Isro Electronics Interview Questions 3h534f

Candidate 1 In isro there are around 8 scientists in interview -----interview starts with ur final year project they will ask u to explain project nd if required they will ask u to go on black board---den they will ask ur fav subjects mostly qus will be related to those subjects only but some will be random qus from any subject-----like in my case i told logic ckt,emt,microwave---qus were propogation delay of ttl loogic family,how synchronous counter faster than asynchronous counter,name of diff types of adc nd dacs which u have read,why dual slope is called dual slope adc and what is its speciality in comparison to other----from one student qus was on digital voltmeter also---den from emt diff between mode and polarisation which is medium property and which is wave property,to which dimension electric field line are perpendicular broader or narrower dimension in TE01 mode,explain poynting theorm and write its expression also,in microwave only range of microwave frequency,then ask me to draw any minimum bandwidth amplifier and its frequency response also--it was tuned amplifier but i did not recollect at that time and thought it would be among cc,cb,ce--den ask dat whether i can ans qus from electrical engineering subject or not---i said i did not becoz i read that subject in 2nd year,den they ask me to draw any AM wave and ed it through dispersion medium and show its effect on AM wave---they ask me whether i know beta omega relation in dispersion medium or not i said no and den they stop the interview— Candidate 2 It took around 20- 25 minutes. The is having 9 or 10 scientist. The senior scientist sitting at the middle asked most of the questions. We will be standing in front of a board where we have to draw diagrams if asked. I some of the questions. Shamsudheen, which subject you have prepared? -communication engineering. He asked many questions from transmission line characteristics, stub matching, wave guides, etc. I said what these things are. But he asked to tell basic concepts like why there is only TE or TM mode in wave guide and not TEM. I know very little about transmission lines. I asked him to change the topic. Then they asked questions generally from electronics basics like > what is modulation? > different kinds of modulation > draw the circuit if demodulator > what is the output of not gate for sine wave input? > how to shift a sine wave up or down? > different kinds of modulation They asked about my project.I did my project in Wipro technologies, Basically it is a java based application to control multi-functional printer networks. Maybe because, it is in java they didn’t ask questions from the project. Also they asked if I have any other offer and in which company. I said bosch. Candidate 3 The senior scientist sitting at the middle asked for the subjects i prepared most. I told Radars and Satellite communications. He fired few questions on radars and other 9 asked one or two questions, that's all. I was mostly asked from Satellite communications. I'm keeping my fingers crossed!!!!!!!!! I just have a good feeling about this man, i just hope i make it into ISRO. Do you want more on the interview. Scroll down. I enter the room, the main scientist calls my name and asks me to take a seat. Its a long oval shaped table with me at other end and nine scientists at other end. First he asked me about the gap after my graduation. I told him i had an offer with Infosys but didn't like the software domain. He smiles. Then he said, what did you do for a year. I said, i prepared for GATE but couldn't attend it. Next, Scientist in the middle: which subjects you prepared most?

Me: My favourite subjects are Radars and Satellite communications. Scientist in the middle: Out of the two, which do you prefer. Me: Pause, Radars. http://www.TowardsJob.com Scientist in the middle: What is meant by RADAR. Me: Radio Detection and Ranging. Scientist in the middle: What principle does it work on? Me: Doppler effect. (I explain in detail about it) Scientist in the middle: No, doppler effect can be used in RADAR but what principle does it work on. Me: RADAR works on the principle of finding the position and velocity of target amidst clutter. Scientist in the middle: What is clutter? Me: Clutter is disturbance caused by land, sea, and sky clutter. Scientist in the middle: What kind of signals can be used in RADAR. Me: Both continuous waves and pulsed waves. Scientist in the middle: If we use continuous waves, then receiver will run into saturation. Me: We can use separate transmitter and receiver rather than a duplexer. He doesn't seem impressed. Next, he request scientist on his right, Mr. Ashok if i to ask me some questions. He asks me wavelength of 300MHz wave, i request for paper. They say its available on the table. The scientist in the middle says you don't need to calculate it. I laugh and still scratch on the paper and work it out as 1 metre. Stupid of me. I could have just answered normally. The next scientist on the right asks me some questions on satellite communications. Scientist: What is the main difference between satellite and cellular communications. Me: Satellite is mainly a repeater in the sky, which is basically used for long distance communications where are cellular communications use local networks to work. Scientist: Can't we use satellite for short distance then? Me: We can. Scientist: Then what is the basic difference between satellite and cellular communications. Me: I stick on the aswer that satellites are used to carry long distance traffic. He drops the

question. Scientist: What distance do the satellites use. Me: I mistake it for delay and say that it takes about 270mS. Scientist: No, the range? Me: 36000 kilometers. He seems satisfied. Scientist: Can we use LEO satellites for communications? Me: Yes. Scientist: Give me an example. Me: Iridium. He nods his head in agreement. Now, the focus on to the next scientist on his right. Scientist: You might have heard about modulation schemes. Why are there so many modulation schemes like BPSK,QPSK, QAM etc. Me: It depends upon the application. Scientist: Which is used in satellite comm. Me: BPSK is most widely used in satellite comm. Scientist: Can't we use others? What is the difference between 8QPSK and other schemes. Me: 8QPSK uses only 8 signal points in signal space while others use variable signal points.