What is Time domain: Definition and 41 Discussions

Time domain refers to the analysis of mathematical functions, physical signals or time series of economic or environmental data, with respect to time. In the time domain, the signal or function's value is known for all real numbers, for the case of continuous time, or at various separate instants in the case of discrete time. An oscilloscope is a tool commonly used to visualize real-world signals in the time domain. A time-domain graph shows how a signal changes with time, whereas a frequency-domain graph shows how much of the signal lies within each given frequency band over a range of frequencies.

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  1. brotherbobby

    To find the range of a given ##\sin## function

    Attempt : The domain of the function ##\sin(3x^2+1)## is clearly ##x\in (-\infty, +\infty)##. The values of ##x## go into all quadrants where the ##\sin## curve is positive and negative. Hence the range of the function ...
  2. EmmanKR

    Finding the Frequency Domain and Time Domain magnetic field

    I was wondering if anyone could walk me though a better explanation on how to get the given results for these two questions. The solutions posted by my professor aren't really clear to me so if anyone is able to better explain how to get the solution it would be much appreciated!
  3. tworitdash

    Rotating radar time domain data

    I want to simulate the time domain data for a rotating radar. I assume that the space around the radar is filled up with a very big extended object and it moves with a constant speed in one direction. Picture attached.I don't take range information here. I am only concerned about the velocity as...
  4. tworitdash

    MATLAB Creating and recovering a frequency shift in time domain in MATLAB

    I am trying to simulate and process the Doppler signals. My main problem is a little more complex so I am only posting a simple version of it. Task1: I have a time-domain signal with the velocity of the target as mu. I need to change the velocity to mu cos(theta) where theta is a vector from 0...
  5. tworitdash

    MATLAB How to change the frequency values inside a time domain signal phase

    The problem I am having is simple. I have a Gaussian spectrum initially. Like this, Process 1: S = m0/sqrt(2*pi*sigma^2) * exp(-(vel_axis - mu).^2/(2*sigma^2)); Here, mu is the mean velocity (frequency) and sigma is the standard deviation. vel_axis is the axis on which I am calculating this...
  6. M

    Trouble Understanding Phasor to Time Domain Conversion Math

    This is a problem about converting from the phasor to time domain. I am having trouble following the math that the textbook is doing. I was thinking the final answer should be: i(d, t) = 0.20 cos(ωt + βd + 159◦) - 0.091 cos(ωt − βd + 185.6◦) emphasize the minus 0.091 instead of plus 0.091 as...
  7. S

    [AC Circuit] How do we convert from the time domain to the phasor domain?

    In this example, We need to covert e2 & e5 to a form with imaginary number . we will obtain e2=j10 & e5=20 Can anyone explain how we got this?
  8. V

    Python Phase shifting a measured signal directly in time domain

    I need to perform a phase shift for a measured time domain signal. The signal consists of around 1000 points. I wrote an algorithm for this in Python a while ago and it seems to work as intended, but now I noticed that the algorithm is actually unexpectedly slow. Is it so that phase shifting is...
  9. Behrouz

    A Finding a specific amplitude-frequency in the time domain

    Hello, I have a signal and got the FFT result of that. I have shown them both below along with the MATLAB code. May I ask if there is any method to find the time zone(s) in the signal that a specific frequency has(have) happened? The reason I'm asking this is that I want to specify the time...
  10. C

    Solving a 2D PDE using the Fourier Transform

    Homework Statement Solve the following partial differential equation , using Fourier Transform: Given the following: And a initial condition: Homework EquationsThe Attempt at a Solution First , i associate spectral variables to the x and t variables: ## k ## is the spectral variable...
  11. D

    Question regarding Fourier Transform duality

    Homework Statement Given the Fourier transformation pair ##f(t) \implies F(jw)## where ##f(t) = e^{-|t|}## and ##F(jw)=\frac{2}{w^2+1}## find and make a graph of the Fourier transform of the following functions: a) ##g(t)=\frac{2}{t^2+1}## b) ##h(t) = \frac{2}{t^2+1}\cos (w_ot)## Homework...
  12. C

    Converting phasor to time domain

    Homework Statement Homework EquationsThe Attempt at a Solution I am extremely confused. Everywhere I go to look on how to convert phasors into time domain I get a different answer. I am trying to convert -j to the time domain. My notes says to find the Im(phasor). I have explained in the...
  13. C

