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Find the steady-state variance of the noise in the output due to quantization of input for the first order filter y(n)=ay(n-1)+x(n).
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written 2.4 years ago by |
Solution:
Given y(n)=ay(n−1)+x(n)Y(z)=az−1Y(z)+X(z)Y(z)−az−1Y(z)=X(z)Y(z)[1−az−1]=X(z)H(z)=Y(z)X(z)=11−az−1=zz−aH(z−1)=z−1z−1−a
σ2ε=σ2e12πj∮CA(z)H(z−1)z−1dz=σ2e12πj∮czz−az−1z−1−az−1dz=σ2e12πj∮cz−1(z−a)(z−1−a)dz
σ2ε=σ2e[ residue of z−1(z−a)(z−1−a) at =σ2e[(z−a)z−1(z−a)(z−1−a)]|z=a=σ2e[1/a(1/a−a)]=σ2e[11−a2].