What is Parseval's theorem: Definition and 14 Discussions
In mathematics, Parseval's theorem usually refers to the result that the Fourier transform is unitary; loosely, that the sum (or integral) of the square of a function is equal to the sum (or integral) of the square of its transform. It originates from a 1799 theorem about series by Marc-Antoine Parseval, which was later applied to the Fourier series. It is also known as Rayleigh's energy theorem, or Rayleigh's identity, after John William Strutt, Lord Rayleigh.Although the term "Parseval's theorem" is often used to describe the unitarity of any Fourier transform, especially in physics, the most general form of this property is more properly called the Plancherel theorem.
Hi,
So I have a quick conceptual question about Parseval's theorem in this application. In previous parts of this question, we have found the average powers of both f(t) and g(t) by integration and using the complex Fourier series respectively (not sure if this is relevant to my question)...
Given a function F(t)
$$ F(t) = \int_{-\infty}^{\infty} C(\omega)cos(\omega t) d \omega + \int_{-\infty}^{\infty} S(\omega)sin(\omega t) d \omega $$
I am looking for a proof of the following:
$$ \int_{-\infty}^{\infty} F^{2}(t) dt= 2\pi\int_{-\infty}^{\infty} (C^{2}(\omega) + S^{2}(\omega)) d...
Hello good folks!
I'm stuck trying to solve the problem b). In the theory book examples they are skipping steps and shortly states 'use algebra' and parsevals theorem to rewrite the Fourier series into the answer that is given.
So I've tried to use parsevals theorem but I still can't rewrite...
Homework Statement
Hi guys,
I have the following transmitted power signal:
$$x(t)=\alpha_m \ cos[2\pi(f_c+f_m)t+\phi_m],$$
where: ##\alpha_m=constant, \ \ f_c,f_m: frequencies, \ \ \theta_m: initial \ phase.##
The multipath channel is:
$$h(t)=\sum_{l=1}^L \sqrt{g_l} \ \delta(t-\tau_l).$$...
Self Study
1. Homework Statement
Consider a periodic function f (x), with periodicity 2π,
Homework Equations
##A_{0} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)dx##
##A_{n} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)cos\frac{2\pi rx}{L}dx##
##B_{n} =...
Homework Statement
[/B]
Suppose we have a 2\pi-periodic, integrable function f: \mathbb{R} \rightarrow \mathbb{C} whose Fourier coefficients are known. Parseval's theorem tells us that:
\sum_{n = -\infty}^{\infty}|\widehat{f(n)}|^2 = \frac{1}{2\pi}\int_{-\pi}^{\pi}|f(x)|^{2}dx,
where...
Homework Statement
Using Parseval's theorem,
$$\int^\infty_{-\infty} h(\tau) r(\tau) d\tau = \int^\infty_{-\infty} H(s)R(-s) ds$$
and the properties of the Fourier transform, show that the Fourier transform of ##f(t)g(t)## is
$$\int^\infty_{-\infty} F(s)G(\nu-s)ds$$
Homework Equations...
Homework Statement
By applying Parseval's (Plancherel's) theorem to the function are given by:
f(x) = -1 for -2 ≤ x < 0
1 for 0 ≥ x < 2
0 otherwise
determine the value of the following integral.
∫ dk sin^4(k)/(k^2) (Integral between ±infinity)
Homework Equations...
Homework Statement
I'm given the following function
f(x) = \begin{cases} x &-2<x<2\\ f(x+4) &\mbox{otherwise} \end{cases}
And I'm asked to find the Fourier sine series. Then I'm supposed to use Parseval's theorem to obtain a certain sum.
Homework Equations
Since I have a sine Fourier...
Homework Statement
Show that: \sum_{n=1}^{\infty}\frac{1}{n^4} = \frac{π^4}{90}
Hint: Use Parseval's theorem
Homework Equations
Parseval's theorem:
\frac{1}{\pi}\int_{-\pi}^{\pi} |f(x)|^2dx = \frac{a_0^2}{2}+\sum_{n=1}^{\infty}(a_n^2+b_n^2)
The Attempt at a Solution
I've been trying to solve...
A square wave has amplitude 3 and period 5. calculate its power?
Using Fourier series for this square wave and Parseval’s
theorem, calculate the power in a signal obtained by cutting out frequencies
above 1 Hz in the square wave?
i am able to obtain the Fourier series for the square wave...
Homework Statement
The Fourier series for f(x) = x2 over the interval (−1/2, 1/2) is:
f(x) = \frac{1}{12}-\frac{1}{\pi^2} (cos 2\pi x - \frac{1}{2^2}cos4\pi x + \frac{1}{3^2}cos6\pi x) ...
Using Parseval's Theorem, show that
\sum _{n = 1}^\infty \frac{1}{n^4} = \frac{\pi^4}{90}...
Homework Statement
Hi all.
Please take a look at the lowest equation in this picture:
http://img143.imageshack.us/img143/744/picture2ao8.png
This is Parselvals Identity.
Let us say that I am given a Fourier series of f(x), and I want to calculate the integral of f(x)^2 from -L to...