DSP Lab - SAMPLE viva questions

yakzephyrAI and Robotics

Nov 24, 2013 (3 years and 8 months ago)

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DSP Lab
-

SAMPLE viva questions


1.

What is MATLAB?

2.

What are the applications of MATLAB?

3.

State sampling theorem.

4.

What is meant by Nyquist rate and Nyquist criteria?

5.

Explain scaling and superposition properties of a system.

6.

What is meant by linearity of a syst
em and how it is related to scaling and
superposition?

7.

What is impulse function?

8.

What is meant by impulse response?

9.

What is energy signal? How to calculate energy of a signal?

10.

What is power signal? How to calculate power of a signal?

11.

Differentiate between
even and odd signals.

12.

Explain time invariance property of a system with an example.

13.

What is memory less system?

14.

When a system is said to have memory?

15.

What is meant by
causality?

16.

Explain linear convolution and circular convolution.

17.

What is the length of lin
ear and circular convolutions if the two sequences are
having the length n1 and n2?

18.

What are Fourier

series and Fourier
transform
?

19.

What are the advantages and special applications of Fourier transform, Fourier
series, Z transform and Laplace transform?

20.

Dif
ferentiate between DTFT and DFT. Why it is advantageous to use DFT in
computers rather than DTFT?

In DTFT, frequency appears to be continuous. But, in DFT, frequency is discrete.
This property is useful for computation in computers.

21.

How to perform linear
convolution using circular convolution?

If two signals x (n) and y (n) are of length n1 and n2, then the linear convoluted
output z (n) is of length n1+n2
-
1.
Each of the input
signals

is
padded with zeros to
make it of length n1+n2
-
1. Then circular convolu
tion is

done on zero padded
sequences to get the linear convolution of original input sequences x (n) and y (n).

22.

What is meant by correlation?

Correlation is the measure of similarity between two signal/waveforms.
It
compares the waveforms at different tim
e instants.

23.

What
is

auto
-
correlation
?

It is a measure of similarity
of similarity of a signal/waveform with itself.

24.


What is

cross
-
correlation?

25.

What are the advantages of using
autocorrelation and cross correlation

properties in
signal processing fields?

26.

How auto
-
correlation can be used to detect the presence of noise?

27.

Differentiate between IIR filters and FIR filters.

Signal

Real
-
Time

Signal

Processor

Refined

Data




28.

What is the procedure to
design a digital Butterworth filter?

29.

What is the diff
erence between Butterworth, Chebyshev I and Chebyshev II filters?

30.

What are difference equations and differential equations?

31.

What is non real time processing?


32.

What is meant by real time processing?



Ability to collect, analyze, a
nd modify signals in real
-
time



Real
-
Time: As these signals are occurring



We

can

analyze and process signals while collecting them, not at a later
time.


Disadv
antages



Require higher order



Increased hardware



More computations



Larger input and
output delays



Cost more



Sensitive to data
round off and cutoff



Make become
unstable



Poor phase response




FIR




IIR

Advantages



cost lesser




Faster computations




Less hardware, computations



Easier to design




Lower order required




FIR








IIR




Stable



Highly precise



Finite duration impulse response



Excellent phase response



The word
-
size effect such as round
-
off noise and coeffici
ent
quantization errors are much less
severe in FIR.

Signal

Collec
tor

Raw
Data

Processor

Refined

Data



33.

What is a Digital Signal Processor (DSP)?

Microprocessor specifically de
signed to perform fast DSP operations (e.g., Fast
Fourier Transforms, inner products, Multiply & Accumulate)



Good at arithmetic operations (multiplication/division)



Mostly programmed with Assembly and C through Integrated
Development Environment (IDE)

34.

Diff
erentiate between RISC and CISC architectures.


RISC

Emphasis
on
software

Single
-
clock,

reduced
instruction
only

large
code
size

Better C
compilers

CISC

Emphasis
on
hardware

Includes
multi
-
clock

complex
instructions

Small
code
sizes

Poor C
compilers



35.

D
ifferentiate between General purpose MPU(Micro Processor Unit) and DSP
Processor

MPU are built for a range of general
-
purpose functions such as
:

Data manipulation

Math calculations

Control systems

They run large blocks of software

They are used in rea
l
-
time and in unreal
-
time systems

DSPs are single
-
minded, dedicated to:


Perform mathematical calculations

Small blocks of software

Have a predictable execution time

Real
-
time only

Could assist a general
-
purpose host MPU


36.

What is pipelining?

DSP


Arithmetic

Varying internal format

Multiple memory access

Special addressing mode

Very large internal memory


Microprocessor

General purpose

Fixed internal format

Single memory access

General a
ddressing mode

Very large external memory


37.

What is parallel processing?

38.

What is MAC?

39.

What is barrel shifter? Why it is advantageous to use it in DSP processor?

40.

Differentiate between floating point DSP and fixed point DSP.

41.

Fixed Point/Floating Point



f
ixed point processor are :

i.

cheaper

ii.

smaller

iii.

less power consuming

iv.

Harder to program

1.

Watch for errors: truncation, overflow, rounding

v.

Limited dynamic range

vi.

Used in 95% of consumer products



floating point processors

i.

have larger accuracy

ii.

are much easier to prog
ram

iii.

can access larger memory

iv.

It is harder to create an efficient program in C on a fixed point
processors than on floating point processors



42.

What is code composer studio?

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Fixed Point

A
pplications


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43.

Explain Von
-
Neumann and Harvard architectures




Von Neumann Architecture

:
Single memory shared by both the
program instructions and data





Harvard Architecture

:
Two separate memories, a program memory
(PM) for instructions, and a data memory (DM) for dat
a


44.

What
are L
ine
-
in, L
ine
-
out, Mic
-
in, Mic
-
out?


Reference:

Digital signal processing by Dr. Ganesh Rao & Vineeta P. Gejji.







Texas instruments materials.