What is Waveform: Definition and 129 Discussions

In electronics, acoustics, and related fields, the waveform of a signal is the shape of its graph as a function of time, independent of its time and magnitude scales and of any displacement in time.In electronics, the term is usually applied to periodically varying voltages, currents, or electromagnetic fields. In acoustics, it is usually applied to steady periodic sounds—variations of pressure in air or other media. In these cases, the waveform is an attribute that is independent of the frequency, amplitude, or phase shift of the signal. The term can also be used for non-periodic signals, like chirps and pulses.
The waveform of an electrical signal can be visualized in an oscilloscope or any other device that can capture and plot its value at various times, with a suitable scales in the time and value axes. The electrocardiograph is a medical device to record the waveform of the electric signals that are associated with the beating of the heart; that waveform has important diagnostic value. Waveform generators, that can output a periodic voltage or current with one of several waveforms, are a common tool in electronics laboratories and workshops.
The waveform of a steady periodic sound affects its timbre. Synthesizers and modern keyboards can generate sounds with many complicated waveforms.

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  1. S

    Location of point mass based on graphs

    Since figure (a) shows the waveform at t = 1 s, I also look at figure (b) when t = 1 s. The value of y is zero so I try to find the location of x from figure (a) for which y = 0. There are two value of x, 0 and 2 m. Let say x = 0 is point P and x = 2 m is point Q. The period is 4 s so at t = 1...
  2. K

    Can a Square Wave Tachometer Drive be Powered by a Sine Waveform?

    I'm a marine engine mechanic, and as engine controls & sensor systems have gotten more complicated with current technology, my shop gets more & more requests for instrumentation & control system repairs. I have a lot of trouble getting technical info from suppliers, so I have been starting to...
  3. ergospherical

    A What is the Expression for the Waveform of an In-Spiralling Compact Binary?

    This paper gives the following expression for the waveform from an in-spiralling compact binary:\begin{align*} h(t;\boldsymbol{\theta}) = \frac{1}{r} Q(\boldsymbol{\phi}) \mathcal{M}(\pi \mathcal{M} F)^{2/3} \cos \Phi(t) \end{align*}where ##\boldsymbol{\phi} = (\theta, \varphi, \psi, \iota)##...
  4. Benjamin_harsh

    What does the RF waveform of wifi/bluetooth look like?

    Homework Statement:: I tried google search and I give up. Relevant Equations:: How does output wave of wifi/bluetooth look like? How does output wave of wifi/bluetooth look like?
  5. A

    Understanding CPU Frequency Waveforms and Dead Time in Modern Processors

    There was a thread recently in another subforums where a user talked about creating "square waves" at Ghz frequencies. It was said there that at that frequency range one cannot have a square wave as the inductance "rounds off" the edges making the waveform sine like. I am wondering then how...
  6. S

    Graph of waveform across diode shown by CRO

    Option (A) and (B) is wrong because the waveform should be half-wave, not full-wave. But how to know whether it will be (C) or (D) based on the circuit given? Thanks
  7. Callum Plunkett

    Inverting Op-amp signals and Sawtooth waveform generation

    I’ve been asked to create a sawtooth wave form with four input voltages. After doing this I then added a second op-amp to both change the range of the wave form from -/+5v to -/+2.5 and DC offset of 2.5v to create a wave form that ranges from 0v – 5v as required by the question. For the most...
  8. B

    Waveform of Classic Electromagnetic Induction

    Hi guys, Can someone please provide graphical representation (waveform) of emf induced in coil due to a bar magnet spinning perpendicular to axis of coil. Thanks, SB
  9. H

    I Waveform collapse due to entaglement cascade

    In my limited understanding of the quantum measurement problem, I am imagining the whole thing as corresponding to a kind of "weighting down" by a cascade of entaglement. Here is my very simple understanding of the quantum measurement problem: A waveform (Schrödinger equation) describes the...
  10. E

    Waveform produced by a collapsing magnetic field

    A thought experiment: A electron is moving in a straight line at velocity v. It instantly stops dead. It doesn't move another femtometer. Obviously its magnetic field collapses and produces light. What is the waveform of the light produced? Is it something like this...
  11. cnh1995

