Electronics and Communication Engineering (EC) 2013 GATE Paper (Set D) without solution | GATE Past Year Papers for Practice (All Branches)

 Page 1


 
 
 
 
 
 
 
SESSION - 4 
 
 
 
 
 
 
 
 
Page 2


 
 
 
 
 
 
 
SESSION - 4 
 
 
 
 
 
 
 
 
2013                                                                                                                           Question Booklet Code                                                                           
 
EC-D 
 
1/24
EC : ELECTRONICS AND COMMUNICATION ENGINEERING 
 
Duration: Three Hours                       Maximum Marks: 100 
Read the following instructions carefully. 
 
1. Do not open the seal of the Question Booklet until you are asked to do so by the invigilator. 
2. Take out the Optical Response Sheet (ORS) from this Question Booklet without breaking the seal 
and read the instructions printed on the ORS carefully. If you find that either: 
a. The Question Booklet Code printed at the right hand top corner of this page does not match with 
the Question Booklet Code at the right hand top corner of the ORS or 
b. The Question Paper Code preceding the Registration number on the ORS is not EC,  
            then exchange the booklet immediately with a new sealed Question Booklet.  
3. On the right hand side of the ORS, using ONLY a black ink ballpoint pen, (i) darken the appropriate 
bubble under each digit of your registration number and (ii) write your registration number, your 
name and name of the examination centre and put your signature at the specified location.  
4. This Question Booklet contains 24 pages including blank pages for rough work. After you are 
permitted to open the seal, check all pages and report discrepancies, if any, to the invigilator. 
5. There are a total of 65 questions carrying 100 marks. All these questions are of objective type. Each 
question has only one correct answer. Questions must be answered on the left hand side of the ORS 
by darkening the appropriate bubble (marked A, B, C, D) using ONLY a black ink ballpoint pen 
against the question number. For each question darken the bubble of the correct answer. More 
than one answer bubbled against a question will be treated as an incorrect response. 
6. Since bubbles darkened by the black ink ballpoint pen cannot be erased, candidates should darken the 
bubbles in the ORS very carefully. 
7. Questions Q.1 – Q.25 carry 1 mark each. Questions Q.26 – Q.55 carry 2 marks each. The 2 marks 
questions include two pairs of common data questions and two pairs of linked answer questions. The 
answer to the second question of the linked answer questions depends on the answer to the first 
question of the pair. If the first question in the linked pair is wrongly answered or is not attempted, 
then the answer to the second question in the pair will not be evaluated. 
8. Questions Q.56 – Q.65 belong to General Aptitude (GA) section and carry a total of 15 marks. 
Questions Q.56 – Q.60 carry 1 mark each, and questions Q.61 – Q.65 carry 2 marks each. 
9. Questions not attempted will result in zero mark and wrong answers will result in NEGATIVE 
marks.  For all 1 mark questions, ? mark will be deducted for each wrong answer. For all 2 marks 
questions, ? mark will be deducted for each wrong answer.  However, in the case of the linked 
answer question pair, there will be negative marks only for wrong answer to the first question and no 
negative marks for wrong answer to the second question.  
10. Calculator is allowed whereas charts, graph sheets or tables are NOT allowed in the examination hall. 
11. Rough work can be done on the Question Booklet itself. Blank pages are provided at the end of the 
Question Booklet for rough work. 
12. Before the start of the examination, write your name and registration number in the space provided 
below using a black ink ballpoint pen. 
Name 
 
 
Registration Number 
EC 
       
 
 
D 
Page 3


 
 
 
 
 
 
 
SESSION - 4 
 
 
 
 
 
 
 
 
2013                                                                                                                           Question Booklet Code                                                                           
 
EC-D 
 
1/24
EC : ELECTRONICS AND COMMUNICATION ENGINEERING 
 
Duration: Three Hours                       Maximum Marks: 100 
Read the following instructions carefully. 
 
