Signal Processing Glossary

Distortion resulting from sampling a signal at a rate below twice its highest frequency, causing high-frequency components to appear as lower frequencies.

A continuous signal that varies smoothly over time, representing physical quantities like voltage, pressure, or temperature.

A function measuring the similarity between a signal and a time-shifted copy of itself, used to detect periodicity and estimate pitch.

The range of frequencies occupied by a signal or passed by a system, typically measured as the difference between the upper and lower frequency limits.

A mathematical operation that combines two signals to produce a third, expressing the output of an LTI system given its input and impulse response.

A logarithmic unit used to express the ratio of two quantities, commonly signal power or amplitude, defined as 10 * log10(P1/P2) for power.

A signal represented as a sequence of discrete numerical values, typically obtained by sampling and quantizing an analog signal.

A transform that converts a finite sequence of equally spaced samples into a finite sequence of equally spaced frequency components.

An efficient algorithm for computing the DFT that reduces the computational complexity from O(N^2) to O(N log N).

A digital filter with a finite-duration impulse response, implemented using only feedforward operations with no feedback loops.

A representation of a signal in terms of its frequency components rather than its time-varying amplitude.

A digital filter with a theoretically infinite-duration impulse response, implemented using both feedforward and feedback (recursive) operations.

The output of a linear time-invariant system when the input is a unit impulse, fully characterizing the system's behavior.

An integral transform used to convert continuous-time signals from the time domain to the complex frequency domain for system analysis.

A system satisfying both linearity (superposition) and time-invariance (a time shift in input produces an equal shift in output).

The minimum sampling rate required to avoid aliasing, equal to twice the highest frequency present in the signal.

A function describing how the power of a signal is distributed over frequency, measured in units of power per hertz.

The process of converting continuous amplitude values into a finite set of discrete levels, introducing a small error called quantization noise.

The process of converting a continuous-time signal into a discrete-time signal by recording its value at regular intervals.

The ratio of desired signal power to background noise power, typically expressed in decibels.

The spreading of a signal's frequency energy into adjacent bins during DFT analysis, caused by analyzing a finite-length signal segment.

A mathematical representation of the input-output relationship of an LTI system in the frequency or z-domain.

A time-frequency transform that uses scaled and shifted wavelets to analyze signals at multiple resolutions simultaneously.

Multiplying a signal segment by a tapering function before spectral analysis to reduce artifacts from signal truncation.

A discrete-time transform that maps a sequence of numbers into a function of the complex variable z, used for digital system analysis.