    Engineering Single Phase Inverter Waveform

    The answer given is d). Seeing the problem statement, it can be concluded that the load has some inductance, and when the switches S1, S2, S3 and S4 are off, conduction takes place through the anti-parallel body diodes (freewheeling action). Seeing the triggering pulse waveforms, S1-S4 ON...
  12. P

    Engineering Black-box design to create sawtooth waveform

    Hi I received some great help yesterday and i was hoping someone would be able to help me out again today Note: the given equation is very long and would look very messy without being typed in the correct format so I didn't enter the entire thing in the relevant equations box; instead it is...
  13. J

    Engineering Understanding the output waveform and using LTSpice

    For the following circuit I need to find the output waveform. A. Conceptually I am at sea here but I will have a stab at it. My though process is as follows : At a given instant, the AC voltage is at a fixed value and this value drops (##V_drop##) across the resistor ##R##. The voltage...
  14. F

    Generate a triangular waveform using Multisim/MATLAB

    Using any Electrical Engineering software: I tried to solve this question using Multisim. Here's my attempt: That's what I got : Kindly,could someone tell me where is my mistake ?
  15. J

    Engineering Combining these two AC waveforms

    I have calculated V3 to be 294.62sin(1800 pi t + -0.56)V I am confident this is correct but I now need to work out the frequency of the waveform, I believe it may be 900 but I am not too sure if my calculations are correct and I can't find anywhere on line that aids me in this particular instance.
  16. K

    I Using AI for Gravitational Wave Generation

    Hello! Can someone point me towards some papers that use AI for gravitational wave generation? I found many papers using AI to analyze data, but not really something where AI is used to actually generate waveforms. For example this was done for particle physics simulations to increase the speed...
  17. J

    Generating a rising staircase waveform using an integrator?

    Summary:: My understanding of integrators and the waveforms they generate is hazy. The question I am trying to solve is : Sketch the output waveform for an inverting integrator if the input signal is a square wave with amplitude 5 V and frequency 1kHz where the product of Resistance and...
  18. A

    Help with waveform control: frequency, phase and amplitude

    Hello, I am looking for a controller whether programmable or otherwise that could function as a drive and control circuit which would monitor a transformer output connected to a load and then drive an amplifier with a signal that is proportional to the needed one in order to control the output...
  19. J

    Engineering Output waveform after input rising edge and before output falling edge

    A is given waveform, we have to use circuits to get B and C waveform. For B we can use an And Gate with 2 inputs, X and Y. X is buffered (to get some delay) and is fed to Y input of And Gate. So we'll get waveform B. But I don't know how to get C waveform. The question is that even if I extend...
  20. T

    Understanding Waveform & Autocorrelation in Pulse Lasers

    So, I was working on autocorrelation for my pulse laser system and I started to wonder what is the difference between single wave with 400nm of wavelength and two 800nm waves overlapped. In the knowledge, I know of, is that wavelength is the length between two picks. And when it is pulse laser...
  21. Machine1701

    I Why doesn't decoherence apply to unobserved experiments?

    This is based on the Hugh Everetts interpretation of quantum mechanics, where the waveform never collapses but the observer becomes a part of it, thus experiencing decoherence of the wave form from their point of view. So, let's say someone is doing the two-slit experiment. The particles going...
  22. C

    Sketch the waveform to represent the transient response

    Homework Statement Sketch, on a set of common axes, waveforms to represent the transient response of circuits having transfer functions with the following parameters: a) ζ = 0.5, ω = 1×10^3 rad s^-1 b) ζ = 0.2, ω = 2×10^3 rad s^-1 c) ζ = 2, ω = 1×10^3 rad s^-1 Homework Equations wd=wo√(1-ζ^2)...
  23. N

    I How can I amplify and shift the phases of a complex waveform in MATLAB?

