aT sln— COS OT d 2T2 0,其它⎪ ⎪ ⎪ ⎩ ⎪ ⎪ ⎪ ⎨ ⎧ = < ∫ = ∞+ . ,0 ; 2 || , 4 π ; 2 || , 2 π d cos 2 sin 0 其它 τ τ ω ω ωτ ωτ t t 5