dsp lab sample viva questions
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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 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.