Questions tagged [signal-processing]
The subfield of electrical engineering that focusses on analysing, modifying, and synthesizing signals such as sound, images, and scientific measurements.
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Confusion with spectral density of the emitted power of blackbody radiation
I'm reading a book discussing electrons' velocity fluctuations, which would cause electronic noise when detecting signals.
Velocity fluctuations originate from thermal motion. Superimposed on the ...
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Data transmission via laser illuminating the ceiling
I've heard a data transmission technique proposed more than once wherein a base station would fire a laser at the ceiling of an indoor space. The pulsing of this laser would be observed by one or more ...
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Evaluate action of $f(\frac{d}{dx})$ using the Fourier/Laplace transform
Initially I asked this question on mathoverflow. I however thought physicists may face this sort of problem more than mathematicians (I am an engineer). Due to that, I decided to ask here as well.
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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 ...
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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?
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Sensor Array Position Calibration in Anisotropic Media
Problem.
I have a sensor array consisting of $n \gg 4$ receivers at unknown locations $\langle x_n, y_n, z_n\rangle$ embedded in an anisotropic medium whose index of refraction varies as a known ...
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Maximum bitrate density of a shared medium
I'm not a physicist, so my apologies if this isn't worded correctly, or if it even is a valid question.
I was recently learning how WiFi works and how the slowest devices on a channel can slow down ...
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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. ...
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How do I convert the Amplitude from Power/Amplitude spectral density?
I've started working on PSD for seismic signals. In theory, PSD signal can be expressed in 2 ways. One in $(PSD=g^2/Hz)$ and other in $PSD=((meter/second^2)^2/Hz)$ and also ASD=(√PSD). Here $g$ is the ...
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Can we quantify the pitch of a sound that is a mixture of many frequencies?
How is the pitch of a sound defined quantitatively when it is a mixture of many frequencies? For example, the sound emitted by a plucked guitar string, or say, the pitch of somebody's (normal) voice. ...
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Is this a good use of the convolution?
I would like to replicate the real response of an instrument to some signal. Here's what I have in mind: I generate some ideal signal. I then add Gaussian noise to it to produce a realistic signal s(t)...
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An idea to retrive phase of different frequency from noisy experimental data
There is a lot of idea in this website to retrive phase of certain frequency from a noisy oscillation. For example this one: use band pass filter to filter out certain frequency and then use hilbert ...
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Pulse Area Uncertainty for a given Sample Rate and Bit Resolution
I'm recording pulses and want to approximately know how precise I can measure this with my Oscilloscope. I'm recording with 15 bit vertical resolution -> 1/(2^15) and a sample rate of 125 MS/s ->...
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Why the General Lomb-Scargle results are doubled?
I got a problem when computing the GLS on MATLAB for my master deegree thesis.
I need to do a comparison between the PSD and amplitude spectrum of a signal computed with three different metods, the ...
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What is the difference between radar cross section and intensity/amplitude?
I've been tasked with simulating a radar system, and I think I understand the problem, except I'm supposed to be providing the outputs in both radar cross section and amplitude.
What's the difference? ...
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Applications of Signal and System theory [closed]
I recently heard a lecture about Signals and Systems and find the subject extremely exciting. I would like to do more in this direction, so I would be interested to know in which modern research area ...
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Understanding the Fourier transform of a signal already with amplitude and phase information
I'm from an image processing background and am working my way into optics. I'm working on phase retrieval problems, trying to understand the Gerchberg-Saxton algorithm. I found this video which is ...
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How can we show that a lens is a low pass filter?
I understand from the derivation in Goodman Chapter 6 that a lens Fourier transforms light from the front focal plane onto the back focal plane, ignoring aperture effects. I've also read that a lens ...
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Physical interpretation of FFT frequencies
I need to calculate the PSD of a discrete signal and want to compare it to other processes. By Nyquist theorem, I only can account half of the frequencies.
Assume I have a signal of length $N=100$, ...
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Data transmission through optical fiber and copper wire
I read the following in one reference: A copper wire (twisted pair), the link traditionally associated with low bit rate transmission, is still in use in the modern data centers transmitting data at ...
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Velocity from acceleration equation
I've been working with an accelerometer, and was assigned the job of trying to find the velocity from the accelerometer, I take acceleration data every 10 ms (sampling rate 100KHz) and I used the ...
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Converting PSD against spatial frequency to RMS against temporal frequency
I am putting together some simple ride comfort models that use road surface PSDs from ISO 8606 (road surface profiles) as inputs to a quarter car suspension model to produce body acceleration spectra. ...
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What happens during under-modulation?
I need clarification regarding what exactly happens to the information in amplitude modulation if it is under-modulated. I know that if it is over-modulated, some information will not reach the ...
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How to find peak power at 1550nm using an optical meter?
I have a setup of tunable laser source at 1550nm connected to a spectrometer(Can't publish the name of spectrometer). The spectrometer has a range of 1510-1595 nm. The graph shows wavelength vs ...
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Is there any known result about the "average period" of a complicated oscillating function?
Say we have some frequency spectrum, $f(\omega)$, where
$$
f(t) = \frac{1}{2\pi} \int_{-\infty}^\infty d\omega \; f(\omega)e^{-i\omega t},
$$
and we know that $f(t)$ is some sort of ...
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Difference Between a Time-Domain and a Simulation Domain Acoustic Pressure Simulation
I would appreciate it if someone would be able to clarify my doubts. I'm currently working on acoustic simulations in COMSOL and is currently confused on the information provided by the simulations ...
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Phase difference of two time series
Consider we have two time series and for each of them , we know the phase (Phase1 and Phase2). We want to compute phase difference between these two time series. We define the phase difference as (...
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What is meant by 2D fourier transform of an image?
I have some questions about this interesting concept I came across about 2D Fourier transform, please...
Firstly, the Fourier transform of a 1D signal (such as a sound recording) is as follows:
The ...
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During a wheelie, is there a braking effect on the back wheel of the scooter that is triggered physically when the bike is close to vertical?
When someone does a wheelie using a motorcycle (scooter), it looks to me like something is stopping the the motorcycle from tipping over backwards so far that it crashes. Is there some sort of (built ...
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Is the human singing voice different from a linear, time-invariant (LTI) system?
Typically the human voice is modelled by a linear, time-invariant (LTI) system.
An LTI system cannot add any frequency components to an input signal. This is obvious from the input-output relation in ...
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