All Questions
Tagged with signal-processing waves
59
questions
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10
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Phase Slope Distance Calcuation
After trying to implement IFFT algorithms for phase-based ranging, as outlined in this very interesting and descriptive blog post; I've been getting horrendous results (orders of magnitude inaccurate),...
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2
answers
151
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Weird looking sine wave behavior in an electric circuit
while studying an RLC circuit I noticed some weird like sine waves at low frequencies (1-9 kHertz) on the inductor,
The amplitude behavior did not follow the theoretical model. Instead, suggested the ...
- 31
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1
answer
33
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What relationship between the time recording length and the frequency bandwidth?
In model testing for ocean waves, the data recording duration is usually longer the better especially for irregular waves. The recording length shall be long enough to achieve sufficiently small ...
- 138
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2
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84
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I don't understand intuitively why the instantaneous frequency is obtained by calculating the time derivative of the phase
I don't understand intuitively why the instantaneous frequency is obtained by calculating the time derivative of the phase
- 11
1
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1
answer
54
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How to justify sound propagation is a linear time-invariant (LTI) system?
Background
A linear time-invariant (LTI) system (black box) is one described by the system:
\begin{align}
\dot{\xi}(t) & = A\xi(t) + B\omega(t), \; \xi(0) = 0 \label{eq-abc-1}\\
\lambda(t)...
- 151
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27
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Comparison between wave equation theory and transfer function theory
I deal with analysis of acoustic signals in solids. And after some literature research in physics and mathematic, I have a question about the followings two theories:
Wave equation theory: Imagine I ...
1
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2
answers
47
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Is it possible to, like white noise, excite all audio frequencies equally, but with a more immediate & less random burst? Like a signal discontinuity?
I am trying to generate an audio signal that, like white noise, has "equal intensity at different frequencies, giving it a constant power spectral density", but unlike white noise, can be ...
- 321
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21
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FWHM and Beam Width of transmitted beam of ultrasonic (ultrasound) transducer
Im a studying ultrasonic transducer and I got a question about FWHM and Beam Width while solving some problems.
In the lecture, I learned that Beam width is calculated by:
$2\Delta\theta = \frac{3.8\...
- 43
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25
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Two-Ray Ground-Reflection Model: Understanding the Difference in Phase Offsets at the Receiver
Currently, I'm trying to understand the Two-Ray Ground-Reflection Model.
During my research, I came across the following simplification expressing the received power as follows (taken from Wikipedia):
...
- 11
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0
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24
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Is the strongest acoustic signal always the closest?
I have a single beam echosounder that I use to measure the distance to an object underwater. It emits an acoustic pulse and listens to the reflections. Using the time of flight and the strongest ...
- 1
22
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12
answers
8k
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How do computers store sound waves just by sampling the amplitude of a wave and not the frequency?
All of this just doesn’t make sense though.
I mean, doesn’t the amplitude represent the loudness and the frequency the pitch? Aren’t they completely independent from each other?
Is the book just ...
- 390
7
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2
answers
1k
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Why does superposing an infinite number of waves of different wavenumbers eliminate periodicity and may sometimes result in a localised wave?
I am studying how wave packets are defined in quantum mechanics, but I am finding it hard to intuitively understand why superposing an infinite number of waves of different wavenumbers $k$ may ...
- 390
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1
answer
58
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Can multi-instrumental sound be reconstructed from a waveform?
This question came about when I saw someone wearing clothing with a waveform on it. I wondered if it would be possible to reconstruct the original sound from the printed waveform.
I understand that a ...
- 101
7
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2
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561
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What do I hear when listening to a computer-generated sine wave?
When I use a sine-wave generator (such as this one), I give credit to the software and my hardware that a pure sine wave is produced (as close as is technologically possible) — that is, no harmonics. ...
- 173
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2
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47
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How to convert from a wave-reading?
I have a series of wave-readings which show wave amplitudes pr. time unit for different events. So on the $x $-axis we have seconds, and on the $y$-axis, wave height.
