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DSP Glossary

The terms that matter most in dsp development, with real-world context from DSPRelated's forums and blogs.

73 terms | The glossary grows by about 5 new entries per day.

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DSP Fundamentals
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All terms (A-Z)

A B C D E F G H I K L M N O P Q S T W Z
A
  • Adaptive Filter [adaptive] An adaptive filter is primarily a digital filter (analog implementations exist but are far less common) whose coefficients are automatically...
  • ADC [hardware] An analog-to-digital converter (ADC) is a peripheral or standalone IC that samples a continuous analog voltage (or current) and converts it ...
  • Aliasing [sampling-multirate] Aliasing is a distortion that occurs when a signal is sampled at a rate insufficient to uniquely represent its frequency content, causing fr...
  • All-Pass Filter [filters] An all-pass filter is a filter that passes all frequency components of a signal with (ideally) equal gain while introducing a frequency-depe...
  • Autocorrelation [spectral] Autocorrelation is the cross-correlation of a signal with a delayed copy of itself, producing a function that measures how similar the signa...
B
  • Bandwidth (signal) [fundamentals] Signal bandwidth is the span of frequencies occupied by a signal, typically measured in hertz (Hz) between defined lower and upper frequency...
  • Baseband [comms-dsp] Baseband refers to the original frequency range of a signal before it is modulated onto a carrier for transmission, or equivalently the freq...
  • Biquad Filter [filters] A biquad filter is a second-order recursive digital filter described by a transfer function with two poles and two zeros, implemented using ...
  • BPSK [comms-dsp]
C
  • CIC Filter [filters] A CIC (Cascaded Integrator-Comb) filter is a computationally efficient multirate filter structure built entirely from adders, subtractors, a...
  • Circular Convolution [algorithms] Circular convolution is the convolution of two sequences treated as if they are periodic with the same period N, rather than finite-length s...
  • Convolution [algorithms] Convolution is a mathematical operation that combines two sequences (or functions) to produce a third, expressing how one sequence modifies ...
  • Cross-Correlation [spectral] Cross-correlation measures the similarity between two signals as a function of a time lag applied to one of them, producing a sequence (or f...
D
  • DAC [hardware] A Digital-to-Analog Converter (DAC) is a peripheral or standalone IC that converts a discrete digital code into a proportional analog voltag...
  • DCT [transforms] The Discrete Cosine Transform (DCT) is a linear transform that expresses a finite sequence of data points as a sum of cosine functions oscil...
  • Decimation [sampling-multirate] Decimation is the process of reducing the sample rate of a discrete-time signal by retaining one out of every M samples, where M is the inte...
  • Deconvolution [algorithms] Deconvolution is the process of estimating an original signal from a measured output that has been distorted by a known (or estimated) convo...
  • DFT [transforms] The Discrete Fourier Transform (DFT) decomposes a finite sequence of equally spaced samples into a sum of complex sinusoids, producing a fre...
  • Dirichlet Kernel [spectral] The Dirichlet kernel is a trigonometric function defined as the sum of N complex exponentials equally spaced in frequency, evaluating to sin...
  • Dither (DSP) [numerics] Dither is a small amount of noise, typically random or pseudo-random, intentionally added to a signal at or before the quantization stage in...
  • DSP Processor [hardware] A DSP processor (digital signal processor) is a processor type optimized for the repetitive, numerically intensive arithmetic operations com...
  • DTMF [comms-dsp] Dual-Tone Multi-Frequency (DTMF) is a telephone signaling scheme in which each keypad symbol is represented by the simultaneous transmission...
E
  • Eb/No [comms-dsp] Eb/N0 (energy per bit to noise spectral density ratio) is a normalized measure used in digital communications to characterize the power effi...
F
G
  • GNU Radio [tools] GNU Radio is an open-source software framework and signal-processing toolkit for building software-defined radio (SDR) systems. It provides ...
  • Goertzel Algorithm [algorithms] The Goertzel algorithm is a recursive, block-based method for computing a single bin of the Discrete Fourier Transform (DFT), detecting the ...
  • Group Delay [fundamentals] Group delay is the negative derivative of a filter's or system's phase response with respect to frequency, representing how long different f...
H
  • Harmonics [spectral] Harmonics are frequency components in a signal at integer multiples of a fundamental frequency. In embedded signal processing, they appear i...
  • Hilbert Transform [transforms] The Hilbert transform is a linear operator that phase-shifts every frequency component of a real signal by 90 degrees (pi/2 radians), produc...
I
  • I/Q Signals [comms-dsp] I/Q signals refer to the in-phase (I) component and the quadrature (Q) component of a complex baseband signal: two representations of identi...
  • IFFT [transforms] The Inverse Fast Fourier Transform (IFFT) is an efficient algorithm that converts a frequency-domain representation back into a time-domain ...
  • IIR Filter [filters] An IIR (Infinite Impulse Response) filter is a discrete-time filter whose output depends on both current and past input samples and on past ...
