AP(t=2AP cos(om t)sin(@,t) 2 In Fig 19-13, the ear △P(t would perceive a tone at a frequency @av On,≈01≈O2 △P2( MAAAAAMA Since @1 the (a) amplitude frequency Oamp is small. The amplitude 2APm cos(oam t) fluctuates slowly Fig 19-13In Fig19-13, the ear would perceive a tone at a frequency . Since ~ , the amplitude frequency is small. The amplitude fluctuates slowly. amp 1 2 av 1 2 av (a) (b) Fig 19-13 ( ) 2 P t ( ) 1 P t t t t P(t) 2 P cos( t)sin( t)  =  m amp a v 1 ~ 2 av ~ 1 ~ 2 | 2 P cos( t)|  m amp