S.MARIRAJAN T.V.SUDHIR

VALLIAMMAI ENGINEERING COLLEGE SRM NAGAR, KATTANKULATHUR 603 203

DEPARTMENT OF ELECTRONICS & COMMUNICATIONENGINEERING

Question Bank

2016 – 2017 Odd Semester

CS6304 – Analog and Digital Communication

Prepared by

Mr.S.Marirajan, A.P (Sr.G)

Mr.T.V.Sudhir, A.P (O.G)

S.MARIRAJAN T.V.SUDHIR

UNIT I – ANALOG COMMUNICATION

Noise: Source of Noise - External Noise- Internal Noise- Noise Calculation. Introduction to Communication Systems: Modulation – Types - Need for Modulation. Theory of Amplitude Modulation - Evolution and Description of SSB

Techniques - Theory of Frequency and Phase Modulation – Comparison of various Analog Communication System (AM

– FM – PM).

PART A

Q.No Questions BT

Level

Competence

1. Can you formulate Noise Figure and Signal to Noise ratio? BTL 6 Create

2. Draw the spectrum of AM signal and explain. BTL 1 Remember

3. Point out the applications of FM. BTL 4 Analyze

4. What is the need for modulation? BTL 1 Remember

5. Explain Noise and list the types of noise? BTL 2 Understand

6. Construct the spectrum of FM signal. BTL 5 Evaluate

7. Define angle modulation. BTL 1 Remember

8. What do you infer about frequency deviation? BTL 4 Analyze

9. How would you show the relationship between frequency and phase modulation? BTL 1 Remember

10. Summarize the advantages of SSBSC modulation. BTL6 Create

11. Distinguish between narrowband and wideband signal. BTL 2 Understand

12. Write about Carson’s rule. BTL 3 Apply

13. Tell modulation index and percent modulation. BTL 5 Evaluate

14. Outline the concept of Phase Modulation. BTL 4 Analyze

15. Compare AM with DSBSC & SSBSC. BTL 1 Remember

16. Show the advantages of SSB. BTL 3 Apply

17. Classify the types of modulation. BTL 2 Understand

18. List the major segments of electromagnetic spectrum and give their frequency

ranges.

BTL 1 Remember

19. Express Modulation & Demodulation. BTL 2 Understand

20. Illustrate amplitude modulation. BTL 3 Apply

S.MARIRAJAN T.V.SUDHIR

PART –B

1. Can you identify the principle of Angle Modulation. Derive phase deviation,

Modulation index, frequency deviation and percent modulation. (16)

BTL 4 Analyze

2. a. Can you recall the phasor diagram of wideband FM and explain about the

bandwidth of FM signal (8)

b. How would you show the difference between phase modulation and frequency

modulation. (8)

BTL 1 Remember

3. For an AM DSBFC wave with peak unmodulated carrier voltage Vc=10Vp, a load

resistance RL = 10 Ω and a modulation coefficient m = 1

a. Can you invent the Power of carrier, upper and lower side band and Total power

of modulate wave (8)

b. Can you invent the total sideband power and draw the power spectrum. (8)

BTL 6 Create

4. A modulating signal of 2 cos5000t is amplitude modulated over acarrier signal of

5cos20000t

a. What approach would you use to find the modulation index, LSB and VSB

frequencies (8)

b. How would you show your understanding of Bandwidth and the ratio of SideBand Power in the Total Power of AM wave. (8)

BTL 3 Apply

5. What is your opinion of the various analog communication systems. (16) BTL 5 Evaluate

6. a. What can you say about the percentage power saving when the carrier and one of

the sidebands are suppressed in an AM wave modulated to a depth of (1) 100 % (2)

50 % . (4)

b. How would you compare frequency modulation and phase modulation and their

inter relationship. (12)

BTL 2 Understand

7. a. What is the relationship between carrier and side band powers in an AM DSBFC

wave. (8)

b. What conclusions can you draw from the power distribution in AM DSB FC

system. (8)

BTL 4 Analyze

8. a. How would you show your understanding of the frequency analysis of Angle

modulated waves. (12)

b. you’ve learned Bandwidth requirements for the above. (4)

BTL 3 Apply

9. A. The first stage of a two stage amplifier has a voltage gain of 10, a 600 Ω input

resistor , a 1600 Ω equivalent noise resistance and a 27 kΩ output resistor . For the

second stage these values are 25, 81kΩ , 10kΩ and 1 MΩ respectively. What is the

equivalent input noise resistance of this two stage amplifier and also what is the

noise figure of the amplifier if it is driven by a generator whose output impedance

is 50 Ω. (8)