1. Do not open the seal of the Question Booklet until you are asked to do so by the invigilator. 
2. Take out the Optical Response Sheet (ORS) from this Question Booklet without breaking the seal 
and read the instructions printed on the ORS carefully. If you find that either: 
a. The Question Booklet Code printed at the right hand top corner of this page does not match with 
the Question Booklet Code at the right hand top corner of the ORS or 
b. The Question Paper Code preceding the Registration number on the ORS is not EC,  
            then exchange the booklet immediately with a new sealed Question Booklet.  
3. On the right hand side of the ORS, using ONLY a black ink ballpoint pen, (i) darken the appropriate 
bubble under each digit of your registration number and (ii) write your registration number, your 
name and name of the examination centre and put your signature at the specified location.  
4. This Question Booklet contains 24 pages including blank pages for rough work. After you are 
permitted to open the seal, check all pages and report discrepancies, if any, to the invigilator. 
5. There are a total of 65 questions carrying 100 marks. All these questions are of objective type. Each 
question has only one correct answer. Questions must be answered on the left hand side of the ORS 
by darkening the appropriate bubble (marked A, B, C, D) using ONLY a black ink ballpoint pen 
against the question number. For each question darken the bubble of the correct answer. More 
than one answer bubbled against a question will be treated as an incorrect response. 
6. Since bubbles darkened by the black ink ballpoint pen cannot be erased, candidates should darken the 
bubbles in the ORS very carefully. 
7. Questions Q.1 – Q.25 carry 1 mark each. Questions Q.26 – Q.55 carry 2 marks each. The 2 marks 
questions include two pairs of common data questions and two pairs of linked answer questions. The 
answer to the second question of the linked answer questions depends on the answer to the first 
question of the pair. If the first question in the linked pair is wrongly answered or is not attempted, 
then the answer to the second question in the pair will not be evaluated. 
8. Questions Q.56 – Q.65 belong to General Aptitude (GA) section and carry a total of 15 marks. 
Questions Q.56 – Q.60 carry 1 mark each, and questions Q.61 – Q.65 carry 2 marks each. 
9. Questions not attempted will result in zero mark and wrong answers will result in NEGATIVE 
marks.  For all 1 mark questions, ? mark will be deducted for each wrong answer. For all 2 marks 
questions, ? mark will be deducted for each wrong answer.  However, in the case of the linked 
answer question pair, there will be negative marks only for wrong answer to the first question and no 
negative marks for wrong answer to the second question.  
10. Calculator is allowed whereas charts, graph sheets or tables are NOT allowed in the examination hall. 
11. Rough work can be done on the Question Booklet itself. Blank pages are provided at the end of the 
Question Booklet for rough work. 
12. Before the start of the examination, write your name and registration number in the space provided 
below using a black ink ballpoint pen. 
Name 
 
 
Registration Number 
EC 
       
 
 
D 
2013                                                                                                                             ELECTRONICS & COMMN. ENGG.  -  EC                                                                                                                       
 
EC-D 2/24
Q.1 to Q.25 carry one mark each. 
Q.1 Let 
2
p t
( ) g t e
- = , and ( ) h t is a filter matched to ( ) g t . If ( ) g t is applied as input to ( ) h t , then 
the Fourier transform of the output is 
(A) 
2
f
e
p - (B) 
2
/2 f
e
p - 
(C)  
| | f
e
p - 
(D)  
2
2 f
e
p - 
 
Q.2 The return loss of a device is found to be 20 dB. The voltage standing wave ratio (VSWR)  and 
magnitude of reflection coefficient are respectively 
(A) 1.22 and 0.1 (B) 0.81 and 0.1 (C) - 1.22 and 0.1 (D) 2.44 and 0.2 
 
Q.3 
A source  ( ) cos100
s
v t V t p =
 
has an internal impedance of (4 + j3) ?. If a purely resistive load  
connected to this source has to extract the maximum power out of the source, its value in ? should be 
(A) 3 (B) 4 (C)  5 (D) 7 
 
Q.4 The transfer function 
) (
) (
1
2
s V
s V
of the circuit shown below is 
 
 
 
