I I Exercises 291 a) 1s x ( f ) rt.al-\iaiucd? What, :symmetry docs ~ ( thave‘! ) b) The signal x c l ( t )is created by critical sampling of ~ ( t )Give the sampling frequency and the sample interval 7,, for this c Sketch X,(.?W) for U,) = Sn and for wy = 2n c) Sketch Xa(7w‘)for sampling with f a = and wY as above WO Exercise 11,19 The signal s(f)with the sketched spectiinn X ( j w ) is rriotliilated with the shown a r r angrinent complex modulation XO’O,) e~~l’clt, coo = 105 - - a) Sketch the spectrum Y(,?w) of the output signal b) Draw a11 arrmngement of sampler and reconslrnctioir filter N ( p ) that caii deniodiil&e y ( t ) so that x ( t ) is obtained at the output, What are the possible sampling lrequeucies? S1rt.tc.h I H(.Jw)I tor a suitable reconstruction fil1,c.r Exercise 11.20 A signal with the sketched spectrum is sampled ideally w k h intervals T 1XO’to)