BTL 1 Remember

S.MARIRAJAN T.V.SUDHIR

b. How would you show the expression for instantaneous voltage of AM wave? (8)

10. a. State in your own words about internal noise (8)

b. In modulation by several sine waves simultaneously, in AM, the bandwidth

required is twice the highest modulating frequency. How would you summarize

using appropriate expressions to prove this concept (8)

BTL 2 Understand

11. a. How would you explain the nature of SSB spectrum if the modulating signal is

m(t)= cos2𝜋.100t + cos2π.2000t and carrier is given by c(t) = cos2π.10000t. (8)

b. Can you recall the relationship between the instantaneous carrier frequency and

modulating signal for FM. (8)

BTL 1 Remember

12. State in your own words about the noise with suitable examples. (16) BTL 2 Understand

13. a. Can you distinguish between modulation index for FM and PM. (4)

b. What is the relationship between modulation index and modulating signal for

FM and PM. (12)

BTL 4 Analyze

14. How would you explain Amplitude modulation, its generation and detection with the

help of mathematical expressions. (16)

BTL 1 Remember

UNIT II - DIGITAL COMMUNICATION

Amplitude Shift Keying (ASK) – Frequency Shift Keying (FSK) Minimum Shift Keying (MSK) –Phase Shift Keying

(PSK) – BPSK – QPSK – 8 PSK – 16 PSK - Quadrature Amplitude Modulation (QAM) – 8 QAM – 16 QAM – Bandwidth Efficiency– Comparison of various Digital Communication System (ASK – FSK – PSK – QAM).

PART A

Q.No Questions BT

Level

Competence

1. Analyze the relationship between bit rate and baud for a FSK system? BTL 4 Analyze

2. Draw the ASK signal for the given message signal 101101.

BTL 1 Remember

3. Show the difference between QPSK and BPSK. BTL 3 Apply

4. Can you formulate the advantages of BPSK BTL 6 Create

5. Tell the advantage of QPSK? BTL 5 Evaluate

6. Summarize the advantages of digital communication. BTL 2 Understand

7. Outline the constellation diagram of QPSK signal. BTL 1 Remember

8. Devise the concept of MSK. BTL 6 Create

S.MARIRAJAN T.V.SUDHIR

9. Illustrate your understanding of Nyquist sampling theorem.

BTL 3 Apply

10. Give the main idea of ASK. BTL 2 Understand

11. List the function of FSK? BTL 4 Analyze

12. State bandwidth efficiency.

BTL 1 Remember

13. Compare ASK and FSK. BTL 5 Evaluate

14. How would you show the QPSK signal for the binary sequence 11001100?

BTL 1 Remember

15. What facts would you select to show ASK as ON-OFF keying? BTL 3 Apply

16. State in your own words about information capacity and bit rate. BTL 2 Understand

17. Identify how QPSK is different from 16 PSK signal in terms of bandwidth?

BTL 1 Remember

18. Point out the concept of Aliasing. BTL 4 Analyze

19. What is meant by PSK and draw its waveform for the data 10110.

BTL 2 Understand

20. Cite the difference between standard FSK and MSK ? Also write the advantage of

MSK ?

BTL 1 Remember

PART –B

1. Can you formulate a theory for amplitude shift keying systems with neat diagram.

(16)

BTL 6 Create

2. How would you explain the constellation diagram of QPSK modulation and it’s

modulator and demodulator. (16)

BTL 1 Remember

3. How would you show your understanding of the operations of Non-coherent and

coherent ASK modulators. (16)

BTL 3 Apply

4. What is your opinion of minimum shift keying with suitable diagrams (16) BTL 5 Evaluate

5. For a BPSK modulator with a Carrier frequency of 70 MHz and an input bit rate of

10 Mbps,

a.What can you say about the maximum and minimum upper and lower side

frequencies, draw the output spectrum, (8)

b. How would you summarize the minimum Nyquist bandwidth, and calculate the

baud rate (Assume f= 5MHz) (8)

BTL 2 Understand

6. a. Can you identify the principle of Binary phase shift keying? also obtain the

minimum double sided Nyquist bandwidth. (8)

b. Discuss in detail the BPSK transmitter and Receiver (8)

BTL 4 Analyze

S.MARIRAJAN T.V.SUDHIR

7. a. How would you show the working of BFSK transmitter and receiver with

necessary equations and block diagram. (8)

b. How would you describe coherent and non coherent detection and compare the

various digital communication systems. (8)

