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 system 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 linear 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. Differentiate 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 convolution 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 time 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.

28. What is the procedure to design a digital Butterworth filter? 29. What is the difference 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, and 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.

Advantages

cost lesserFaster computationsLess hardware, computationsEasier to designLower order required

FIR IIR

StableHighly preciseFinite duration impulse responseExcellent phase responseThe word-size effect such as round-off

noise and coefficient quantization errors are much less severe in FIR.

Disadvantages

Require higher orderIncreased hardwareMore computationsLarger input and output

delaysCost more

Sensitive to data round off and cutoff

Make become unstable Poor phase response

FIR IIR

Signal

CollectorRaw Data

ProcessorRefined

Data

Signal

Real-TimeSignal

ProcessorRefined

Data

33. What is a Digital Signal Processor (DSP)?Microprocessor specifically designed 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. Differentiate 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-clockcomplex instructions

Small code sizes

Poor C compilers

35. Differentiate between General purpose MPU(Micro Processor Unit) and DSP

ProcessorMPU 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 real-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 ArithmeticVarying internal formatMultiple memory accessSpecial addressing modeVery large internal memory

Microprocessor General purposeFixed internal formatSingle memory accessGeneral addressing modeVery 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 fixed point processor are :

i. cheaperii. smaller

iii. less power consumingiv. Harder to program

1. Watch for errors: truncation, overflow, roundingv. Limited dynamic range

vi. Used in 95% of consumer products floating point processors

i. have larger accuracyii. are much easier to program

iii. can access larger memoryiv. 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?43. Explain Von-Neumann and Harvard architectures

PipelinePipelineStageStage

PFPF

D D

EE Execute instructionExecute instruction

Route opcode to functional unitRoute opcode to functional unit Decode instructionDecode instruction

Generate program fetch addressGenerate program fetch addressRead opcodeRead opcode

DescriptionDescription

Floating Point Fixed Point

ApplicationsModemsDigital Subscriber Line (DSL)Wireless Base stationsDigital Imaging3D GraphicsSpeech RecognitionVoice over IP

ApplicationsPortable Products2G, 2.5G and 3G Cell PhonesDigital Audio PlayersDigital Still CamerasVoice RecognitionHeadsetsFingerprint Recognition

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 data

44. What are Line-in, Line-out, Mic-in, Mic-out?

Reference: Digital signal processing by Dr. Ganesh Rao & Vineeta P. Gejji. Texas instruments materials.