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Answer any five questions

1. (a)   Compare the relative merits of three different forms of pull-up for the inverter circuits. What is the best choice for realization in nMOS technology ?

b)         In the inverter araint, what is meant by Zp,n and Zp, d ? Derive the required ratio between Zp.u and Zp,d it an nMOS inverter is to be driven from another inverter.

2. a) Draw the stick diagram and a mask layout for an 8:1 nMOS inverter circuits. Both the input and output points should be on the polysilcon layer.

b)         Explain the steps how to draw a aranic diagram from the CMOS layout.

c)         Expalin the steps to                                                   multiplex circuit.


3. (a)   A particular layer of MOS circuit has  a resistivity P= 1 Ohm Cm. A section of this layer is 55mm long and 5mm wide and has a thickness of mm. calculate the resistance from one from one end of this section to the other (along the length). Use the concept of sheet resistance Rs. What is the value of Rs. ?

5.         Discuss with a suitable example to the design of a PLA-based finite state machine.

6.         Discuss in detail the general arrangement of a four-bit arithmetic preunor and the design steps.

7.         Carryout the design of a fourbit CMOS carry lookahead adder upto stick diagram form. The determine what standard cells are needed and design a mark layout for each.

8.         Write short notes on (any FOUR)

a)         Compound semiconductor

b)         GaAs devices

c)         CIF code

d)         Floor plan layout  e)Register cells.



1.   (a).            What do you mean by noise ? Descibe various types of noise we encounter in

      communication system engineering. Distinguish between Noise Temprature and Available Power.

(b) Define noise figure. Express the equivalent noise temperature of a cascade. Give an example of a receiving systems.


2.         Write notes on the following

a)         Noise Bandwidth

b)         Line coder/decoder implementation.

c)         Data communication protocol

d)         Modems

3.         (a)       A particular InGaAsP LED emitting at 1.29mM is found to have a radiative recombination coefficient of 3 x  10-10 cm3/s, a carrier concentration of n0 + P0 cm-3 in its 1-mm-thick active region, and a surface recombination velocity of 104 cm/s. Plot the frequency response of the relative optical output intensity 1 (w)/I0 of this LED for modulation frequencies ranging from 1-500 MHz at current densities of 0.5, 2.01 and 10.1 KA/cm2 what is the 3dB modulation bandwidth at each of these current densities.?


b)         Discuss the structure of the LASER diodes and their radiation patterns.

4.         a)         With neat diagram explain the propagation modes in the single-mode

optical fiber.

b)         Explain vapor phase anial decomposition method of optical fiber fabrication.

5.         a) What do you mean by attenuation? Express the attenuation units. Distinguish between Absorption and scattering losses and their causes.


b)         Write notes on the following

                        i)         Dispersion

                        ii)        Optical amplifier.

6.         (a)      Draw the schematic bloch diagram of a typical optical ]

communication system and explain.

b)         Draw the block diagram of a unidirectional WDM system that combines N independent input signals for transmission over a single fiber. Explain the principle of WDM. Also discuss how a bidirectional WDM system is implemented.


7.         (a)       What do you mean by a transpondor ? Explain the principle of

            operation of the transponder in connection with satellite communication system.

            (b)       Discuss various types of antenna systems used in satellite

                        communication systems.

            c)         Distinguish between Rep aters and Ground stations.


8.         Write short notes on any four :

a)         Up-down-Cross Link

b)         SONET/FDDI

c)         Optical detector

d)         XDSL

e)         Data Regenerator

f)         Noise BW

g)         Free path space losses.



1.         a) Define and explain what is meant by

            i)          aspect ratio

            ii)         interlaced scanning in a television.


b)         Half-line scanning is used in all television system – Explain.

If a television system sends 25 picture per second and has a 625 lines per picture, calculate the bandwidth required for video circuits. Assume data if required.


2)         a)         What is meant by VSB transmission Briefly explain how the

transmission plan is realized.

b)         Describe and explain, with block diagram, the operation of different parts of an inter-carrier type television  receiver.

3.         a)         Give the block diagram of a TV transmitter using low level IF


b)         What are the general characteristics of camera tubes used in a TV system ? Explain the principle of operation of a videcon tube.

4.         a)         Explain how the chrominance and the luminance signals are

multiplexed with the monochrome video bandwidth.

b)         How is antenna gain defined? How does the folded dipole differ from dipole antenna in performance ?

