# Questions tagged [terminology]

For questions about words, phrases and definitions that are specific to signal processing.

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22 views

### Whats the technical term for a filter that allows a non unity stride when sliding it's window?

So a 1D mean filter of size two with a sliding window defined as W below could be considered as having a stride of one. Wn=(Xn + Xn+1) / 2 Vn=W2n where as if I were to define a 1D 'stepped ...
71 views

### Definitions of PSD, ESD and Autocorrelation

This question is going to encompass multiple areas and may not have a single answer but here it goes. I'm trying to conceptualize 3 different concepts and how they relate to each other. These 3 ...
54 views

### What word can I use to describe time-varying spectral content?

I have two devices that generate different classes of signals, one simple and one complex. I would like to find a single word or short phrase that describes the increased richness in one class ...
58 views

### Limiter, compressor, AGC, dynamics processor?

What are the primary differences between the usage or definitions of the terms “AGC”, “compressor”, “limiter”, and dynamics processor? They all seem to be forms of playing with gain knobs.
85 views

### Confused in difference between sequence versus signal?

I am learning basics of signals and systems with MATLAB If i create a vector in matlab such that x=[ 2 5 10 20], will it be considered a sequence or a signal? As ...
32 views

### What is the technical term for the product of “number of pixels” and “number of channel per pixel”?

Assume I have m x n pixels of an RGB image. If I calculate 3mn, what is the name of quantity for this value?
33 views

### System Response Terminology

If I have a system specified by $$P(D)y(t)=Q(D)x(t)$$ and I specify initial conditions $y(0^-)=a, \ y'(0^-)=b,\ x(0^-)=c$ does the term $x(0^-)=c$ correspond to the zero state response or zero ...
240 views

### What is energy in image processing?

There are several web articles on the topic, but, after having read them, I still don't know what "energy" is, in the context of computer vision (CV) and image processing (IP). It is related to ...
81 views

### What is the difference between domain and range filtering?

In the context of image processing, I have heard the expressions "domain filtering" and "range filtering". What do these terms refer to? What is the difference between them?
65 views

### What is a periodic signal in image processing?

In the context of image processing (and computer vision), the concept of convolution comes up a lot. Convolution is quite related to the concept of Fourier transform and DFT. In the context of image ...
56 views

### What is the relation between smoothing and blurring?

Is there any difference between smoothing and blurring? Are these two operations the same or do these terms refer to different operations?
17 views

### What is intuitively a diffusion in the context of images?

I have heard the word "diffusion" in the context of image processing and computer vision. However, images are discrete and I associate the word "diffusion" with a continuous process. Intuitively, what ...
85 views

### What is the relation between time, frequency, spatial and spectral domains?

What is the relation between time, frequency, spatial and spectral domains? I think that time and spatial domains are the "original" domains (e.g. if the signal is a greyscale image, then the domain ...
154 views

### What do we mean by spectrum?

Consider the context of image processing and computer vision, and, in particular, discrete Fourier transform. For example, in the sentence In the Discrete Time Fourier Transform the forward ...
90 views

### What is the difference between an impulse response and a kernel?

It seems to me they are two terms used to refer to the same concept, but, according to the Wikipedia page on Guassian filter a Gaussian filter is a filter whose impulse response is a Gaussian ...
85 views

### Is there any opposite name for Decibel?

According to definition of decibel it’s “logarithmic unit of measurement used to express” So in audio we often convert linear value from range 0 to 1 to logarithmic scale for example like that: <...
59 views

### difficulty in understanding amplitude, frequency and period

I have difficulty in understanding of some fundamental terms as amplitude. Can be there more than one amplitude for a signal? The following expression is combination of 3 sinusoidal signal, so are ...
209 views

### Quadrature demodulation, homodyne detection, lock-in detection - what's the difference?

Quadrature demodulation Homodyne detection Lock-in detection What is the difference between these terms? Are they all synonomous? In my mind they kind of are, so I'm never sure which to use. I ...
22 views

### Does Mutual information utilize spatial information to calculate image similarity?

To calculate images similarity based on Mutual Information (MI), histogram and join histogram is required. In the literature, there are 2 contradict opinions about MI operation. 1. MI does not utilize ...
87 views

### Is Oversampling a Signal Same as Discretizing the Signal?

I am confused about the new terminology 'oversampling' I have encountered very recently. To explain it better, I am going to use numerical examples. Now let's assume I am using a BPSK modulator and my ...
148 views

### Intuition behind cepstrum analysis terminology

In multiple books I found a parallel between spectrum-analysis terminology and cepstrum-analysis terminology that says low pass filter $\rightarrow$ short pass lifter I didn't read explicitly what ...
88 views

### What is the moment when all oscillators aligned to make a jump called?

Say we have a square wave and its Fourier series. When the wave doesn't jump, its oscillators aren't aligned: But if they are aligned, the wave will jump: What is this moment called? They might not ...
478 views

### Why is second-order Gaussian called Laplacian Gaussian?

We usually use Laplacian of Gaussian as the filter for edge detection or blob detection. But the filter itself is essentially a second order Gaussian. So why do we call it Laplacian of Gaussian? Is ...
145 views

### The precise meaning of 'coefficient' in signal processing

when I read papers on signal processing, I often see the term 'coefficient' being used to refer directly to 'samples', i.e. "We can reduce the number of coefficients, by simply subsampling the even ...
57 views