 
(A) 
1
1 5 . 0
+
+
s
s
 (B) 
2
6 3
+
+
s
s
  
(C) 
1
2
+
+
s
s
 (D) 
2
1
+
+
s
s
 
 
Q.5 Assuming zero initial condition, the response ) (t y of the system given below to a unit step input  
) (t u is 
 
(A) ) (t u (B)  ) (t u t 
(C)  ) (
2
2
t u
t
 (D) ) (t u e
t - 
 
Q.6 
A polynomial 
4 3 2
4 3 2 1 0
( ) f x a x a x a x a x a = + + + - 
with all coefficients positive has  
(A) no real roots (B) no negative real root 
(C) odd number of real roots 
(D) at least one positive and one negative real root 
Page 4


 
 
 
 
 
 
 
SESSION - 4 
 
 
 
 
 
 
 
 
2013                                                                                                                           Question Booklet Code                                                                           
 
EC-D 
 
1/24
EC : ELECTRONICS AND COMMUNICATION ENGINEERING 
 
Duration: Three Hours                       Maximum Marks: 100 
Read the following instructions carefully. 
 
1. Do not open the seal of the Question Booklet until you are asked to do so by the invigilator. 
2. Take out the Optical Response Sheet (ORS) from this Question Booklet without breaking the seal 
and read the instructions printed on the ORS carefully. If you find that either: 
a. The Question Booklet Code printed at the right hand top corner of this page does not match with 
the Question Booklet Code at the right hand top corner of the ORS or 
b. The Question Paper Code preceding the Registration number on the ORS is not EC,  
            then exchange the booklet immediately with a new sealed Question Booklet.  
3. On the right hand side of the ORS, using ONLY a black ink ballpoint pen, (i) darken the appropriate 
bubble under each digit of your registration number and (ii) write your registration number, your 
name and name of the examination centre and put your signature at the specified location.  
4. This Question Booklet contains 24 pages including blank pages for rough work. After you are 
permitted to open the seal, check all pages and report discrepancies, if any, to the invigilator. 
5. There are a total of 65 questions carrying 100 marks. All these questions are of objective type. Each 
question has only one correct answer. Questions must be answered on the left hand side of the ORS 
by darkening the appropriate bubble (marked A, B, C, D) using ONLY a black ink ballpoint pen 
against the question number. For each question darken the bubble of the correct answer. More 
than one answer bubbled against a question will be treated as an incorrect response. 
6. Since bubbles darkened by the black ink ballpoint pen cannot be erased, candidates should darken the 
bubbles in the ORS very carefully. 
7. Questions Q.1 – Q.25 carry 1 mark each. Questions Q.26 – Q.55 carry 2 marks each. The 2 marks 
questions include two pairs of common data questions and two pairs of linked answer questions. The 
answer to the second question of the linked answer questions depends on the answer to the first 
question of the pair. If the first question in the linked pair is wrongly answered or is not attempted, 
then the answer to the second question in the pair will not be evaluated. 
8. Questions Q.56 – Q.65 belong to General Aptitude (GA) section and carry a total of 15 marks. 
Questions Q.56 – Q.60 carry 1 mark each, and questions Q.61 – Q.65 carry 2 marks each. 
9. Questions not attempted will result in zero mark and wrong answers will result in NEGATIVE 
marks.  For all 1 mark questions, ? mark will be deducted for each wrong answer. For all 2 marks 
questions, ? mark will be deducted for each wrong answer.  However, in the case of the linked 
answer question pair, there will be negative marks only for wrong answer to the first question and no 
negative marks for wrong answer to the second question.  
10. Calculator is allowed whereas charts, graph sheets or tables are NOT allowed in the examination hall. 
11. Rough work can be done on the Question Booklet itself. Blank pages are provided at the end of the 
Question Booklet for rough work. 
12. Before the start of the examination, write your name and registration number in the space provided 
below using a black ink ballpoint pen. 
Name 
 
 
Registration Number 
EC 
       
 
 
D 
2013                                                                                                                             ELECTRONICS & COMMN. ENGG.  -  EC                                                                                                                       
 
