ANNA UNIVERSITY OF TECHNOLOGY EXAMINATIONS FOR SECOND YEAR THIRD SEMESTER CSE Students
141302 - Analog and digital Communication
UNIT I
1. Explain how Carson’s rule of bandwidth in FM is obtained. For an FM modulator with peak frequency deviation f=5 kHz modulating frequency fm=5kHz, with amplitude of carrier 5V and frequency 500 kHz, determine the bandwidth using Carson’s rule
2. Derive an expression for a single tone FM signal and draw its frequency spectrum.
3. Define amplitude modulation. Drive the relation between the total transmitted power and carrier power in an AM system when several frequencies simultaneously modulated acarrier.
4. Define FM and PM modulation, derive their equations.
5. In angle modulation, explain frequency devation, percentmodulation, phase deviation and modulation index with suitable example.
UNIT II
1. Explain with neat diagrams the FSK technique, transmitter and receiver blocks
2. With neat diagram explain the generation of a DPSK signal and recovering the data from
the DPSK signal
3. Explain quadrature amplitude modulation with the help of relevant diagrams.
4. Discuss the QPSK transmission system with relevant diagrams.
UNIT III
1. Explain PCM and differential PCM with the help of block diagrams.
2. Explain the basic principle of quantization and quantization error
3. What are the drawbacks of delta modulation and how are they overcome in adaptive delta
modulation? explain with the help of a neat block diagram
4. Describe DPCM transmitter and receiver with suitable block diagram.
UNIT IV
1. Explain the detail about the parallel interface with control signals and timing information
2. Explain the different types of data transmission
3. How are errors detected and corrected in data communication?
4. Discuss the following : Synchronous modem , Asynchronous modem ,Low speed modem ,medium and high speed modem
UNIT V
1. Explain fast and slow frequency hopping techniques used in spread spectrum.
2. With help of neat block diagram, explain DS spread spectrum system with coherent binary PSK
3. Compare TDMA,FDMA CSMA multiple access techniques.
4. Explain the working of multi pulse excited LPC and code excited LPC by suitable Diagrams
5. For a linear feedback shift register with three stages (m=3),evaluate the maximum length PN sequence for feedback taps =(3,1).Draw the schematic arrangement and verify all the properties of PN sequence in generated output. Sketch the sequence, its autocorrelation function and PSD function if chip rate is 10MHz.