BTL 1 Remember

8. Can you identify the bandwidth considerations of 8-PSK system. (16) BTL 4 Analyze

9. State in your own words

a. QPSK transmitter with relevant expressions and figures (8)

b. Receiver and bandwidth considerations of QPSK with relevant expressions and

figures (8)

BTL 2 Understand

10. What approach would you use to explain the principle of

a. FSK transmitter (8)

b. FSK receiver. (8)

BTL 3 Apply

11. What is the significance of QAM? Can you recall the operation of 8 QAM

transmitter and receiver using block diagram and truth table. (16)

BTL 1 Remember

12. What inference can you make on carrier recovery? Discuss how carrier recovery is

achieved by the squaring loop and Costas loop circuits. (16)

BTL 4 Analyze

13. How would you compare the various digital communication systems. (16) BTL 2 Understand

14. How would you explain the method of generation of QAM and demodulation of

the same. (16)

BTL 1 Remember

UNIT III - DATA AND PULSE COMMUNICATION

Data Communication: History of Data Communication - Standards Organizations for Data Communication- Data

Communication Circuits - Data Communication Codes - Error Detection and Correction Techniques - Data communication

Hardware - serial and parallel interfaces. Pulse Communication: Pulse Amplitude Modulation (PAM) – Pulse Time Modulation (PTM) – Pulse code Modulation (PCM) - Comparison of various Pulse Communication System (PAM – PTM

– PCM).

PART A

Q.No Questions BT

Level

Competence

1. Outline the function of ASCII code.

BTL 4 Analyze

2. What is the need for companding in a PCM system? BTL 1 Remember

S.MARIRAJAN T.V.SUDHIR

3. Justify why the quantization noise cannot be removed completely in PCM. How

do you reduce this noise?

BTL 6 Create

4. Classify the two primary methods used for error correction. BTL 2 Understand

5. What facts would you select to show the types of Data Transmission? BTL 3 Apply

6. How would you prove which error detection is simple and which one is more

reliable?

BTL 5 Evaluate

7. How would you show PPM is derived from PWM? BTL 1 Remember

8. What is your opinion of Data Terminal Equipment? Give examples. BTL 5 Evaluate

9. Distinguish the advantages and disadvantages of error detection? BTL 2 Understand

10. Can you list out the common features provided by data communication

MODEMS.

BTL 4 Analyze

11. State sampling rate. BTL 1 Remember

12. Compile a theory for forward error correction. BTL 6 Create

13. Identify why we encounter aperture effect in PAM? How will you rectify it? BTL 1 Remember

14. Compare error detection & error correction. BTL 4 Analyze

15. What can you say about the ODD and EVEN parity bits for the ASCII character R

whose hex code is 52?

BTL 2 Understand

16. Illustrate non-linear encoding in PCM system. BTL 3 Apply

17. Can you recall sampling theorem for band limited signal of finite energy? BTL 1 Remember

18. State in your own words about the types of pulse modulation systems? BTL 2 Understand

19. Interpret the concept of CRC? BTL 3 Apply

20. Write about slope overload error. BTL 1 Remember

PART –B

1. Recall the differentiate between serial and parallel interfaces. (16) BTL 1 Remember

2. Estimate the VRC and LRC for the following ASCII encoded message

“THE CAT”. Use odd parity for VRC and even parity for LRC. (16)

BTL 2 Understand

3. Analyze the Longitudinal redundancy checking and Checksum with example. (16) BTL 4 Analyze

4. a. Interpret the History of Data Communication. (8)

b.Illustrate the Data Communication codes. (8)

BTL 3 Apply

5. Summarize about parallel interface with its features. (16) BTL 5 Evaluate

S.MARIRAJAN T.V.SUDHIR

6. a.Describe in detail about the Standards Organizations for data communication.

(8)

b. State the concept of Data Communication circuits using a basic block diagram.

(8)

BTL 1 Remember

7. Predict the BCS for the following data and CRC generating polynomial. Data

G(x) = x10

+ x9

+ x7+ x

5 + x

3+ x

2 +x

1 + x

0 CRC 16 polynomial, G(x) = x

16 +

x15

+ x2

+ x0 (16)

BTL 2 Understand

8. Write about the generation of PAM and it’s demodulation. (16) BTL 1 Remember

9. Identify the features and purposes of serial interfaces. Describe t h e mechanical,

electrical and functional characteristics of RS 232 interface. (16)

BTL 4 Analyze

10. a.Compare the various Pulse Communication Systems with waveforms. (16) BTL 6 Create

11. Show Vertical redundancy checking and Cyclic redundancy checking under Error

detection with example. (16)

BTL 3 Apply

12.

a.Draw the block diagram of PCM transmitter and receiver and explain. (12)

b.What is ISI? How can it be reduced? (4)

BTL 1 Remember

13.

