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Sample Topics

Analog Circuits

Analog circuits involve the use of analog signals, which vary continuously with time. The study of analog circuits involves the operation, analysis and applications of analog circuits, and their troubleshooting concepts. Analog circuits include diodes, transistors, operational amplifiers. The applications of analog circuits include Filters, Amplifiers, Oscillators and Timers, Voltage Regulators, communication and data conversion circuits.
Sample Questions:

Q1. Draw a basic full bridge rectifier schematic

Q2. For Si with ND 1016 cm-3, how hot does the Si need to be for the intrinsic level to be the same as the doping level? (ignore the temperature dependence of Nc, Nv) Draw a log (n) vs 1/T plot. Compare with GaAs and Ge, would the temperatures be higher or lower (why?) 

Q3. Consider a receiver with the following specifications: Ap=80, NFtot= 3.4, B=100khz, 01P3-20 dBm, OP18-10 dBm.

The minimum required SNR is 15 dB for acceptable signal. Find the spurious-free dynamic range (SFDR) for the receiver, including the minimum SNR requirement, as defined in class.

MATLAB Software

MATLAB is an acronym for Matrix Laboratory. It is a fourth-generation programming language with huge command library of inbuilt functions.  From algorithm development and analyzing data to designing models and real-time simulations, MATLAB can realize all the user’s ideas through its Graphical User Interface (GUI) and SIMULINK packages. MATLAB finds it application in control systems, Analysis and design of power systems, Image and signal processing, robotics, and in  financial computations.
Sample Questions: 

Q1. MATLAB exercise: Consider a periodic signal composed of three sinusoids of frequencies 700Hz, 1300Hz, and 2000Hz. Sample this signal at 3000Hz. After sampling, apply a low pass filter with a cut-off frequency of 1500Hz. What will be the components of the output signal? Use MATLAB to do the filtering. Show the original periodic signal and the recovered signal after filtering as plots in MATLAB

 Q2. Write a MATLAB function that will take as inputs the values of the parameters of theequivalent circuit model of the synchronous machine as well as the information about the load on the machine and will produce voltage regulation and efficiency.

Power Electronics and Applications

Power Electronics deals with the study of switching electronic circuits for the control and conversion of electrical energy. The switching circuits use power devices like diodes, power transistors and thyristors. The power-electronic circuits include rectifiers, inverters, choppers, cyclo-converters, voltage regulators and their applications in starting and control of electrical machines. 
Sample Questions:

Q1. Power Electronics:


Using PLECS:


Assume 100 kHz switching frequency for all the following problem


There is a 2 kW single phase full bridge inverter with 400 V input dc and 240 V output ac rms voltage with 60 Hz fundamental frequency, assume there is an output LC filter of the inverter which is 100 uH and 10 uF. And the output load resistance is 24 Ohm. Simulate the inverter at the full power with the corresponding input and output voltage. Calculate the modulation index M , Provide schematics , two fundamental cycle of output voltage , two fundamental cycle of inductor current


 

Analog Communications

Communication stands for sharing/exchange of information. Analog communication deals with transmission and reception of continuous time domain signal. It includes generation of signal, modulation (AM, FM, PCM etc.), multiplexing, de-multiplexing and demodulation. It deals with transmitters, receivers (radio receivers, super-heterodyne receiver), and studies the noise encountered (thermal shot etc.) during analog signal communication.
Sample Questions:

5.1-7 Consider a bandlimited signal gi(t) whose Fourier transform is G 1 (f)-5. Δ(f/800) (a) If gi(1) is uniformly sampled at the rate of fs 400 Hz, show the resulting spectrum of the (b) If we attempt to reconstruct gi (t) from the samples in Part (a), what will be the recovered (e) Determine another analog signal G2 in frequency domain such that its samples at ideally sampled signal. analog signal in both time and frequency domains? 400 Hz will lead to the same spectrum after sampling as in Part (a). (d) Confirm the results of (c) by comparing the two sample sequences in time domain

Electrical Machines

An electrical machine is a device that converts mechanical energy to electrical energy and vice-versa or transfers electrical energy from one circuit to the other.  This subject covers the principle of operation, construction, working, testing and applications of the electrical machines such as motors, generators and transformers. Electrical machines can be classified into DC and single-phase or three-phase AC machines. 
 
Sample Questions:

Elementary ac machine 2-pole, 2-phase machine

(a) For a 2-pole, 2-phase doubly fed induction machine, show the physical layout of the machine and the winding arrangement. Give the stator inductance matrix. Give the stator and rotor inductances in terms of self and mutual inductances and the complete machine inductance matrix. Give the flux linkages in terms of inductances and winding currents.

(b) Repeat for a 2-pole, 3-phase salient-pole synchronous machine. Explain the differences with the induction machine.

Electromagnetic Theory

Electromagnetics is basically the combined study of electric and magnetic fields. It deals with the learning of the electromagnetic fields which are generated by time varying charge distributions. It also deals with the principles of electromagnetism. It includes Maxwell’s equations and basic laws like Faraday’s law, Lorentz law, etc. and their applications. The theory also explains the concept of transmission lines, waveguides and antennas.
Sample Questions:

A Class C amplifier has a load impedance of 600 ohms.Suppose this is to be connected to a Collins Coupler so that it connects to an antenna of 75 ohms. Assume a Q of 12 Calculate Xc, Xc, and X.Ques

Draw your final circuit.

Microcontrollers/Microprocessors

Microprocessor is the heart of computer as it is an integrated circuit containing all the functions of central processor (CPU), whereas Microcontroller is a computer on an IC. A microcontroller is a combination of processor, memory, and Input/outputs units fabricated on a single chip. Microprocessor is general purpose which could be programmed for any application, whereas microcontrollers is designed for specific application.
Sample Questions:

1) Given DO, write instructions to do the following: a. Set bits 113, 21 in D0 b. Reset bits 2,8,30 in DO

2) What are the differences between macro and subroutines and when are macros superior?

3) Represent 3697 in IEEE format

4) Hand assemble the following code Note: learn how to write displacement to an instruction written before the branch instruction which requires using the second complements.

5) List the micro step instructions for: 123(a0.al), 60(a2) 6) Discuss the execution of the rte instruction

Microelectronic and Integrated Circuits

Microelectronics deals with the assembly of electronics components (active such as transistor (BJT, FET, CMOS), diodes, and passive such as resistors, capacitor and inductor) on a single very small size chip called as microchip.  Integrated Circuit also called IC is designed to perform specific task such as oscillator, timer, microprocessor. Microelectronic and Integrated Circuits covers topics from fabrication of electronic component to their assembling on a small size silicon IC called microchip.
Sample Questions:

Draw a 4×4 cell array of NAND flash memory with selection transistors on both sides of the string of floating gate cells. Considering the operating principles of NAND flash memory, determine the bias voltages of selected and unselected wordlines, bit lines, and selection transistors. In programming step, you have to program 1~3 bits among 4 bits. Assume that the tunneling requires 12V across the tunneling oxide and CC/CT = 1.5. CC and CT are capacitance of floating gate toward control gate and substrate, respectively.