EC-D 2/24
Q.1 to Q.25 carry one mark each. 
Q.1 Let 
2
p t
( ) g t e
- = , and ( ) h t is a filter matched to ( ) g t . If ( ) g t is applied as input to ( ) h t , then 
the Fourier transform of the output is 
(A) 
2
f
e
p - (B) 
2
/2 f
e
p - 
(C)  
| | f
e
p - 
(D)  
2
2 f
e
p - 
 
Q.2 The return loss of a device is found to be 20 dB. The voltage standing wave ratio (VSWR)  and 
magnitude of reflection coefficient are respectively 
(A) 1.22 and 0.1 (B) 0.81 and 0.1 (C) - 1.22 and 0.1 (D) 2.44 and 0.2 
 
Q.3 
A source  ( ) cos100
s
v t V t p =
 
has an internal impedance of (4 + j3) ?. If a purely resistive load  
connected to this source has to extract the maximum power out of the source, its value in ? should be 
(A) 3 (B) 4 (C)  5 (D) 7 
 
Q.4 The transfer function 
) (
) (
1
2
s V
s V
of the circuit shown below is 
 
 
 
 
(A) 
1
1 5 . 0
+
+
s
s
 (B) 
2
6 3
+
+
s
s
  
(C) 
1
2
+
+
s
s
 (D) 
2
1
+
+
s
s
 
 
Q.5 Assuming zero initial condition, the response ) (t y of the system given below to a unit step input  
) (t u is 
 
(A) ) (t u (B)  ) (t u t 
(C)  ) (
2
2
t u
t
 (D) ) (t u e
t - 
 
Q.6 
A polynomial 
4 3 2
4 3 2 1 0
( ) f x a x a x a x a x a = + + + - 
with all coefficients positive has  
(A) no real roots (B) no negative real root 
(C) odd number of real roots 
(D) at least one positive and one negative real root 
2013                                                                                                                             ELECTRONICS & COMMN. ENGG.  -  EC                                                                                                                       
 
EC-D 3/24
 
Q.7 The minimum eigenvalue of the following matrix is 
3 5 2
5 12 7
2 7 5
? ?
? ?
? ?
? ?
? ?
 
(A) 0 
(B) 1 (C) 2   (D) 3   
 
Q.8 Which one of the following statements is NOT TRUE for a continuous time causal and stable  
LTI system? 
(A) All the poles of the system must lie on the left side of the  j?
 
axis. 
(B) Zeros of the system can lie anywhere  in the  s-plane. 
(C) All the poles must lie within 1 s = . 
(D) All the roots of the characteristic equation must be located on the left side of the
 
j? axis. 
 
Q.9 In a MOSFET operating in the saturation region, the channel length modulation effect causes 
(A)   an increase in the gate-source capacitance 
(B)   a decrease in the transconductance 
(C)   a decrease in the unity-gain cutoff frequency   
(D)   a decrease in the output resistance 
 
Q.10 A band-limited signal with a maximum frequency of 5 kHz is to be sampled. According to the 
sampling theorem, the sampling frequency which is not valid is  
(A) 5 kHz (B) 12 kHz (C) 15 kHz  (D)  20 kHz 
 
Q.11 In a voltage-voltage feedback as shown below, which one of the following statements is TRUE if 
the gain k is increased? 
 
 
 
(A) The input impedance increases and output impedance decreases. 
(B) The input impedance increases and output impedance also increases. 
(C) The input impedance decreases and output impedance also decreases. 
(D) The input impedance decreases and output impedance increases. 
Page 5


 
 
 
 
 
 
 
SESSION - 4 
 
 
 
 
 
 
 
 
2013                                                                                                                           Question Booklet Code                                                                           
 
EC-D 
 
1/24
EC : ELECTRONICS AND COMMUNICATION ENGINEERING 
 
Duration: Three Hours                       Maximum Marks: 100 
Read the following instructions carefully. 
 