  • Impulse Response [fundamentals] The impulse response of a linear time-invariant (LTI) system is the output produced when the input is a unit impulse (Dirac delta for contin...
  • Interpolation [sampling-multirate] Interpolation is the process of increasing the sample rate of a discrete-time signal by inserting new samples between existing ones, typical...
K
  • Kalman Filter [adaptive] A Kalman filter is a recursive Bayesian estimator that fuses a dynamic model of a system with noisy sensor measurements to produce an optima...
L
  • Linear Phase [filters] A filter has linear phase if its phase response is a linear function of frequency, meaning all frequency components of a signal are delayed ...
  • LMS Algorithm [adaptive] The Least Mean Squares (LMS) algorithm is an adaptive filter algorithm that iteratively updates filter coefficients to minimize the mean squ...
  • Low-Pass Filter [filters] A low-pass filter (LPF) is a filter that passes signal components below a defined cutoff frequency while attenuating components above it. It...
M
  • MATLAB [tools] MATLAB (a name derived from "Matrix Laboratory") is a commercial numerical computing environment and programming language from MathWorks, de...
N
  • NCO [comms-dsp] A Numerically-Controlled Oscillator (NCO) is a digital signal generator that produces a sine, cosine, or other periodic waveform at a freque...
  • NumPy [tools] NumPy (Numerical Python) is an open-source Python library that provides an efficient multi-dimensional array type (`ndarray`) along with a l...
  • Nyquist Rate [sampling-multirate] The Nyquist rate is the minimum sampling frequency required to represent a bandlimited signal without aliasing: it equals twice the highest ...
O
  • OFDM [comms-dsp] Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation scheme that splits a high-rate data stream across many narrow...
  • Oversampling [sampling-multirate] Oversampling is the practice of sampling or processing a signal at a rate significantly higher than the Nyquist rate (at least twice the sig...
P
  • Parks-McClellan [filters] Parks-McClellan is an iterative algorithm for designing equiripple (minimax) optimal linear-phase FIR filters by minimizing the maximum weig...
  • PCM [fundamentals] Pulse-Code Modulation (PCM) is a method of representing a continuously varying analog signal as a sequence of discrete digital samples, each...
  • Periodogram [spectral] A periodogram is an estimate of the power spectral density (PSD) of a signal, commonly computed by squaring the magnitude of the signal's di...
  • Phase (signal) [fundamentals] Phase is the offset of a periodic signal relative to a reference signal or waveform origin, expressed as an angle in degrees or radians. It ...
  • Phase-Locked Loop (DSP) [comms-dsp] A Phase-Locked Loop (PLL) is a feedback control system that drives a local oscillator to match the phase (and therefore frequency) of an inc...
  • Polyphase Filter [sampling-multirate] A polyphase filter refers to the multirate filter structure obtained by decomposing a prototype FIR filter (or, less commonly, an IIR filter...
  • Power Spectral Density [spectral]
Q
S
  • Sampling Rate [sampling-multirate] Sampling rate (also sample rate or sampling frequency, commonly denoted Fs) is the number of samples taken per second from a continuous-time...
  • SDR [hardware] Software-Defined Radio (SDR) is a radio communication architecture in which components traditionally implemented in dedicated analog or digi...
  • Sigma-Delta Modulation [sampling-multirate] Sigma-delta modulation (also called delta-sigma modulation) is a technique for converting analog signals to digital (or digital to analog) b...
  • SIMD [hardware] SIMD (Single Instruction Multiple Data) is a parallel execution model in which a single instruction operates on multiple data elements simul...
  • SNR [fundamentals] Signal-to-Noise Ratio (SNR) is the ratio of the power of a desired signal to the power of background noise in the same channel or measuremen...
  • Spectrogram [spectral] A spectrogram is a two-dimensional representation of how the frequency content of a signal evolves over time, typically displayed as a plot ...
  • STFT [transforms] The Short-Time Fourier Transform (STFT) is a technique that applies the Discrete Fourier Transform (DFT) repeatedly to short, overlapping se...
T
  • Time Domain [fundamentals] The time domain is a representation of a signal as a function of time, where the amplitude (voltage, current, or other physical quantity) is...
  • Transfer Function [fundamentals] A transfer function is a mathematical representation, typically expressed in the Laplace domain (s-domain) for continuous-time systems or th...
W
  • Wavelet Transform [transforms] The wavelet transform decomposes a signal into components localized in both time (or space) and scale (which relates to frequency, though th...
  • Welch Method [spectral] The Welch method is a technique for estimating the power spectral density (PSD) of a signal by computing averaged modified periodograms of o...
  • White Noise [spectral] White noise is a random signal whose power spectral density (PSD) is flat across all frequencies -- meaning every frequency band of equal wi...
  • Wiener Filter [adaptive] A Wiener filter is a linear, statistically optimal filter that minimizes the mean square error (MSE) between its output and a desired signal...
  • Window Function [filters] A window function is a finite-length weighting sequence applied to a block of time-domain samples before computing a Discrete Fourier Transf...
Z
  • Z-Transform [transforms] The Z-transform converts a discrete-time signal (a sequence of samples) into a complex-frequency-domain representation, expressed as a funct...