# In a baseband communications link, frequencies up to 3500 Hz are used for signaling using a raised cosine pulse with 75% excess bandwidth and for no inter-symbol interference,the maximum possible signaling rate in symbols per seconds is

1.  1750

2.  2625

3.  4000

4.  5250

4

4000

Explanation :
No Explanation available for this question

# The power spectral density of a real process X(t) for positive frequencies is shown below the values of E[X2(t)] and [E[X(t)]], respectively are

1.  6000/π,0

2.  6400/π,0

3.  6400/π,20/(π√2)

4.  6000/π,20/(π√2)

4

6400/π,0

Explanation :
No Explanation available for this question

# The current I through the base of a silicon npn transistor is 1+0.1cos(10000πt) mA. At 300k, the rπ in the small signal model of transistor is

1.  250

2.  27.5

3.  25 W

4.  22.5 W

4

25 W

Explanation :
No Explanation available for this question

# T he source of a silicon (ni = 1010 per cm3) n-channel MOS transistor has an area of 1 sq μm and adepth of 1 μm. If the dopant density in the source is 1019/cm3, the number of holes in the source region with the above volume is approximatel

1.  107

2.  100

3.  10

4.  0

4

0

Explanation :
No Explanation available for this question

# A transmission line with a characteristic impedance of 100 Ω is used to match a 50 Ω section to a 200 Ω section. If the matching is to be done both at 429 MHz and 1 GHz, the length of the transmission line can be approximately

1.  82.5 cm

2.  1.05 m

3.  1.58 m

4.  1.75 m

4

1.05 m

Explanation :
No Explanation available for this question

# T he feedback system shown below oscillates at 2 rad/s when

1.  K = 2 and a = 0.75

2.  K = 3 and a = 0.75

3.  K = 4 and a = 0.5

4.  K = 2 and a = 0.5

4

K = 2 and a = 0.75

Explanation :
No Explanation available for this question

# A  fair  coin  is  tossed  till  a  head  appears  for  the  first  time.  The  probability  that  the  number  of required tosses is odd, is

1.   1/3

2.  1/2

3.  2/3

4.  3/4

4

2/3

Explanation :
No Explanation available for this question

# A BPSK scheme operating over an AWGN channel with noise power spectral density of N0/2 ,uses equiprobable signals  S1(t)=√2E/T sin(ωcθ)   S2(t)=-  - √2E/T sin(ωcθ)    over the symbol interval (0, T). If the local oscillator in a coherent receiver is ahead in phase by 450 with respect to the received signal, the probability of error in the resulting system is

1.

2.

3.

4.

4 Explanation :
No Explanation available for this question

# T he input x(t) and output y(t) of a system are related as   The system is

1.  time-invariant and stable

2.  stable and not time-invariant

3.  time-invariant and not stable

4.  not time-invariant and not stable

4

stable and not time-invariant

Explanation :
No Explanation available for this question

1.   ¼

2.  ½

3.  1

4.  2

4