8.4 CkJnvolut ion 167 a tirltil impulse Thr tlelt the hockey st i t k iiripiilse ticrr i s tlie idealized strilw of thr piick with observed displacement velocity 177 11" y ~ t w i~t ~ l ~ In Chaptcr we W ~ I Pintcrcsted for tlir firc;t time iii descdjing the trariskr properties of LTI-systenis, MF coiiltl show only rising the dofinitiorrs of liiicaiity arid tiiire-invariance that fimctions of the fox111 P q t arc cigenfurrctions of UI'I-svskms Iy to the svstrrn fiinrtiori as il system rzioctel of LTI-sv t he freclucnc3.-dornhin