 Sorry I don't remember any q. from aptitude but one
which is
one pump can fill a tank in 12 & other in 15 minute.both 2 opend for 5
minute. now one more pump is opend which alone can empty the tank in 6
minute. In what time the tank will empty.
50% q's on compre given a passage u have to anser some q.

Now most interesting part that is DSP part.I think telecom people should
opt for this section as it was very basic & every one has done the same
in his BE.Anyway,u will get 5 minute to decide which section u have to
choose. So there were 20 q's.
1). & 2) some permutation & combination type of things
very boring for me. I think hemant from IISc will soon send these 2 q's.
3)how many quad nand IC's required to implement one exor.
ans- 1 (as 4 nand required for one exor).
4) D flip flop with Qbar connected to D i/p (means a T-filp flop)
   what does it do.
ans- devide i/p freq ( ofcourse by-2)
5) , 6)  each on C lan. but very easy. Hemant will send these also
soon. in q-6 in a for loop semicolon is missing & ans is 3.
7) 2 no's 10 & 20 r and(GATE). o/p will be
ans- 0.
Now DSP starts...(may not be in order but q r exact)
8) fourier series of a discrete periodic signal of infinite duration
will be.. ( very confusing as period is infinte or sequence) Anyway,we
assume the sequence as if piriod is infinite the DFT comes into picture.
so ans is- discrete periodic signal of infinite duration
9) 1+4z^-1 , the ZT will converge for
ans- |z|>0 (entire z plane as it's FIR sequence)
10) ext(-a*t) is.
ans- I think neither energy nor power( as it has inf energy for -ve t &
     it's not periodic to be a power signal. pl. check it)
11).3 symbol A,B &  C with probabilities .53 , .4 & .07, huffman code is
used what binary value may be assighned to Symbol A)
ans- 0.
12) y(n) = a*y(n-1)+x(n). what should be a for system to be stable.
ans a < 1.
13) a mp with 10 data line. 10 address line & 8 control lines.
how many memories can be addressed.
ans-1Kbyte (2^10 only address lines).
14) given a contineous periodic signal freq fm, after sampling with freq
fs discrete sigal will be.
ans - I think it depend on both fm & fs.(my approch is cos or sin or
ext(j*2*pi*fm*n*T)=ext(j*2*pi*fm*n/fs)=ext(j*2*pi*fm*(n+N)/fs). N is
period. so 2*pi*(fm/fs)*N = 2*pi*k. So fm/fs must be rational. & hence
should depend on both. ( anyway, check it & clarify).

*******************************
Some more Questions
******************************

1. There are 5 balls and 3 slots. In how many ways can you fill the
slots?
Ans: 5P3.
2. for (i=0; i*2<6 ;i++);
      {
      printf("i=%d ",i);
      }

Ans: i=3

3. Which of the following signals is periodic?
(a) sin(3*n)
(b) sin(3*pi*n)
(c)
(d)

4. A frequency f1 ; when signal sampled with fs; will get mapped to what
frequency in discrete domain?
Ans: 2*pi*f1/fs


Regarding the interview.

They ask very basic questions. Questions DO repeat ;so keep track of the
person giving the interview before you.
Some typical questions:

1. How will you construct 4 input AND gate using two input AND gates. By
how many ways?

2. You are given a circuit which is a four input ANd gate formed out of
one of the ways in question 1. How will u know exactly which way it's
constructed?
Ans: Propagation delay and all.

3. DSP: Impulse response given. Build the digital filter.
Ans: Take z transform and take inverse z transform to get the difference
equation.

4. Questions regarding z-plane and BIBO stability etc.

5. RC circuit step response. etc wveforms
