Free Printable DSP PART-B MODEL-3

1.

The signal x(t)=e^-2tu(t) is

a)

power signal

b)

energy signal

c)

neither power nor energy signal

d)

either power or energy signal

2.

The signal $x\left(n\right)=\cos\ \frac{2\pi}{3}nu\left(n\right)\$ is

a)

causal,aperiodic

b)

causal,periodic

c)

non causal,aperiodic

d)

non causal,periodic

3.

The signal x(n)=cos2n is

a)

periodic with period $\pi$

b)

periodic with period 2

c)

periodic with period $4\pi$

d)

aperiodic

4.

The region of convergence of the z-transform of a unit step function is

a)

|Z| > 1

b)

|Z| < 1

c)

(Real part of z) > 0

d)

(Real part of z) < 0

5.

The z transform of the following real exponential sequence
x(n)= $a^n$ n $\ge$ 0

= 0 for n< 0 is given by

a)

$1-az^{-1\ };\left|z\right|\ >\ a$

b)

$\frac{1}{1-az^{-1\ }};\ \left|z\right|>a$

c)

$-\frac{1}{1-az};\ \left|z\right|>a$

d)

none

6.

A linear discrete time system has the characteristic equation z³-0.81z =0 the system is

a)

stable

b)

marginally stable

c)

unstable

7.

The number of complex multiplications required to calculate N-point DFT using radix-2 DIT-FFT algorithm is

a)

$\frac{N}{2}\log_{10}^N$

b)

$N\log_2\ N$

c)

$\frac{N}{2}\ \log_2\ N$

d)

NONE

8.

The direct evaluation DFT requires __________complex multiplications

a)

N(N-1)

b)

N²

c)

N(N+1)

d)

$\frac{N\left(N-1\right)}{2}$

9.

If X(K) is DFT of a sequence x(n) then DFT of real part of x(n) is

a)

X*K

b)

X*(N-K)

c)

$\frac{1}{2}\left[X\left(K\right)+X\cdot\left(N-K\right)\right]$

d)

$\frac{1}{2}\left[X\left(K\right)-X\cdot\left(N-K\right)\right]$

10.

I I R digital filters are of the following nature

a)

Recursive

b)

Non Recursive

c)

Reversive

d)

Non Reversive

11.

What is the disadvantage of impulse invariant method

a)

one to one mapping

b)

anti aliasing

c)

warping

d)

aliasing

12.

From the given specification find out the order of the filter using bilinear transformation of butterworth filter

$\Omega s=39.2522$ $\Omega p=12.2560$ AP=0.6 and AS=0.1

a)

1

b)

2

c)

4

d)

3

13.

Formula for linear type hanning window

a)

w_{c\ }\left(n\right)=0.5-0.5\cos\ \frac{2\pi n}{N-1}

b)

$w_c\left(n\right)=0.5+0.5\cos\ \frac{2\pi n}{N-1}$

c)

$w_H\left(N\right)=0.54+0.46\ \cos\ \frac{2\pi n}{N-1}$

d)

NONE

14.

find the four point DFT for the given sequence

x(n) = {1,1,0,0}

a)

x(k)={2,1-j,0,1+j}

b)

x(k)={2,1-j,0,j}

c)

x(k)={5,1-j,4,1+j}

d)

none

15.

D/A conversion is usually performed by combining a D/A converter with a sample-and-hold (S/H ) and followed by a low pass (smoothing) filter.

a)

True

b)

False

DSP PART-B MODEL-3

Total questions: 15

Worksheet time: 15mins

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