal Control and Estimation by Stengel. In a section centered around discussing colored noise, Stengel defines a first-order difference equation $$\tag{1}x_{i+1} = ax_i + ...
0 votes
1 answer
33 views
Distribution of Noisy Linear Dynamical System over time
Suppose we are given a linear dynamical system $$ x_t = Ax_{t - 1} + \mathcal{N}(0, \sigma^2) $$ where $A$ is orthogonal, $x_t \in \mathbb{R}^n$, and $\mathcal{N}(0, \sigma^2)$ is a normal ...
2 votes
1 answer
131 views
What would be $q$ in ARIMA(p,d,q) model for the following discrete-time transfer function model?
A general ARIMA(p,d,q) model is given by:$(1-B)^d\phi(B)X_t = \theta(B)a_t$ where p is the order of AR term:$\phi(B)=(1-\phi_1B-\phi_2B^2-\phi_pB^p)$ and d is the order of MA term: $\theta(B)=(1-\...
1 vote
0 answers
46 views
Time Average of a function of adjacent datapoints in a linear dynamical system
Suppose we are given a linear dynamical system $$ x_t = Ax_{t - 1} + \mathcal{N}(0, \sigma^2) $$ where $A$ is orthogonal, $x_t \in \mathbb{R}^n$, and $\mathcal{N}(0, \sigma^2)$ is a normal ...
5 votes
1 answer
333 views
How to numerically solve noisy ODE
I need to numerically integrate a large number of ODE's of the following form $$ \dot{X} = k_{1}\left[\rule{0pt}{4mm}U\left(t\right) - X\right] + k_{2}V\left(t\right)\left[\rule{0pt}{4mm}W\left(t\...
0 votes
0 answers
90 views
Why is the autocorrelation of an uncorrelated random noise process the dirac delta distribution?
I am reading Stochastic Methods by Gardiner and in the beginning of chapter 4 he motivates the rigorous interpretation of a Stochastic Differential equation by describing the properties of a "...
0 votes
1 answer
64 views
how to determine amplitude and frequency of Oscillator with random fluctuations?
I have the following system $$\ddot{x}+w^2 x=0,$$ with the following initial conditions: $\dot{x}(0)=0$ and $x(0)=x_o$, the solution reads: $$x(t)=x_o cos(t).$$ Now I want to include the fluctuations ...
1 vote
1 answer
71 views
Entropy of noisy continuous channel
I'm recently learning Shannon entropy. The discrete case seems to be easy to understand and I'm trying to apply it to the continuous case. Suppose a channel has discrete inputs $X$ and outputs $Y$ per ...