# Consider a system shown in the Figure. Let X(f) and Y(f) denote the Fourier transforms of x(t) and y(t) respectively. The ideal HPF has the cutoff frequency frequency 10 kHz he positive frequencies where Y(f) has spectral peaks are

1.  1 kHz and 24 kHz

2.  2 kHz and 24 kHz

3.  1 kHz and 14 kHz

4.  2 kHz and 14 kHz

4

2 kHz and 24 kHz

Explanation :
No Explanation available for this question

# In  an  abrupt  p-n  junction,  the  doping  concentrations  on p-side  and  n-side  are NA  =  9  x 1016/cm3 and ND = 1 x 1016/cm3 respectively. The p-n junction is reverse biased and the total depletion width is 3 μm. The depletion width on the p-side is

1.  2.7 μm

2.  0.3 μm

3.    2.25 μm

4.  0.75 μm

4

0.3 μm

Explanation :
No Explanation available for this question

# A source produces binary data at the rate of 10 kbps. The binary symbols are represented as shown in the figure given below The  source  output  is  transmitted  using  two  modulation  schemes,  namely  Binary  PSK (BPSK)  and Quadrature PSK  (QPSK).  Let B1  and B2  be  the  bandwidth  requirements  of BPSK  and  QPSK  respectively.  Assuming  that  the  bandwidth  of  the  above  rectangular pulses is 10 kHz, B1 and B2 are

1.  B1 = 20 kHz, B2 = 20 kHz

2.   B1 = 10 kHz, B2 = 20 kHz

3.   B1 = 20 kHz, B2 = 10 kHz

4.  B1 = 10 kHz, B2 = 10 kHz

4

B1 = 20 kHz, B2 = 10 kHz

Explanation :
No Explanation available for this question

# Consider a 300Ω quarter-wave long (at 1 GHz) transmission line as shown in the figure. It is connected to a 10 V, 50 sources at one end and is left open circuited at the other end. The magnitude of the voltage at the open circuit end of the line is

1.  10 V

2.  5 V

3.  60 V

4.  60/7 V

4

60/7 V

Explanation :
No Explanation available for this question

# The  resistivity  of  a  uniformly  doped  n-type  silicon  sample  is  0.5  Ω-cm.  If  the  electron mobility (μn) is 1250 cm2/V-sec and the charge of an electron is 1.6 x 10-19 Coulomb,  the donor impurity concentration (ND) in the sample is

1.  2 x 1016 /cm3

2.  1 x 1016 /cm3

3.  2.5 x 1015 /cm3

4.  2 x 1015 /cm3

4

1 x 1016 /cm3

Explanation :
No Explanation available for this question

# Consider an abrupt p-junction. Let Vbi be  the built-in potential of  this  junction and VR  be the applied reverse bias. If the junction capacitance (Cj) is 1 pF for Vbi  + VR = 1V, then for Vbi + VR = 4V, Cj  will be

1.  4 pF

2.  2 pF

3.  0.25 pF

4.  0.5 pF

4

0.5 pF

Explanation :
No Explanation available for this question

# Consider the following statements S1 and S2. S1 : The threshold voltage (VT) of a MOS capacitor decreases with increase in gate oxide thickness S2  : The  threshold voltage (VT) of a MOS capacitor decreases with  increase  in substrate doping concentration. Which one of the following is correct

1.  S1 is FALSE and S2 is TRUE

2.  both S1 and S2 are TRUE

3.  S1 is TRUE and S2 is FALSE

4.  both S1 and S2 are FALSE

4

S1 is FALSE and S2 is TRUE

Explanation :
No Explanation available for this question

# The  drain  of  an  n-channel  MOSFET  is  shorted  to  the  gate  so  that  VGS  =  VDS.  The threshold voltage  (VT) of MOSFET  is 1V.  If  the drain current  (ID)  is 1 mA  for VGS  =  2V, then for VGS = 3V, ID is

1.  2 mA

2.  3 mA

3.  9 mA

4.  4 mA

4

4 mA

Explanation :
No Explanation available for this question

# A  bipolar  transistor  is  operating  in  the  active  region  with  a  collector  current  of  1  mA.Assuming  that  the  β of  the  transistor  is 100 and  the  thermal  voltage  (V T)  is  25 mV,  the transconductance  (gm)  and  the  input  resistance  (rπ)  of  the  transistor  in  the  common emitter configuration, are

1.  gm = 25 mA /V and rπ = 15.625 k

2.  gm = 40 mA /V and rπ = 4.0 k?

3.  gm = 25 mA /V and rπ = 2.5 k?

4.  gm = 40 mA /V and rπ = 2.5 k?

4

gm = 40 mA /V and rπ = 2.5 k?

Explanation :
No Explanation available for this question

1.  1.416 eV

2.  0.886 eV

3.  0.854 eV

4.  0.706 eV

4