Explore topic-wise MCQs in Digital Signal Processing Questions and Answers.

This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Signal Processing Questions and Answers knowledge and support exam preparation. Choose a topic below to get started.

1.

In the equation x(t) = a(t)cos[2πFct+θ(t)], Which of the following relations between a(t) and x(t), θ(t) and x(t) are true?

A. a(t), θ(t) are called the Phases of x(t)
B. a(t) is the Phase of x(t), θ(t) is called the Envelope of x(t)
C. a(t) is the Envelope of x(t), θ(t) is called the Phase of x(t)
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
2.

What is the possible representation of x(t) if xl(t)=a(t)e(jθ(t))?

A. x(t) = a(t) cos[2πFct – θ(t)]
B. x(t) = a(t) cos[2πFct + θ(t)]
C. x(t) = a(t) sin[2πFct + θ(t)]
D. x(t) = a(t) sin[2πFct – θ(t)]
Answer» C. x(t) = a(t) sin[2πFct + θ(t)]
Discussion
3.

If a possible representation of a band pass signal is obtained by expressing xl (t) as \(x_l (t)=a(t)e^{jθ(t})\) then what are the equations of a(t) and θ(t)?

A. a(t) = \(\sqrt{u_c^2 (t)+u_s^2 (t)}\) and θ(t)=\(tan^{-1}\frac{u_s (t)}{u_c (t)}\)
B. a(t) = \(\sqrt{u_c^2 (t)-u_s^2 (t)}\) and θ(t)=\(tan^{-1}\frac{u_s (t)}{u_c (t)}\)
C. a(t) = \(\sqrt{u_c^2 (t)+u_s^2 (t)}\) and θ(t)=\(tan^{-1}\frac{u_c (t)}{u_s (t)}\)
D. a(t) = \(\sqrt{u_s^2 (t)-u_c^2 (t)}\) and θ(t)=\(tan^{-1}⁡\frac{u_s (t)}{u_c (t)}\)
Answer» B. a(t) = \(\sqrt{u_c^2 (t)-u_s^2 (t)}\) and θ(t)=\(tan^{-1}\frac{u_s (t)}{u_c (t)}\)
Discussion
4.

In the equation x(t) = Re\([x_l (t) e^{j2πF_c t}]\), What is the lowpass signal xl (t) is usually called the ___ of the real signal x(t).

A. Mediature envelope
B. Complex envelope
C. Equivalent envelope
D. All of the mentioned
Answer» C. Equivalent envelope
Discussion
5.

In the relation, x(t) = \(u_c (t) cos⁡2π \,F_c \,t-u_s (t) sin⁡2π \,F_c \,t\) the low frequency components uc and us are called _____________ of the bandpass signal x(t).

A. Quadratic components
B. Quadrature components
C. Triplet components
D. None of the mentioned
Answer» C. Triplet components
Discussion
6.

If we substitute the equation \(x_l (t)= u_c (t)+j u_s (t)\) in equation x (t) + j ẋ (t) = xl(t) ej2πFct and equate real and imaginary parts on side, then what are the relations that we obtain?

A. x(t)=\(u_c (t) \,cos⁡2π \,F_c \,t+u_s (t) \,sin⁡2π \,F_c \,t\); ẋ(t)=\(u_s (t) \,cos⁡2π \,F_c \,t-u_c \,(t) \,sin⁡2π \,F_c \,t\)
B. x(t)=\(u_c (t) \,cos⁡2π \,F_c \,t-u_s (t) \,sin⁡2π \,F_c \,t\); ẋ(t)=\(u_s (t) \,cos⁡2π \,F_c t+u_c (t) \,sin⁡2π \,F_c \,t\)
C. x(t)=\(u_c (t) \,cos⁡2π \,F_c t+u_s (t) \,sin⁡2π \,F_c \,t\); ẋ(t)=\(u_s (t) \,cos⁡2π \,F_c t+u_c (t) \,sin⁡2π \,F_c \,t\)
D. x(t)=\(u_c (t) \,cos⁡2π \,F_c \,t-u_s (t) \,sin⁡2π \,F_c \,t\); ẋ(t)=\(u_s (t) \,cos⁡2π \,F_c \,t-u_c (t) \,sin⁡2π \,F_c \,t\)
Answer» C. x(t)=\(u_c (t) \,cos⁡2π \,F_c t+u_s (t) \,sin⁡2π \,F_c \,t\); ẋ(t)=\(u_s (t) \,cos⁡2π \,F_c t+u_c (t) \,sin⁡2π \,F_c \,t\)
Discussion
7.

What is the equivalent time domain relation of xl(t) i.e., lowpass signal?

A. \(x_l (t)=[x(t)+j ẋ(t)]e^{-j2πF_c t}\)
B. x(t)+j ẋ(t) = \(x_l (t) e^{j2πF_c t}\)
C. \(x_l (t)=[x(t)+j ẋ(t)]e^{-j2πF_c t}\) & x(t)+j ẋ(t) = \(x_l (t) e^{j2πF_c t}\)
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
8.

What is the equivalent lowpass representation obtained by performing a frequency translation of X+(F) to Xl(F)= ?

A. X+(F+Fc)
B. X+(F-Fc)
C. X+(F*Fc)
D. X+(Fc-F)
Answer» B. X+(F-Fc)
Discussion
9.

If the signal ẋ(t) can be viewed as the output of the filter with impulse response h(t) = 1/πt, -∞ < t < ∞ when excited by the input signal x(t) then such a filter is called as __________

A. Analytic transformer
B. Hilbert transformer
C. Both Analytic & Hilbert transformer
D. None of the mentioned
Answer» C. Both Analytic & Hilbert transformer
Discussion
10.

In equation \(x_+ (t)=F^{-1} [2V(F)]*F^{-1} [X(F)]\), if \(F^{-1} [2V(F)]=δ(t)+j/πt\) and \(F^{-1} [X(F)]\) = x(t). Then the value of ẋ(t) is?

A. \(\frac{1}{π} \int_{-\infty}^\infty \frac{x(t)}{t+τ} dτ\)
B. \(\frac{1}{π} \int_{-\infty}^\infty \frac{x(t)}{t-τ} dτ\)
C. \(\frac{1}{π} \int_{-\infty}^\infty \frac{2x(t)}{t-τ} dτ\)
D. \(\frac{1}{π} \int_{-\infty}^\infty \frac{4x(t)}{t-τ} dτ\)
Answer» C. \(\frac{1}{π} \int_{-\infty}^\infty \frac{2x(t)}{t-τ} dτ\)
Discussion
11.

In time-domain expression, \(x_+ (t)=F^{-1} [2V(F)]*F^{-1} [X(F)]\). The signal x+(t) is known as

A. Systematic signal
B. Analytic signal
C. Pre-envelope of x(t)
D. Both Analytic signal & Pre-envelope of x(t)
Answer» E.
Discussion
12.

What is the equivalent time –domain expression of X+(F)=2V(F)X(F)?

A. F(+1)[2V(F)]*F(+1)[X(F)]
B. F(-1)[4V(F)]*F(-1)[X(F)]
C. F(-1)[V(F)]*F(-1)[X(F)]
D. F(-1)[2V(F)]*F(-1)[X(F)]
Answer» E.
Discussion