    Converting phasor back into time domain

    Homework Statement Find Amplitude of Steady-state voltage across capacitor Homework EquationsThe Attempt at a Solution I'm at the very last step of changing it back into the time domain to obtain my ampltiude. I was planning on getting it into the form a + bj, then using trigonometry and...
  14. MexChemE

    I Motivation for Fourier series/transform

    Hello, PF! I am currently learning Fourier series (and then we'll move on to the Fourier transform) in one of my courses, and I'm having a hard time finding motivation for its uses. Or, in other words, I can't seem to find its usefulness yet. I know one of its uses is to solve the heat...
  15. M

    Help -- Time Domain Power, Volt-Amperes in lagging circuit

    Please find attached a spreadsheet trying to plot an inductive/resistive circuit in the time domain and show instantaneous power and Volt Amperes. Logic tells me power can not go negative, but I am not sure my power plot is correct. Can someone please review the spreadsheet and chart to tell me...
  16. gfd43tg

    Sketching Transfer function in time domain

    Homework Statement $$ y(s) = \frac {s}{(s+1)(2s+1)} u(s) $$ Where ##u(s)## is the step function ##\frac {1}{s}## Find the output at t=0 and t= infinity Homework EquationsThe Attempt at a Solution My question is kind of basic, so I know the final and initial value theorem $$ \lim_{s \to 0}...
  17. SSGD

    Industrial Event Takt Times (production cycle times) and Probability

    Background: I am a Mechanical Engineer working as an Industrial Engineer. I have collected some data that is the amount of time that an event took to complete. I first assumed it would be normally distributed, but after plotting a histogram and a normal distribution with the data, I doubt...
  18. J

    Time Domain (Oscilloscope) View of a Photon or Light Wave

    We can view the amplitude vs time variation of an EM wave using an oscilloscope with the needed bandwidth. Such a view shows us the shape of the wave (sinusoid or other), the number of cycles contained in a given burst, any modulating signal etc. Though it wouldn't be measured with an...
  19. gfd43tg

    AC Op-Amp output voltage expression in time domain

    Homework Statement For vi(t) =V0 cosωt, obtain an expression for vout(t) in the circuit below and then evaluate it for V0 = 4 V, ω = 400 rad/s, R = 5 kΩ, and C = 2.5 μF. Homework Equations The Attempt at a Solution For this problem, I am having difficulty taking that second term...
  20. D

    MHB Understanding the First Order Prototype Solution in Time Domain

    Consider the first order prototype, \[ \frac{dy(t)}{dt} + \frac{1}{\tau}y(t) = f(t),\] driven by a step function, \[ f(t) =...
  21. C

    DSP, going from freq domain to time domain

    Homework Statement X(w) = 3cos(2w) + 2 sin(3w) calculate x(n) Homework Equations x(n) = (1/2pi) ∫ X(w) e^(jwn)dw The Attempt at a Solution When integrating over 0 to 2 pi, my answer is 0. Which would not be the case.
  22. K

    Natural frequency from time domain and frequency domain plot

    Anyone have an idea to find a first and second natural frequency from time domain and frequency domain plot resulting from an accelerometer measuring the vibration in cantilever beam ? Thanks very much :)
  23. D

    Time domain noise from spectral density

    Hello. Say I have a given noise spectral density and I want to plot the random noise signal arising from this spectral density in the time domain. How can I generally accomplish this? For white noise, I would just pull numbers from a normal distribution, but I don't know what to do for non-white...
  24. M

    What is time domain aliasing in linear convolution?

    please anyone can help me to get the answer?I have idea about aliasing which is basically in frequency domain caused by lower sampling rate which does not satisfy the Nyquist criteria. Frequency aliasing refers to higher frequency getting the image of lower frequency.But what is time domain...
  25. H

    Understanding Cutoff Frequency & Time Domain: Help Needed

    Hi, I am trying to understand the impact of cut off frequency on the gain and trying to relate it in time domain but unable to do so. For e.g., I have built a single pole RC filter wherein R and C values are chosen to match the cut off frequency of 1K (R = 10KΩ/C = 16nF). The input is a square...
  26. K

    Constructive Interference Problem in the Time Domain

    Homework Statement Two waves on a string are given by the following functions: Y1 (x,t) = 4cos(20t-x) Y2 (x,t) = -4cos(20t+x) where x is in centimeters. The waves are said to interfere constructively when their superposition |Ys| = |Y1 + Y2| is a maximum and they interfere destructively when...
  27. M

    Tension on a capacitor from Laplace domain to time domain.

