Signal processing

In electrical engineering and control theory, a Bode plot /ˈboʊdi/ is a graph of the frequency response of a system.

Negative feedback occurs when some function of the output of a system, process, or mechanism is fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances.

In electrical engineering, a sinusoid with angle modulation can be decomposed into, or synthesized from, two amplitude-modulated sinusoids that are offset in phase by one-quarter cycle (π/2 radians).

The power spectrum of a time series describes the distribution of power into frequency components composing that signal.

Estimation theory is a branch of statistics that deals with estimating the values of parameters based on measured empirical data that has a random component.

(For a broader coverage related to this topic, see Signal (electronics).) An analog signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.

A signal as referred to in communication systems, signal processing, and electrical engineering is a function that "conveys information about the behavior or attributes of some phenomenon".

A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities.

Bandwidth is the difference between the upper and lower frequencies in a continuous set of frequencies.

A chirp is a signal in which the frequency increases (up-chirp) or decreases (down-chirp) with time.

In computer graphics and digital imaging, scaling refers to the resizing of a digital image.

A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument.

In signal processing, the impulse response, or impulse response function (IRF), of a dynamic system is its output when presented with a brief input signal, called an impulse.

In mathematics, a wavelet series is a representation of a square-integrable (real- or complex-valued) function by a certain orthonormal series generated by a wavelet.

In communications and information processing, code is a system of rules to convert information—such as a letter, word, sound, image, or gesture—into another form or representation, sometimes shortened or secret, for communication through a channel or storage in a medium.

In mathematics and signal processing, an analytic signal is a complex-valued function that has no negative frequency components.

The short-time Fourier transform (STFT), or alternatively short-term Fourier transform, is a Fourier-related transform used to determine the sinusoidal frequency and phase content of local sections of a signal as it changes over time.

In signal processing, sampling is the reduction of a continuous signal to a discrete signal.

In signal processing, a window function (also known as an apodization function or tapering function) is a mathematical function that is zero-valued outside of some chosen interval.

Baseband is a signal that has a very narrow frequency range, i.

In mathematics and in signal processing, the Hilbert transform is a linear operator that takes a function, u(t), and produces a function, H(u)(t), with the same domain.

In signal processing and related disciplines, aliasing is an effect that causes different signals to become indistinguishable (or aliases of one another) when sampled.

In probability and statistics, given two stochastic processes and , the cross-covariance is a function that gives the covariance of one process with the other at pairs of time points.