If I want to convert this to a ...
- 143
1
vote
2
answers
85
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Signal Processing – Discrete Fourier Transform and Incomplete Fourier Series
I'm working on a paper where I'm collecting sound pressure data from a chord's wave and trying to create a frequency spectrum to find the individual frequencies that make up the chord.
However, I can'...
- 13
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1
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1k
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Understanding Upper Side Band (USB) and Lower Side Band (LSB) of Modulated signal
I want to know that what is UPPER SIDE BAND and LOWER SIDE BAND in this picture?
I have a confusion that the portion above the x axis is the USB and the portion below the x axis is LSB. I have doubt ...
1
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1
answer
53
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Wavelength and frequency associated with a wave pulse
What are the definitions of wave length and frequency of a wave pulse?
- 468
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1
answer
127
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What would happen when two wave functions intersect in a Fourier series representation of periodic signals? [closed]
I saw a piece of code on github which transforms the planetary movement into the fourier wave function.
These circles are given by the x and y ordinates: x=cos(ωt) y=sin(ωt), which are periodic. ...
- 109
2
votes
1
answer
171
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Fourier transform of an exponentially decaying waveform
Consider an atom oscillating at a certain frequency. The amplitude of the oscillation decreases over time such that the waveform can be modeled by an exponential function, but the frequency remains ...
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1
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1
answer
47
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Signal Generated from Transmitter [closed]
Suppose that we have a transmitter of $150.100\ \mathrm{ MHz}$.
We also have a receiver at a fixed point.
The transmitter constantly generates signals toward the direction of the receiver.
Based only ...
- 115
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1
answer
49
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Infer 3D location (Height, Latitude, Longitude) based on Signal Strength
Sorry if my question is irrelevant.
Let's consider two cases:
$1)$ Suppose that we have an Antenna and a tagged individual that can be pinged from the Antenna. Suppose that the individual is pinged ...
- 115
5
votes
2
answers
808
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Rope as Communication Media [closed]
I'm a computer student that used to play microcontroller and sensor. I'm not sure whether this topic fits on this site.
I'm thinking about using rope as media communication instead of fiber optic. I ...
3
votes
1
answer
130
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Analog Is Digital (Discrete)?
As I started reading a bit about analog vs digital signals, I keep returning to this thought. This could be something pretty obvious to the pros out there, but is it safe to assume that underneath it ...
- 131
5
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2
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963
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What, mathematically, is the power spectrum of a signal?
Given a signal $f(t)$ defined on $t\in(-\infty,\infty),$ what is the precise definition of the power spectrum of $f$, i.e., what is the mathematical operation that takes $f$ to the output of an ideal ...
- 3,407
1
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1
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96
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Can we decompose sound like white light is decomposed (dispersed) in different colors?
When we send white light through a prism, the light is decomposed in the colors that constitute it due to the different velocities which different frequencies. Is there a way to decompose "white ...
1
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0
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35
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Can a signal calculate its time period?
I wanted to know if a radio wave has some kind of data for example a kind of packet information (if its a thing) and it gets transmitted and gets received by a receiver, then can it calculate the time ...
- 21
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1
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170
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Does phase of a signal (very low frequency, 0-100Hz) change due to pink noise?
One might experience pink noise when dealing with low frequency signals (0-100Hz). Curious to know whether pink noise has an effect on phase of the signal specially in lowest frequencies 0-10Hz.
- 235
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3
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157
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How does a spectrum analyzer works. Example with particular case: eyes [closed]
[edit]: I reformulated my question to first talk about general spectrum analyzer and then ask about how vision works (which is a particular case of spectrum analyzer as I explain below).
Let's assume ...
- 1,450
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4
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481
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Why exponential terms like $\exp (i\omega t)$ make no contribution when averaged over a long time?
In the physics of waves, I often see expressions like
$$A\exp(i\omega t) + f(t)$$
where $A$ is a constant, $w$ is the angular frequency and $f(t)$ is an arbitrary function that depends on time.
It ...
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