    The problem ask me to find the tension on a capacitor after a switch has been opened. I have everything in terms of equations in s-domain and I'm sure they aren't wrong because I checked on the book. My unique problem is to understand a certain passage necessary to find the voltage knowing...
  28. K

    Multi resolution Time Domain (MRTD)

    Hi everybody, i am having difficulties to write a program using only MATLAB to solve the Mrtd SCHEME...that is solving the maxwell equations...can anyone please help me
  29. D

    Windowing in Frequency Domain: Exploring Effects on Time Domain Data

    Hey @ all, when windowing in DSP in time domain one multiplies all recorded time samples with a weighting factor (hanning, hamming, etc.), followed by a Fourier transform (FFT) to reduce sidelobes in the spectral domain. But now when thinking about starting up in frequency domain where I...
  30. A

    Getting time domain current from impedance and voltage measurement?

    I'm working on a high power multi-phase DC/DC converter where the load current has some fast transients. We can easily measure the output voltage in the time domain, and also measure the power distribution network impedance in the frequency domain. So, I think I would try converting the...
  31. A

    Boundary conditions and time domain electromagnetic waves

    Boundary conditions & time domain electromagnetic waves: does classical model fit? Consider two propagating media: a lossy dielectric medium and a lossless dielectric medium. Thus, the interface that separates them has two tangential components of electric field, one for each medium. One of...
  32. H

    How would wavefrom change change in time domain, frequency domain and

    how would wavefrom change change in time domain, frequency domain and its rms value if a dc level of 1 volt was added.
  33. S

    Fatigue analysis:frequency domain vs time domain

    I have read a lot of paper about fatigue damage, in some fields it is particularly used the time domain approach while in others the frequency domain approach, but I haven't understood when it is better to use frequency approach respect time domain approach. May you help me to understand better...
  34. C

    Convert Time Domain to Phasor Domain with Euler's Formula

    how is euler's formula useful? it must have something to do with converting from the time domain to the phasor domain and back, but i can do that without euler's formula
  35. R

    Transient (Time domain) in transmission lines

    Hello. I am watching this video: https://www.youtube.com/watch?v=xIQtnQ9XPbE and he says there: I see that the wave turns into a "normal" sinus in the end, but it's not constant. I think, that even on an unmatched transmission line, the waves should go back and forth, but eventually...
  36. A

    Engineering RLC circuit step response time domain

    This is more of a math question but i feel like i will get more help among Electrical Engineers. I successfully found the step response of an RC circuit in the time domain using Laplace Transforms. But i can't seem to figure out how to do it with an RLC transfer function. I have the following...
  37. F

    !AC Generator Current: Mathematical Expression in Time Domain

    Consider a simple alternating current generator such as Hippolyte Pixii's dynamo. The current generated by such dynamo can be described as simple oscillating cosine signal. Assuming for simplicity that the max current generated each time a pole of Pixii's magnet passed the coil is (2/pi)0.5...
  38. C

    Time Domain Functions to Frequency Domain

    How do you convert functions from the time domain, to the frequency domain For example: cos(250t + 30degrees) is what in the frequency domain? Are there some general steps I can follow to do this?
  39. A

    How Do You Convert 's' Constants to 't' Using Inverse Laplace Transforms?

    i have a question about laplace transforms. I had to find the maximum of a three exponential equation f(t). What I have done is took the first derivative of f(t) and equated it to zero. Now f'(t) is also a three exponential equation ( like f'(t)= e^at +e^bt +e^ct). So I have taken laplace...
  40. A

    How Can I Convert a Constant s Value to t in Laplace Transforms?

    Homework Statement i have a question about laplace transforms. I had to find the maximum of a three exponential equation f(t). What I have done is took the first derivative of f(t) and equated it to zero. Now f'(t) is also a three exponential equation ( like f'(t)= e^at +e^bt +e^ct). So I...
  41. K

    Find Time Domain Expression for Electric Field e(r,t) of Uniform Plane Wave

    1. Problem Statement Write time-domain expression for electric field e(r,t) of unifrom plane wave with amplitude Eo and frequency f= 1 GHz propagating in free space. The plane wave is propagating in yz plane, 30 degrees from the +y-axis, and 60 degress from -z axis. It is linearly polarized...