Point out Error correction schemes. (16) BTL 4 Analyze

14. For a 12bit data string of 101100010010. Determine the number of Hamming bits

required, arbitrarily place the Hamming bits into the data stream, Identify the logic

condition of each Hamming bit. Assume an arbitrary single bit transmission error

and prove that the Hamming code will successfully detect the error. (16)

BTL 2 Understand

UNIT IV - SOURCE AND ERROR CONTROL CODING

Entropy, Source encoding theorem, Shannon fano coding, Huffman coding, mutual information, channel capacity,

channel coding theorem, Error Control Coding, linear block codes, cyclic codes, convolution codes, viterbi decoding algorithm.

PART A

Q.No Questions BT

Level

Competence

1. Identify the entropy of the system for an event that has six possible outcomes with

probabilities 1/2,1/4,1/8,1/16,1/32?

BTL 1 Remember

2. Express prefix coding. BTL 2 Understand

S.MARIRAJAN T.V.SUDHIR

3. Can you identify the hamming distance between the following code words C1=

1000111 and C2 = 0001011.

BTL 4 Analyze

4. How would you organize the formula to show mutual information? BTL 3 Apply

5. What is mutual information and state its properties? BTL 1 Remember

6. State in your own words about the Shannon’s theorem on information capacity of a

channel.

BTL 2 Understand

7. What approach would you use to differentiate lossy source coding from lossless

source coding?

BTL 3 Apply

8. Can you formulate a theory for source coding theorem? BTL 6 Create

9. What is the theme of source coding theorem? BTL 4 Analyze

10. How would you describe the channel capacity of a discrete memory less channel? BTL 1 Remember

11. Illustrate Bandwidth efficiency. BTL 2 Understand

12. Show that if Ci and Cj are two code vectors in the (n,k) linear block code , then their

sum is also a code vector with an example?

BTL 1 Remember

13. Demonstrate the difference between Shannon fano coding from lossy source

coding.

BTL 3 Apply

14. State entropy. BTL 1 Remember

15. What is the main idea of Information rate? BTL 2 Understand

16. Can you explain about the linear block codes? BTL 1 Remember

17. Compile the difference between cyclic codes and convolution codes. BTL 6 Create

18. Evaluate cyclic codes and convolution codes. BTL 5 Evaluate

19. Analyze the function of vertical redundancy checking. BTL 4 Analyze

20. What is your opinion of vertical redundancy checking? BTL 5 Evaluate

PART –B

1. Describe how Viterbi procedure is used for decoding convolution codes. (16) BTL 1 Remember

2. a.Interpret Mutual information and its properties in detail. (8)

b. Show the difference between Source coding theorem and Channel coding theorem

with equations. (8)

BTL 3 Apply

3. Consider a discrete memoryless source with source alphabets S = S0, S1, S2 and

their probabilities P0 = ¼, P1 = ¼ , P2 = ¼ . Generate the entropy of the source H(X)

& H(X2). Also prove that the entropy of the extended source is equal to n times H(X)

i.e., H(X2) = 2*H(X). (16)

BTL 5 Evaluate

S.MARIRAJAN T.V.SUDHIR

4. Show the expression for channel capacity of a continuous channel. Comment on the

trade off between SNR and capacity. (16)

BTL 1 Remember

5. a.Estimate a syndrome calculator for a 7,4 cyclic code generated by the polynomial

G(x) = X3 + X + 1. Identify the syndrome for the received vector 1001101. (8)

b.Predict a cyclic encoder for the same 7,4 cyclic code and obtain the code vector

for the message vector 1100. (8)

BTL 2 Understand

6. Compare the Linear Block Codes and Binary Cyclic Codes in detail. (16) BTL 4 Analyze

7. A source generates five messages m0,m1,m2,m3 and m4 with probabilities

0.55,0.15,0.15,0.10 and 0.05 respectively. The successive messages emitted by the

source are statistically independent. Identify the code words for the messages and

efficiency using Shannon Fano Algorithm. (16)

BTL 1 Remember

8. a.Estimate the capacity of a standard 4kHz telephone channel with a 32 dB signal to

noise ratio. (8)

b.A System has a bandwidth of 4kHz and the signal to noise ratio 28 dB at the input

to the receiver. Evaluate information carrying capacity, capacity of the channel if its

bandwidth is doubled, while the transmitted signal power remains constant. (8)