### Is there a name for the procedure of taking the FT over separate consecutive small time-blocks?

Suppose we have a continuous time-interval $I=[a,b]$, and a signal $x \colon I \to \mathbb{R}$. A procedure that is sometimes carried out (e.g. when doing bispectral analysis) is to partition $I$ ...
160 views

### Is there a name for $f(x) = |x|^n \cdot \operatorname{sgn}(x)$?

I'm looking for a name for the following function $$f(x) = |x|^n \cdot \operatorname{sgn}(x)$$ which is the exponent function, but with the sign stripped from the input and reattached to the output....
475 views

### When can the impulse response become zero?

The article Efficient Use Of Sparse Adaptive Filters (Proc. Asilomar Conference, Khong et al., 2006) introduces adaptive filters for the estimation of channels or systems having a sparse impulse ...
591 views

### What is the meaning of channel capacity?

If the transmitted information signal takes values from a modulation constellation, then is there a way to know what the channel capacity is? Is there a connection between the modulation kind and ...
105 views

### What is perfect and imperfect channel?

Often in estimation of the input signal to an unknown channel, the bit error rate is plotted as the performance measure. The curve is compared with an ideal curve labelled as 'Perfect channel'. For ...
44 views

### Confusion regarding model order and lags

I have similar questions as the one asked in these posts: https://stackoverflow.com/questions/47083890/fir-filter-length-is-the-intercept-included-as-a-coefficient-matlab/47085339?noredirect=1#...
83 views

### Why use parametric based estimation methods - confusion regarding terms

Using the probability density function (pdf) we can estimate an unknown parameter using methods such as Maximum Likelihood estimation. If the pdf is not available, then Least Squares can be used. ...
71 views

### Why maximum likelihood estimation method is taken as the benchmark for comparing with other methods?

In many research articles the performance of an estimation method is compared to that of the ML estimation performance. If the performance of the method does not achieve the ML estimation performance, ...
3k views

### Difference between order and length of a filter

Let, the channel be modeled as a FIR model with order L. Mathematically, $y_n = \sum_{k=1}^L h_k u_{n-k} \tag{1}$ where $u$ is the data input to the channel and <...
915 views

### SNR for complex valued signal and when to use SNR and when to use Eb/N0?

This question is in continuation to the one asked earlier Help in understanding the formula of Signal-to-Noise-Ratio (SNR) - Part 1 Consider a model $$y[n] = x[n] + w[n]$$ Signal means the desired ...
157 views

### What is Audio codec in simplified term?

I am trying to understand what a codec actually is Wikipedia says In hardware, audio codec refers to a single device that encodes analog audio as digital signals and decodes digital back ...
113 views

### Brief introduction to wireless communication and communication terminologies [closed]

In the Question Design of equalizer for wireless communication the diagram of a basic communication system is presented with informative points and discussions. My Questions are: Considering the ...
129 views

### Terminologies - lags, order in time series model

I am facing some difficulties with the terminologies - lag ($p$) and sequence length (number of data points) (N) used in time series model such as Moving average and Autoregressive model. Considering ...
110 views

### Is there a scientific name for this technique?

The following algorithm takes a set of signals, and return a complex number: For a given set of signals - $\{s_1(n),s_2(n),...,s_M(n)\}$, compute the DFT of each of them - \$\{S_1(k),S_2(k),...,S_M(k)\...
1k views

### Lloyd Max Quantization and Clustering : Part 1

The Lloyd-Max quantizer is a scalar quantizer which can be seen as a special case of a vector quantizer (VQ) designed with the Linde Buzo Gray (LBG) algorithm. In k-means clustering, we are given a ...
2k views

### Radar terminology - Specific meaning of “video signal”

In the radar literature, particularly in older references, the term "video signal", "downrange video", or just "video" is used to describe the radar signal at a certain point in the processing chain. ...
2k views

### Radar signal processing - Difference between range gate/range bin

In learning about radar signal processing, I see two different terms that sometimes seem to refer to the same thing, but sometimes different things: Range gate Range bin Usually, I interpret both to ...
201 views

### Help in understanding from book expression of variance of an estimator : PRBS vs real valued input

The question is based on Book : Fundamentals of Statistical Signal Processing by Steven Kay, Chapter 4 : Eq(4.21). The expression for the variance of the estimated coefficients when the input is PRN ...
155 views

### What do certain terms mean in EEG processing describing frequency bands?

I've recently started a project about detecting driver drowsiness with an EEG and came across some terms I didn't quite understood: ...increase in theta activity occur... - ...low voltage theta ...
143 views

### White noise gain of uniform spline interpolation

Uniform spline interpolation is fully defined by its continuous-domain impulse response. I noticed that the integral of the square of the impulse response over its support gives the average ...
7k views

### Is there a technical term for this simple method of smoothing out a signal?

Firstly, I am new to DSP and have no real education in it, but I am developing an audio visualization program and I am representing an FFT array as vertical bars as in a typical frequency spectrum ...
70 views

### Why is the term deconvolution used more for signals and not so much (or at all) for systems?

Wikipedia defines mathematical deconvolution here, and with the examples given and my experience, what I've read over the years is that deconvolution is used to determine an input signal provided a ...
243 views

### What do you call it when you add zeros between the elements of a vector?

What do you call it when you add zeros between the elements of a vector? let's say you have x =[1 2 3 4] and ...
17 views

### How is per-class rate defined?

I've recently read the following For our pixel labeling, consistent with , we report the number of pixels correctly classified (per-pixel rate) and the average of per-class rates. The per-...