5. What are diphthongs? 6. Why we require sampling of analog signals? 7. Why we generally keep sampling frequency more t
Mohit Goel
Assignment-1
Speech and Audio Processing
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1. What are the applications of speech processing? 2. What are the differences between voiced and unvoiced speech signals? 3. What is the difference between pitch frequency and formant frequency of the speech signal? 4. How can we say that we can obtained a same results using a “two pole system” as that of a “single zero system”? 5. What are diphthongs? 6. Why we require sampling of analog signals? 7. Why we generally keep sampling frequency more than Nyquist rate for sinusoidal signals? 8. What are the assumptions uses while designing a uniform quantizer? 9. What are the advantages of a logarithmic quantizer over a uniform quantizer? 10. Write the mathematical expression of system function for excitation process used in discrete time model of speech processing? 11. What is the basic principle of delta modulation? 12. Why we keep sampling frequency much higher than Nyquist rate in delta modulation? 13. What is granular noise problem? 14. What is slope over load problem? 15. Why a µ law quantizer is better than a simple logarithmic quantizer? 16. X(t)= 3 cos (2000πt) + 5 sin (6000πt) + 10 cos(12000 πt) What is nyquist frequency and nyquist interval for given signal? 17. What is Jaynt algorithm to select step size in adaptive delta modulation? 18. Explain speech production and speech recognition mechanism using block diagram? 19. Explain human speech production mechanism? 20. What are the formant frequencies of a speech signal and what are the different range of formant frequencies and why we don’t care about higher order formant frequencies? 21. Explain discrete time model of speech production? 22. What is difference between mid rise and mid tread quantizer? Find the expression for SNR in a uniform quantizer? 23. Why are the advantages of logarithmic quantizer over uniform quantizer? Prove that SNR of a logarithmic quantizer is independent of signal variance? 24. What is µ law quantizer? Why a µ law quantizer is better than a simple logarithmic quantizer? 25. Explain the working of linear delta modulation? What are the disadvantages or problems in linear delta modulation, explain them?
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Mohit Goel
Assignment-1
m
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itg
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l4
u. bl og sp
bit quantization system?
ot .c
om
26. Explain the working of adaptive delta modulation and how its removes the problems which exist in linear delta modulation? 27. A digital link carries binary coded words representing samples of signals: X(t)= 3 cos (600 πt) + 2 cos (1800 πt) The link operated on 40000 bits per seconds and each sample is quantized into 1024 different voltages levels. (i) What is sampling frequency and folding frequency? (ii) What is nyquist rate for the signal? (iii) What is step size ∆ ? (iv) What is the discrete time signal obtained after sampling? 28. A speech signal is processed in a TV using 3 bit uniform quantizer. Find the SNR value of system. Assume that Xmax = 8 σ x . What will be the improvement in SNR if we use a four