BTL 6 Create

9. a.Write the Huffman code for a discrete memoryless source with probability

statistics 0.1,0.1,0.2,0.2,0.4. (8)

b.Describe the concept of Channel coding theorem. (8)

BTL 1 Remember

10. The parity check matrix of a particular (7,4) linear block code is given by

[𝐻] = [1 1 1 0 1 0 01 1 0 1 0 1 01 0 1 1 0 0 1

]

(i)Point out Generator matrix and List of all the code vectors (8)

(ii)Identify the minimum distance between code and vector? (8)

BTL 4

Analyze

11. Report Error Control Codes and its applications in detail. (16) BTL 3 Apply

12. Give main idea of Source Coding Theorem? Explain it with suitable examples. (16) BTL 2 Understand

13. Analyze the functioning of convolution codes with example. (16) BTL 4 Analyze

14. Illustrate Entropy Techniques and its properties in detail. (16) BTL 2 Understand

UNIT V - MULTI-USER RADIO COMMUNICATION

Advanced Mobile Phone System (AMPS) - Global System for Mobile Communications (GSM) - Code division

multiple access (CDMA) – Cellular Concept and Frequency Reuse - Channel Assignment and Hand - Overview of Multiple Access Schemes - Satellite Communication - Bluetooth.

PART A

S.MARIRAJAN T.V.SUDHIR

Q.No

Questions

BT

Level

Competence

1. What is near far effect in a CDMA system? BTL 1 Remember

2. What is your opinion of look angles of a satellite? BTL 5 Evaluate

3. State in your own words about TDMA & CDMA. BTL 2 Understand

4. Identify the various handovers carried out in GSM. BTL 1 Remember

5. Classify multiplexing and multiple access. BTL 3 Apply

6. Write about the Bluetooth technology. BTL 1 Remember

7. What conclusions can you give by footprint? BTL 4 Analyze

8. Explain chip code in CDMA system? BTL 2 Understand

9. List the functions of a MODEM. BTL 1 Remember

10. Infer the meaning GSM. BTL 4 Analyze

11. State the term frequency reuse factor in a cellular communication system. BTL 1 Remember

12. Can you predict the applications of satellite communication? BTL 6 Create

13. Give main idea of handoff. BTL 2 Understand

14. Why did hexagons employed to model coverage areas of mobile communication? BTL 1 Remember

15. Illustrate about orthogonal code. BTL 3 Apply

16. How would you compare FDMA & TDMA? BTL 2 Understand

17. Tell the basic components of a satellite earth station subsystem. BTL 5 Evaluate

18. Interpret the frequency hopping. BTL 3 Apply

19. Summarize the function of a transponder. BTL 6 Create

20. Point out Kepler’s three laws of planetary motions. BTL 4 Analyze

PART-B

1. Draw the architecture of GSM system and explain the function of each block. (16) BTL 1 Remember

2. a.Point out Direct Broadcast Satellite. (8) BTL 4 Analyze

S.MARIRAJAN T.V.SUDHIR

b.List the functionality of Bluetooth. (8)

3. Illustrate TDMA in wireless communication systems and it’s uses. (16) BTL 2 Understand

4. Describe the concept of cellular topology and cell fundamentals with examples. (16) BTL 1 Remember

5. Elaborate on the difference betweens GSM & CDMA. (16) BTL 6 Create

6. Write notes on multiple access techniques and it’s types. (16) BTL 1 Remember

7. Interpret the need for multiple access techniques. Draw the block diagram of a

TDMA system and explain. Produce its advantages and disadvantages over FDMA

technique. (16)

BTL 3 Apply

8. Outline the operation of a satellite communication system with a block diagram. (16) BTL 1 Remember

9. Analyze the Satellite frequency plans and frequency allocations in detail. (16) BTL 4 Analyze

10. a. Report the channel assignment strategies. (8)

b. Show the concept of Handoff in cellular communication. (8)

BTL 3 Apply

11. Discuss in detail about Cellular concept and Frequency reuse. (16) BTL 2 Understand

12. Examine the Satellite Access and Satellite Earth Station in detail. (16) BTL 4 Analyze

13. a . Explain the operation of CDMA multiplexing system. (10)

b. Identify the advantages of CDMA over TDMA multiple access schemes. (6)

BTL 2 Understand

14. Summarize in detail Advanced Mobile Phone Systems (AMPS). (16) BTL 5 Evaluate