41 votes
Accepted

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

What you've implemented is a single-pole lowpass filter, sometimes called a leaky integrator. Your signal has the difference equation: $$ y[n] = 0.8 y[n-1] + 0.2 x[n] $$ where $x[n]$ is the input (...
Jason R's user avatar
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26 votes

What would be an example of something digital which isn't electronic?

Counting with my fingers. Also when I was a kid in the '60s, all of the adding machines and cash registers were digital and mechanical.
robert bristow-johnson's user avatar
21 votes

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

Warning: include some history, old papers (I love them) and punch cards! You used, with $a=0.2$ the form: $$y(n) = y(n–1) + a[x(n) – y(n–1)]\,,$$ sometimes written as: $$y(n) = ax(n) + (1 – a)y(n–1)\,...
Laurent Duval's user avatar
18 votes

Digital circuits are made of analog parts

Counter question: Can you name any circuit, that is NOT made from analog parts? And further, what is a digital part? The basic components of any (integrated) circuit are transistors. While they can be ...
Max's user avatar
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16 votes

What would be an example of something digital which isn't electronic?

A scoreboard flipper (or whatever it's called) immediately came to my mind:
Steve's user avatar
  • 261
11 votes

What would be an example of something digital which isn't electronic?

The difference engine and a number of other pre-electronic mechanical calculators are probably the closest to what we consider nowadays digital. And they are, well, pre-electronic. A mechanical ...
Martin Epsz's user avatar
10 votes

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

Are there better approaches or further study on solutions to this which I should look at? The normal approach for audio meters is a "lossy peak detector". ...
Hilmar's user avatar
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10 votes

Is non-digital necessarily analog?

Please see this answer in the english stackexchange site on the origins of "analog", where it is discussed how the term specific to electronics came to use in the 40's with the emergence of ...
Dan Boschen's user avatar
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10 votes

What would be an example of something digital which isn't electronic?

The word digital literally comes from the Latin "digitus" meaning a finger or toe, which eventually entered English with both literal and figurative uses. By the 14th century, the word "...
Robert Columbia's user avatar
9 votes
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Meaning of Phase response of a filter? In simple words?

There are many good answers here. I will try to take the reverse approach in order to explain in very simple words what is necessary in order to keep the output's shape same as input's, and what ...
DSP Rookie's user avatar
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9 votes
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Is there an adjective describing a filter with kernel that has zero mean?

"Zero-Mean" is the word that's commonly used to describe signals and signals with a zero average. "This is a zero-mean filter." If you really mean a filter that is specifically ...
Marcus Müller's user avatar
9 votes

Meaning of arrow head in dirac delta?

The arrow head is a symbol. It symbolizes "there's a Dirac delta at this position". That's all its meaning. Is it referring that at t=0, amplitude is infinity? Ahhh, no. You cannot say &...
Marcus Müller's user avatar
8 votes
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Is there a name for $f(x) = |x|^n \cdot \operatorname{sgn}(x)$?

There are many instances (eg Handbook of Computational and Numerical Methods in Finance, p. 42, Eq. 2.25) where it is simply called the "signed power" "signed power-$p$ function" or "signed power law"...
Laurent Duval's user avatar
8 votes
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What would be an example of something digital which isn't electronic?

Boolean algebra? That's not electronic, that's pure math and logic. It can just be and commonly is implemented with electronic circuits, but you can just as well make a logical AND gate with ...
Justme's user avatar
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7 votes

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

Around US DoD contractor circles, this particular filter is frequently called an "alpha filter", because it can be characterized with one parameter that is traditionally named "alpha". It is directly ...
John R. Strohm's user avatar
7 votes

What's the difference between the Gabor and Morlet wavelets?

For those looking for a compact description, I found this nice docstring while inspecting the kymatio GitHub repository: A Morlet filter is the sum of a Gabor ...
fr_andres's user avatar
  • 170
7 votes

Is non-digital necessarily analog?

I appreciate this digital data definition: information represented as a string of discrete symbols each of which can take on one of only a finite number of values from some alphabet Although I am ok ...
Laurent Duval's user avatar
7 votes

Digital circuits are made of analog parts

Nothing in the physical world is digital. As far as signals are concerned, digital signals only exist inside a computer (or on a piece of paper perhaps). In order to actually interact with or ...
Hilmar's user avatar
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7 votes

S domain vs frequency domain?

The s domain is synonymous with the "complex frequency domain", where time domain functions are transformed into a complex surface (over the s-plane where it converges, the "Region of ...
Dan Boschen's user avatar
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6 votes
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Why use parametric based estimation methods - confusion regarding terms

Hi: I'll try to answer as briefly as possible and only with respect to statistics. not dsp. In statistics, if you have a nice pdf such as the normal distribution, then maximizing the likelihood is ...
mark leeds's user avatar
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6 votes

What is the meaning of channel capacity?

1) Is there a connection between the modulation kind and the channel capacity? Channel capacity is usually defined as the number of information (usually measured by the number of bits) can be sent ...
AlexTP's user avatar
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6 votes
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What is the meaning of channel capacity?

1) Is there a connection between the modulation kind and the channel capacity? The capacity of a channel indicates the upper limit of how many bits can be transmitted per second over the channel with ...
Jim Clay's user avatar
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6 votes
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What do you call it when you add zeros between the elements of a vector?

In the context of filter banks, simply upsampling (without filtering, or with the trivial all-pass filter, as Wikipedia relates it to interpolation), denoted by an up-arrow, as illustrated below fro a ...
Laurent Duval's user avatar
6 votes

Radar terminology - Specific meaning of "video signal"

You also see this on Spectrum Analyzers; "video bandwidth" for the same reason: the video is the output voltage from the power detector used to drive the vertical on a display (when the horizontal is ...
Dan Boschen's user avatar
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6 votes

Meaning of Phase response of a filter? In simple words?

Here is the same experiment done in my blog: https://poweidsplearningpath.blogspot.com/2020/04/chapter-51-meaning-of-general-linear.html First, there is a tiny mistake in the question. Not all FIR ...
Po-wei Huang's user avatar
6 votes
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What do Signal Processing experts do, in essence?

Signal processing is often at a junction between applied statistics, numerical math, analytic math, physics, electronics and programming. Big data, visualization and machine learning may be ...
Knut Inge's user avatar
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6 votes

Meaning of arrow head in dirac delta?

On the wiki page for the Dirac delta function, you can find one meaning of the arrow. It somehow means that is not "defined" as a constant defined value, but more as a factor applied to ...
Laurent Duval's user avatar
6 votes
Accepted

Number of dimensions? Color image vs gray scale image? Colour video vs gray scale video? Especially in the context of MATLAB

Color images are usually modeled as a vector valued function of 2D: $$ I : \mathbb{R}^{2} \to \mathbb{R}^{3} $$ Namely for 2D coordinates input it outputs 3 values (RGB). Hence images are 2D functions....
Royi's user avatar
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6 votes

Digital circuits are made of analog parts

The diagram below shows the different voltage thresholds for TTL (transistor-transistor logic) logic 0 and logic 1 values. As you can see, the $y$-axis has an analog voltage, and the valid "low&...
Peter K.'s user avatar
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6 votes

Cross-correlation seems defined backwards

Interesting question. For purposes of "pattern matching" the resulting peak of the auto-correlation function will either be consistent with the actual time offset between the matching ...
Dan Boschen's user avatar
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