EC2301 DIGITAL COMMUNICATION Anna University Question Bank , Huge Question collections taken from previous year Anna University question Papers (very Useful) | Repeated Questions in Anna University Question Papers from all 5 units ..
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EC2301 DIGITAL COMMUNICATION
UNIT – I PART – A 1. Give an example for time limited and time unlimited signals.[MAY 2011] 2. Give the advantages and disadvantages of digital communication[May 2011] 3. Which parameter is called figure of merit of a digital communication system and why? [NOV 2010] 4. What is meant by distortion less transmission? [NOV 2010] 5. Define BER 6. What are the advantages of PAM? 7. What is meant by basis set? 8. What is the condition for orthogonal? 9. Define noise equivalent bandwidth 10. State Dimensionality theorem 11. What is GSOP? 12. Write the expression for bandwidth of digital signal. 13. Write the expression for Linear filter channel.
PART-B 1. Explain how PWM and PPM signals are generated.(16 ) [MAY 2011] 2. Classify channels. Explain the mathematical model of any two communication channels (16) [MAY 2011] 3. Draw a neat block diagram of a typical digital communication system and explain the function of the key signal processing blocks.( 16) [NOV 2010] 4. Distinguish between base band and bandpass signaling. (6) 5. Explain Binary symmetric channel and Gaussian channel with their mathematical models. (10) [NOV 2010] 6. Derive Geometrical representation of signal.(8) 7. Explain the procedure for obtaining from the basis set.(8) 8. Explain the mathematical models of communication channel 9. Explain the concept of PWM and PAM 10. Obtain the orthonormal basis function for the set of waveforms using GSOP
UNIT-II PART-A 1. State sampling theorem. [MAY 2011] 2. What is quantization error [MAY 2011] 3. Why is prefiltering done before sampling? [NOV 2010] 4. Define quantization noise power [NOV 2010] 5. State sampling theorem. (MAY/JUN2006/MAY/JUN2007, APR/MAY2008, NOV 2008) 6. What are the limitations of delta modulation? (APR/MAY2004,MAY/JUNE 2009) 7. What should be the pass band for anti aliasing and smoothing filters used with pulse modulation / demodulation systems? (NOV/DEC2004) 8. Why compressors are used in PCM? (NOV/DEC2004) 9. What is the interpolatory property for sinc function? (APR/MAY2005) 10. Draw the block diagram of transmitter and receiver sections of DPCM. (APR/MAY2005, MAY/JUNE 2009) 11. What do you under stand by the term aliasing? (NOV/DEC2005) 12. A band pass signal has the spectral range that extends from 20 kHz to 82 kHz. Find the acceptable range of sampling frequency fs. (NOV/DEC2005) 13. What is the SNR of PCM system if number of quantization levels is 28 ? (MAY/JUN2006) 14. State bandpass sampling theorem (MAY/JUNE 2006) 15. Define quantisation error. (MAY/JUNE2007,NOV/DEC 2008) 16. ) 17. A signal x(t)=5 cos (1000 Πt) is sampled and quantized using 8 bit PCM system. Find the signal to quantization noise ratio (NOV/DEC 2007) 18. State the principle of DPCM (APR/MAY2008) 19. Plot the magnitude spectrum of the ideally sampled version of the signal M(t)=2 cos (200 Πt) + 40 sin (290 Πt). Assume that the sampling rate is 1 KHz. (APR/MAY 2008) 20. Define pulse position modulation scheme with a suitable diagram. 21. Differentiate Noise and fading. (NOV/DEC 2008) 22. An analog signal is quantized and transmitted by using a PCM system. If each sample at the receiving end of the system must be known to within ± 0.5% of the peak to peak full scale value. How many digits must each sample contain (NOV/DEC 2008) 23. Define quantisation noise. (NOV/DEC 2008) 24. State sampling theorem for lowpass signals. (MAY/JUNE 2009) 25. What are the drawbacks of delta modulation. (MAY/JUNE 2009)
PART-B 1. Explain a uniform quantization process(8). [MAY 2011] 2. Write note on temporal waveform coding(8) [MAY 2010] 3. Explain a spectral waveform encoding process (8) [MAY 2011] 4. Compare various speeches encoding method(8) [MAY 2011] 5. State the nyquist sampling theorem.Demonstrate its validity for an analog signal having fourier transform x(f) which is zero outside the interval[-fm