This set of Digital Signal Processing Multiple Choice Questions & Answers (MCQs) focuses on “FIR Least Squares Inverse Filters”.

1. Wiener filter is an FIR least-squares inverse filter.**a) True**

b) False

2. If h(n) is the impulse response of an LTI system and h_{I}(n) is the impulse response of the inverse LTI system, then which of the following is true?

a) h(n).h_{I}(n)=1

b) h(n).h_{I}(n)=δ(n)

c) h(n)*h_{I}(n)=1**d) h(n)*h _{I}(n)=δ(n)**

3. If H(z) is the system function of an LTI system and H_{I}(z) is the system function of the inverse LTI system, then which of the following is true?

a) H(z)*H_{I}(z)=1

b) H(z)*H_{I}(z)=δ(n)**c) H(z).H _{I}(z)=1**

d) H(z).H

_{I}(z)=δ(n)

4. It is not desirable to restrict the inverse filter to be FIR.

a) True**b) False**

5. Which of the following method is used to restrict the inverse filter to be FIR?**a) Truncating h _{I}(n)**

b) Expanding h

_{I}(n)

c) Truncating H

_{I}(z)

d) None of the mentioned

6. What should be the length of the truncated filter?

a) M

b) M-1**c) M+1**

d) Infinite

7. Which of the following criterion can be used to optimize the M+1 filter coefficients?

a) Pade approximation method**b) Least squares error criterion**

c) Least squares error criterion & Pade approximation method

d) None of the mentioned

8. Which of the following filters have a block diagram as shown in the figure?

a) Pade wiener filter

b) Pade FIR filter

c) Least squares FIR filter**d) Least squares wiener filter**

9. The auto correlation of the sequence is required to minimize ε.**a) True**

b) False

10. Which of the following are required to minimize the value of ε?

a) r_{hh}(l)

b) r_{dh}(l)

c) d(n)**d) all of the mentioned**

11. FIR filter that satisfies ∑Mk=0bkrhh(k−l)=rdh(l), l=0,1,…M is known as wiener filter.**a) True**

b) False

12. What should be the desired response for an optimum wiener filter to be an approximate inverse filter?

a) u(n)**b) δ(n)**

c) u(-n)

d) none of the mentioned

13. If the set of linear equations from the equation ∑Mk=0bkrhh(k−l)=rdh(l), l=0,1,…M are expressed in matrix form, then what is the type of matrix obtained?

a) Symmetric matrix

b) Skew symmetric matrix**c) Toeplitz matrix**

d) Triangular matrix

14. What is the number of computations proportional to, in Levinson-Durbin algorithm?

a) M**b) M ^{2}**

c) M

^{3}

d) M

^{1/2}