    I have a complex waveform in MATLAB that is of the form y = A1 ei * 2 * π * f * t + Φ I need to amplify each sample point of the waveform to an amplitude A2 and also for it to shift phase by φ. I therefore construct a complex waveform for amplification y = (A2 / A1 ) ei+φ Then with...
  24. SemM

    A Non-selfadjointness and solutions

    Hi, I have the two operators: \begin{equation} Q = i\hbar \frac{d}{dx} - \gamma \end{equation}\begin{equation} Q' = -i\hbar \frac{d}{dx} - \gamma \end{equation} where ##\gamma## is a constant. Both of these are not self-adjoint, as they do not follow the condition: \begin{equation}...
  25. F

    I Function describing a moving waveform

    Hello Forum, I am first wondering about the possibility to factor a function ##f(x,t)## into a product of two functions, i.e. ##g(x) p(t)##. Is there any general rule that tells us if this decomposition is possible based on the characteristics of the function ##f(x,t)##? If a function...
  26. T

    Understanding current measurement on an irregular waveform

    I hoped to use a Keithley 2400 source meter to generate a ~120Hz AC signal by outputting a 2-point sweep from 1A to -1A on an infinite trigger. The waveform image is attached below. The end goal is a resistance measurement for bulk semiconductor materials, we prefer AC measurement to avoid...
  27. G

    Why output waveform look like this in bridge rectifier

    in our laboratory class we made a simple bridge rectifier circuit like this then we replaced D1 and D2 with resistors, and when we connected the probes of the oscilliscope on the load resistor it showed a DC output something like this(sorry for the bad drawing) can you guys explain why it...
  28. A

    Actuating Pencil To Draw Waveforms

    I am looking to make a pencil whose tip moves to create a waveform as you move it across the paper.In essence, I want to be able to record a sound and then play the sound through the pencil whilst I draw with it, of course, I will use software to lower the frequency to make it more of a waveform...
  29. J

    Engineering AC Circuit Voltage Waveform Analysis

    Homework Statement An A.C. voltage, V, comprises a fundamental voltage of 100V rms at a frequency of 120 Hz, a 3rd harmonic which is 20% of the fundamental, a 5th harmonic which is 10% of the fundamental and at a phase angle of 1.2 radians lagging. (i) Write down an expression for the...
  30. Noaha

    Why armature MMF is triangular in waveform?

    Why armature mmf is triangular in waveform? According to Faraday's law, the mmf should be rectangular. But I read some where that the total mmf of all the coils sums up to produce triangular waveform. I don't understand how that happen.
  31. JAA

    An elementary question - Percussive waveform moving through human tissue

    I need a better understanding and explanation of how a percussion wave form can move through biological soft tissue. I know that human soft tissue functions microscopically in a fluid environment however I also understand that there are also obstructive forces in the way of a wave moving in a...
  32. H

    B Why does waveform exp[iwt] have negative kinetic energy?

    Why so? Quoted from Quantum Physics 3rd ed. by Stephen Gasiorowicz, p. 26. It was explaining why we ignore the terms with exp[iwt] when adding plane waves to form a wave packet:
  33. D

    Harmonic Distortion in a current waveform

    Homework Statement [/B] Estimate the total harmonic distortion [THD] present in the current waveform using the formula: Homework Equations ##THD\left(I\right)=\frac{1}{I1}\sqrt{\sum_{n=2}^\max\left(In\right)^2}\times 100\%## The Attempt at a Solution I have attached a worksheet for this. The...
  34. A

    Explicit dynamics (LS-DYNA export) -- How to export a Time waveform?

    I am doing guided wave simulation in ANSYS workbench. I applied a load (tone-burst signal) on the model and I ran the simulation successfully. Now, I want to extract the time waveform. Does anybody have any idea?
  35. J

    I What is the Waveform of Virtual Photons?

    My understanding is that the wavelength or frequency of an individual photon cannot be reliably measured. For example, if a beam of monochromatic light is filtered so that only one photon at a time enters a spectroscope, each photon may land anywhere on the screen. Only when a statistically...
  36. H

    I What causes alternator waveform shape?

    I have a permanent magnet alternator. It does not produce a sine wave output, but rather a sort of distorted triangle wave. I did a frequency analysis on it and it showed a series of harmonics. The strongest was the third, with each odd harmonic getting progressively less powerful. It also...
  37. J

    Understanding Comparator and Window Comparator Functionality in Op-Amps

    Hi, While studying opamps I came across comparator and window comparator. I had trouble understanding case of Vin > 2/3 Vcc. As per waveform, comparator 1 is functional and o/p goes negative. But isn't now Vin also more than 1/3 Vcc, so shouldn't comparator 2 make o/p positive. Also when Vin...
  38. E

    Engineering How to analyze diode circuits? (Find waveform generated)