1. Do not open the seal of the Question Booklet until you are asked to do so by the invigilator. 
2. Take out the Optical Response Sheet (ORS) from this Question Booklet without breaking the seal 
and read the instructions printed on the ORS carefully. If you find that either: 
a. The Question Booklet Code printed at the right hand top corner of this page does not match with 
the Question Booklet Code at the right hand top corner of the ORS or 
b. The Question Paper Code preceding the Registration number on the ORS is not EC,  
            then exchange the booklet immediately with a new sealed Question Booklet.  
3. On the right hand side of the ORS, using ONLY a black ink ballpoint pen, (i) darken the appropriate 
bubble under each digit of your registration number and (ii) write your registration number, your 
name and name of the examination centre and put your signature at the specified location.  
4. This Question Booklet contains 24 pages including blank pages for rough work. After you are 
permitted to open the seal, check all pages and report discrepancies, if any, to the invigilator. 
5. There are a total of 65 questions carrying 100 marks. All these questions are of objective type. Each 
question has only one correct answer. Questions must be answered on the left hand side of the ORS 
by darkening the appropriate bubble (marked A, B, C, D) using ONLY a black ink ballpoint pen 
against the question number. For each question darken the bubble of the correct answer. More 
than one answer bubbled against a question will be treated as an incorrect response. 
6. Since bubbles darkened by the black ink ballpoint pen cannot be erased, candidates should darken the 
bubbles in the ORS very carefully. 
7. Questions Q.1 – Q.25 carry 1 mark each. Questions Q.26 – Q.55 carry 2 marks each. The 2 marks 
questions include two pairs of common data questions and two pairs of linked answer questions. The 
answer to the second question of the linked answer questions depends on the answer to the first 
question of the pair. If the first question in the linked pair is wrongly answered or is not attempted, 
then the answer to the second question in the pair will not be evaluated. 
8. Questions Q.56 – Q.65 belong to General Aptitude (GA) section and carry a total of 15 marks. 
Questions Q.56 – Q.60 carry 1 mark each, and questions Q.61 – Q.65 carry 2 marks each. 
9. Questions not attempted will result in zero mark and wrong answers will result in NEGATIVE 
marks.  For all 1 mark questions, ? mark will be deducted for each wrong answer. For all 2 marks 
questions, ? mark will be deducted for each wrong answer.  However, in the case of the linked 
answer question pair, there will be negative marks only for wrong answer to the first question and no 
negative marks for wrong answer to the second question.  
10. Calculator is allowed whereas charts, graph sheets or tables are NOT allowed in the examination hall. 
11. Rough work can be done on the Question Booklet itself. Blank pages are provided at the end of the 
Question Booklet for rough work. 
12. Before the start of the examination, write your name and registration number in the space provided 
below using a black ink ballpoint pen. 
Name 
 
 
Registration Number 
EC 
       
 
 
D 
2013                                                                                                                             ELECTRONICS & COMMN. ENGG.  -  EC                                                                                                                       
 
EC-D 2/24
Q.1 to Q.25 carry one mark each. 
Q.1 Let 
2
p t
( ) g t e
- = , and ( ) h t is a filter matched to ( ) g t . If ( ) g t is applied as input to ( ) h t , then 
the Fourier transform of the output is 
(A) 
2
f
e
p - (B) 
2
/2 f
e
p - 
(C)  
| | f
e
p - 
(D)  
2
2 f
e
p - 
 
Q.2 The return loss of a device is found to be 20 dB. The voltage standing wave ratio (VSWR)  and 
magnitude of reflection coefficient are respectively 
(A) 1.22 and 0.1 (B) 0.81 and 0.1 (C) - 1.22 and 0.1 (D) 2.44 and 0.2 
 
Q.3 
A source  ( ) cos100
s
v t V t p =
 
has an internal impedance of (4 + j3) ?. If a purely resistive load  
connected to this source has to extract the maximum power out of the source, its value in ? should be 
(A) 3 (B) 4 (C)  5 (D) 7 
 
Q.4 The transfer function 
) (
) (
1
2
s V
s V
of the circuit shown below is 
 
 
 
