-/ 2 
eh ate ves a (20) 
or, using Plancherel's theorem’, 
of 
Z.s acl“ pce!" Aw (21) 
—od 
Using equation (10), the energy flux in the reflected 
wave is given by 
6 GAS pen ep C219 |* deo 
ge” f | pcvs)]” Aw (22) 
Comparing equations (21) and (22) it is seen that: 
E, = 5. 
1483 
Equation (22) also shows that despite the distortion of the shape 
of the pulse, the distribution of energy in the Fourier spectrum 
remains unaltered upon reflection. 
2.5 The preceding development, leading to equation (18) is 
simply a more elegant and rigorous treatment of the material 
~T- 
