5.1.1 Ideal Frequency-Selective Filters Ideal bandpass filter hae）h.e）.ey6: others hon-sinon s nan -oo<n<oo πn πn .Noncausal,not computationally realizable ◆no phase distortion 1H(e） -π-02 02π 75.1.1 Ideal Frequency-Selective Filters ◆Ideal bandpass filter 0 c1 c1 − −  ( ) j H e  1 −c2 c2 7 ◆Noncausal, not computationally realizable ◆no phase distortion   2 1 sin , sin c c bp n n h n n n n     = − −  ( ) 1 ( ) ( )  1 2 2 , | | 0, j 1 lp j p c c l bp H ej oth s H H e er e         − = =