 
(A) 
1
1 5 . 0
+
+
s
s
 (B) 
2
6 3
+
+
s
s
  
(C) 
1
2
+
+
s
s
 (D) 
2
1
+
+
s
s
 
 
Q.5 Assuming zero initial condition, the response ) (t y of the system given below to a unit step input  
) (t u is 
 
(A) ) (t u (B)  ) (t u t 
(C)  ) (
2
2
t u
t
 (D) ) (t u e
t - 
 
Q.6 
A polynomial 
4 3 2
4 3 2 1 0
( ) f x a x a x a x a x a = + + + - 
with all coefficients positive has  
(A) no real roots (B) no negative real root 
(C) odd number of real roots 
(D) at least one positive and one negative real root 
2013                                                                                                                             ELECTRONICS & COMMN. ENGG.  -  EC                                                                                                                       
 
EC-D 3/24
 
Q.7 The minimum eigenvalue of the following matrix is 
3 5 2
5 12 7
2 7 5
? ?
? ?
? ?
? ?
? ?
 
(A) 0 
(B) 1 (C) 2   (D) 3   
 
Q.8 Which one of the following statements is NOT TRUE for a continuous time causal and stable  
LTI system? 
(A) All the poles of the system must lie on the left side of the  j?
 
axis. 
(B) Zeros of the system can lie anywhere  in the  s-plane. 
(C) All the poles must lie within 1 s = . 
(D) All the roots of the characteristic equation must be located on the left side of the
 
j? axis. 
 
Q.9 In a MOSFET operating in the saturation region, the channel length modulation effect causes 
(A)   an increase in the gate-source capacitance 
(B)   a decrease in the transconductance 
(C)   a decrease in the unity-gain cutoff frequency   
(D)   a decrease in the output resistance 
 
Q.10 A band-limited signal with a maximum frequency of 5 kHz is to be sampled. According to the 
sampling theorem, the sampling frequency which is not valid is  
(A) 5 kHz (B) 12 kHz (C) 15 kHz  (D)  20 kHz 
 
Q.11 In a voltage-voltage feedback as shown below, which one of the following statements is TRUE if 
the gain k is increased? 
 
 
 
(A) The input impedance increases and output impedance decreases. 
(B) The input impedance increases and output impedance also increases. 
(C) The input impedance decreases and output impedance also decreases. 
(D) The input impedance decreases and output impedance increases. 
2013                                                                                                                             ELECTRONICS & COMMN. ENGG.  -  EC                                                                                                                       
 
EC-D 4/24
Q.12 For a periodic signal , ) 4 / 500 ( 6 300 10 100 30 ) ( p + + + = t sin t os c t sin t v the fundamental frequency in 
rad/s is  
(A) 100 (B) 300 (C) 500  (D) 1500  
 
Q.13 For 8085 microprocessor, the following program is executed. 
 
          MVI A, 05H; 
          MVI B, 05H; 
PTR: ADD B; 
          DCR B; 
          JNZ PTR; 
          ADI 03H; 
          HLT; 
 
At the end of program, accumulator contains 
(A) 17H (B) 20H (C) 23H  (D)  05H 
 
Q.14 The bit rate of a digital communication system is R kbits/s. The modulation used is 32-QAM. The 
minimum bandwidth required for ISI free transmission is  
(A) R/10 Hz (B) R/10 kHz (C)  R/5 Hz (D)  R/5 kHz 
 
Q.15 Consider a delta connection of resistors and its equivalent star connection as shown below. If all 
elements of the delta connection are scaled by a factor k, k> 0, the elements of the corresponding 
star equivalent will be scaled by a factor of 
R
B
R
C
R
b
R
a
R
c
R
A
 
(A) k
2
 (B) k (C)  1/k (D) k 
 
Q.16 In the circuit shown below what is the output voltage (V
out
) if a silicon transistor Q and an ideal  
op-amp are used? 
 
+15 V
– 15 V
5V
1 k? 
V
out
+
–
Q
 
 
(A) 15 V (B) 0.7 V   
(C)  0.7 V   (D)  15 V