13.07.2015 Views

Mathematical Methods for Physics and Engineering - Matematica.NET

Mathematical Methods for Physics and Engineering - Matematica.NET

Mathematical Methods for Physics and Engineering - Matematica.NET

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

INTEGRAL TRANSFORMS13.18 The equivalent duration <strong>and</strong> b<strong>and</strong>width, T e <strong>and</strong> B e , of a signal x(t) are definedin terms of the latter <strong>and</strong> its Fourier trans<strong>for</strong>m ˜x(ω) byT e = 1 ∫ ∞x(t) dt,x(0) −∞B e = 1 ∫ ∞˜x(ω) dω,˜x(0) −∞where neither x(0) nor ˜x(0) is zero. Show that the product T e B e =2π (this is a<strong>for</strong>m of uncertainty principle), <strong>and</strong> find the equivalent b<strong>and</strong>width of the signalx(t) =exp(−|t|/T ).For this signal, determine the fraction of the total energy that lies in the frequencyrange |ω| |a|;2464

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!