Sine wave Definition and 118 Threads

A sine wave or sinusoid is a mathematical curve that describes a smooth periodic oscillation. A sine wave is a continuous wave. It is named after the function sine, of which it is the graph. It occurs often in both pure and applied mathematics, as well as physics, engineering, signal processing and many other fields. Its most basic form as a function of time (t) is:

where:

A, amplitude, the peak deviation of the function from zero.
f, ordinary frequency, the number of oscillations (cycles) that occur each second of time.
ω = 2πf, angular frequency, the rate of change of the function argument in units of radians per second




φ


{\displaystyle \varphi }
, phase, specifies (in radians) where in its cycle the oscillation is at t = 0. When



φ


{\displaystyle \varphi }
is non-zero, the entire waveform appears to be shifted in time by the amount φ/ω seconds. A negative value represents a delay, and a positive value represents an advance.
The sine wave is important in physics because it retains its wave shape when added to another sine wave of the same frequency and arbitrary phase and magnitude. It is the only periodic waveform that has this property. This property leads to its importance in Fourier analysis and makes it acoustically unique.

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  1. N

    What is the PDF of a Sine Wave Cycle?

    Does anybody know what the pdf of a sine wave cycle is? Or perhaps how to derive it? The problem can be done numerically, but surely there is an analytic expression for this function? There is a numerical solution available at...
  2. T

    Bidirectional pure sine wave inverter

    Hello All: A project of mine requires a bi-directional inverter that will take a 12VDC (most likely) battery to single phase 120VAC pure sine wave for utility tie (mains power). I will also require the inverter to be able to rectify to utility's power to charge the battery as well. Since...
  3. P

    RMS of Fullwave rectified sine wave.

    Homework Statement Determine the RMS value of fullwave rectified sine wave.Homework Equations RMS = \sqrt{({1}/{b-a})\int^{b}_{a}[(fx)]^{2}dx} The Attempt at a Solution Notes: The Period of a full wave rectified sine wave is pi. a=0 b=pi Let's do square root at the end. =1/pi...
  4. D

    Solve 2sin(2x): Table of Values & Graph (-π to π)

    I have a question that says: prepare a table of values and plot the graph for the domain (-pie,pie) for the function f(x)=2sin(2x) I understand how to do that for y=sinx, but for this function the wave compresses horizontally and stretches vertically so isn't the domain now (-pie/2,pie/2) and...
  5. D

    Solving 2sin(2x): Table of Values & Graph

    I have a question that says: prepare a table of values and plot the graph for the domain (-pie,pie) for the function f(x)=2sin(2x) I understand how to do that for y=sinx, but for this function the wave compresses horizontally and stretches vertically so isn't the domain now (-pie/2,pie/2) and...
  6. L

    Is a gaussian distribution 'like a sine wave'

    So I was having a conversation with the guy I share an office with and I brought up the gaussian distribution to show the probability distribution of energies of electrons generated by a filament. He mentioned that it 'looks like a sine wave', and I said 'sorta, but it's not a sine wave'. He...
  7. E

    Creating Sine Wave - Oscillator/Chips for 100kHz Output

    Trying to create a sine wave. Any oscillator or chips that do it? Looking at 100kHz. Seems like most of the oscillators i find put out 0~3.3/5V square wave. But i am m looking for -2.5~2.5V 100kHz sine wave output. I would think the chips create the square wave by taking the sine wave and...
  8. T

    What is the formula for rise/fall time of a sine wave?

    Does anyone remember the formula for the rise/fall time for a sine wave...? I thought I could calculate it but I did it wrong apparently t1. V_o sin(2*\pi*f*t)=.1 V_o \frac{arcsin(.1)}{2 \pi f} t2. V_o sin(2*\pi*f*t)=.9 V_o \frac{arcsin(.9)}{2 \pi f} t2-t1... but that isn't right
  9. X

    How is the RMS of a Sine Wave Derived?

    rms of sine wave = peak * 1/SQRT(2) how is this derived from the rms equation? (Search engines have returned no useful results.)
  10. J

    Power of a Sine Wave: Formula to Calculate W

    Hello, What is the formula to calculate the power (W) of a sine wave electrical signal traveling through a wire if I know the frequency, voltage, and current? Thanks, Jason O
  11. L

    Constructing a Circuit to Limit Voltage of 20V Peak-to-Peak Sine Wave

    How do I construct a circuit that will limit the positive half of a 20V peak-to-peak sine wave to 5.6V and the negative half to -2.5V? So far, I have a 1 k ohm resistor and the diode is forward biased leading to VL and Vout.
  12. S

    Defining Sine Waves for Scientists

    Dear All, I have an apparatus that produces a graph of results that looks to me like a sine wave (a half wave plate affecting the power throughput of a laser; it goes from maximum to minimum 4x throughout its 360º rotation). My problem is that I need to define this line as a formula but have...
  13. W

    What is the Best Way to Determine x Given y in a Sine Wave Algorithm?

    Hi, This maths stuff is tstarting to hurt my head! :p Ok, I want to use a sine wave to make objects appear at an increasing rate and then a decreasing rate. e.g. where: y=sin(x) y = interval before next object appears so in Maple that'd be: plot(sin(x)+1,x=Pi/2..Pi+(Pi/2)); Now I...
  14. F

    Sine Wave or Spiral: Exploring the 3-Dimensional Nature of Electromagnetic Waves

    Perhaps this has already been brought up, but is an electromagnetic wave 2-dimensional or 3-dimensional? The current "up-and-down" concept does not have me convinced. If you look at a standard spring, you can see that it is a spiral/helix. You can also see that the side of the spring...
  15. S

    How does a 3D sine wave appear on a graph?

    What does a three-dimensional sine wave look like? -Sam
  16. I

    Who knows how to make a simple sine wave oscillator?

    Hi. I want some information about how to make this. But that's not the prob. the prob. is that you can only use: Diodes (Normal & zener), capacitors, inductors & resistors, U can not use complex devices. If U know something, please reply this message. Thanks. Ingyil. Colombia, S.A.
  17. J

    Simple Sine Wave Oscillator Circuit I think this diagram is incorrect

    i was given this circuit diagram by one of my instructors this past winter (summer for you americans) so.. i tried 2 build it. three times i tried, it didnt work. twice on a copper board, once on a projectboard. the instructor & i checked them each over numerous times... he even tried to...
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