    Homework Statement To analyze these circuits, we need to draw the current path right? I know that current can only flow one direction through a diode. http://i.imgur.com/kipBcax.pngHomework Equations N/A The Attempt at a Solution Are these paths correct? Green = positive, red = negative 1...
  39. cnh1995

    Sampling an ac waveform on microcontroller

    I did a small project on ac power measurement using arduino a few months ago. But it was specifically for 50Hz supply only. I sampled the waveform in a 20ms interval and applied DFT to get the amplitude and phase. This works good when the frequency is between 49.5 Hz to 50.5 Hz. The aim was to...
  40. K

    What Does a Shifted Voltage Waveform Indicate About Load Characteristics?

    https://files.slack.com/files-pri/T0GNF95E2-F0TV5JSSG/voltage_reversed_and_shifted.png This the voltage waveform across a resistor load (15W). The applied voltage is 230V AC at 50Hz. What can be inferred from this? [ the Analog to Digital conversion of Voltage happens at around 1690 Samples per...
  41. Marcin H

    Finding Average Values in a Waveform: Understanding the Concept and Calculation

    Homework Statement Circle all that are correct Homework Equations V(t)=Vocos(wt) The Attempt at a Solution I don't really understand what the question wants when they ask for an average value. Average value of what? And how do you find it. There are a lot of questions with graphs like this...
  42. B

    Creating a Focused Waveform to Pass Through Clothing and Structures

    so I am hatching an idea for a system of equipment which requires a focussed wavelength which will not greatly widen over distances of less than a mile. Also the waveform needs to be sensible by receiver antenna or something of a similar nature. It is necessary that the waveform be able to...
  43. S

    Math expression for a developing waveform?

    Hi all! I have a question about representing waves mathematically. I hope it will make sense. The waves I've been learning about are of the form F(x-vt), which represents a wave-form, every point of which is translated spatially with velocity v. I am wondering if there is a way to...
  44. B

    3 phase bridge uncontrolled rectifier, resultant waveform

    Hi all, Having difficulty understanding the above resultant wave form, been looking at power electronics (C.W.Lander) but don't quite get the addition of the wave forms (positive and negative cycles)can anyone point me to some reading of theory I am missing for this, thanks.
  45. S

    Understanding a sound spectrum analyzer output

    Hi, I am just trying to understand the output of a sound spectrum analyzer. There are three dimensions 1) Time 2) Frequency 3) Volume (db) I am confused about few things here: 1) How should I perceive the volume dimension here? 2) Why are the db values negative here and w.r.t what reference...
  46. E

    Odd (pretty) waveform for third harmonic of violin E-string

    I lightly placed my finger a quarter of the length down the E-string of a violin and drew the bow, forcing the third harmonic. I used an oscilloscope app to look at the waveform. I got this unusually regular pure pattern...
  47. S

    Engineering Waveform of R,L,C in DC circuit

    Homework Statement Draw a time-depended waveform of all components in DC RLC circuit. R=4*1,412 L=1,6 mH C=0,2 mF Udc=15 V Homework EquationsThe Attempt at a Solution DoCircuit simulator I am a bit confussed with this homework because I am aware that capacitor do not conduct a current in DC...
  48. H

    Principal frequencies of a Waveform

    Homework Statement Identify the principal frequencies in the current waveform Homework EquationsThe Attempt at a Solution From the excel file, I have identified 3 principle frequencies at 52Hz, 246Hz and 351Hz. Is this correct? What does the term principle frequency actually mean?
  49. M

    Fourier series and sketch the waveform

    Homework Statement Sketch the waveform defined below and explain how you would obtain its Fourier series: f(wt) = 0 for 0 ≤wt ≤pi/2 (w=omega) f(wt) = Vsin(wt) for pi/2 ≤wt ≤pi f(wt) = 0 for pi ≤wt ≤3pi/2 f(wt) = Vsin(wt) for 3pi/2 ≤wt ≤2pi Develop the analysis as far as you are...
  50. ilovescience85

    Proportional + Derivative Controller output waveform

    Homework Statement FIGURE 5 shows a proportional plus derivative controller that has aproportional band of 20% and a derivative action time of 0.1 minutes. Construct the shape of the output waveform for the triangular input waveform shown, if the input rises and falls at the rate of 4 units...