5          a)         State the paramentes controlling the detection range of a pulsed radar.

Derive the expression of power density of echo signal at the radar antenna.

b)         What considerations determine the pulse width and PRF of a radar sat? Explain with illustrations.

6.         Explain with block diagram, the principle of operation of an FMCW radar, having facility for measuring both range and speed of a moving target.

State the limitations of FMCW radar.

7.         a)         Describe a moving target indicator radar with the help of functional


b)         What is difference between a pulsed radar and MTI? A3 GHz pulsed radar (MTI has a maximum unamoigous range of 150km. Calculate the first two blind speeds.

8.         Write short notes on any four

a)         Monopulse radar

b)         Colour sub-carrier

c)         Silicon diode array

d)         False alarm

f)          Flicker

g)         Blanking and Synchronising pulses.




1          (a)        Explain the ioperation of the Reflex Klystron oscillatorwith the

applegate diagram.

(b)        Why is the transit time so important in this device ?

(c)        Derive the expression for the electronic admittance of a Reflex Klyastron.

2.         (a)        What are the major differences between the TWT and Klystron ?

Discuss the performance of TWT amplifier.

(b)        Describe the principle or operation of a TWT amplifier alongwith the analysis of Electron field interaction.

3.         (a)        Give the constructional features of a multicavity magnetron and

describe its mechanism of oscillatioin.

(b)        What do you mean by transferred electron effect ? Describe a Gunn device and discuss about the operation.

4.         (a)        Find an expression for the line impedance and characteristic

impedance of a transmission line.

(b)        An open-wire transmission line has R = 5W /m

L = 5.2 x 10-8H/m, G = 6.2 x 10-3 mho/m,

C = 2.13 x 10-10F/m

The signal frequency is 4 GHZ.



(i)                  The characteristic impedance of the line.

(ii)                The propagation constant of the wave along the line.

(iii)               The normalized impedance of a load.

(iv)              The reflection coefficient at the load.

5.         (a)        Derive the expression for the fields in a rectangular waveguide for TE

waves and the expression for f0, b, l,  u  taking into account that air conducting walls.

(b)        A rectangular waveguide with air dielectric carries TE10 mode at 9376 MHz. The internal dimension of the waveguide are icm and 22.8 cm. Evaluate the guide wavelength and intrinsic impendence.

6.         (a)        What is an isolator ? Explain with a neat diagram.

            (b)        Explain in the following :

(i)         coupling probe

(ii)        coupling loops

(c)        What is an attenuator ? Explain the characteristics of wave guide attenuator.

7.         (a)        Describe the method for measurement of Radiation pattern and gain of

an antenna.

(b)        With a block diagram explain the operation of a microwave receiver

(c)        Why TEM wave can’t propagate chrough a rectangular wave guide ?


1.         (a)        Give an overview of analog and digital data transmission.

(b)        Explain the properties of various types of transmission media. Discuss their advantages and disadvantages with regard to application.

2.         (a)        Elucidate the data encoding techniques. Explain some of the encoding

formats. Discuss their typical features and performances.

(b)        Through public telephone system give an example of digital and analog transmission system.

3.         Draw the block diagram of a PCM system and explain. Taking the an example of an arbitary analog time domain signal discuss the process of digitacation. What do you mean by quantization error ? Show that the error is s2/ 12; where ‘s’ is the step size.

4.         (a)        Write notes on the following  ;

            (i)         Asynchronous and synchronous transmission

            (ii)        Full and Half duplex.

(b)        Why is a stop-and-wait protocol not suitable for satellite channels ? Explain

how a sliding window protocol overcomes this problem ? Distinguish between a go-back-n sliding window protocol from the selective repeat protocol.

5.         (a)        What do you mean by multiplexing. Explain FDM and TDM.

(b)        What is congestion ? Why it occurs and how to avoid it.

(c)        Distinguish between circuit switching and switching network ?

6.         (a)        Describe the architecture of a computer network with reference to the

OSI reference model.

(b)        Explain the meaning of control signaling.

7.         Discuss the following :

(a)        Protocol and architecture

(b)        ATM logical connection

(c)        Routing

(d)        Packet switching

8.         Write short notes on any four

(a)        LAN

(b)        TCP / IP protocol

(c)        Modems]

(d)        ASK, FSK, PSK

(e)        Sliding window flow control

(f)         Ethernet

(g)        Frame relay.



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