Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Attempt any seven of the following:
Define Apogee and Perigee.
What is the difference between LEO and GEO satellites?
What is intermodal dispersion?
What is acceptance angle? Discuss its importance.
Compare the probability of error for ASK and BPSK modulation technique.
State the sampling theorem.
What is aliasing effect? How can it be reduced?
Mention the uses of a limiter and discriminator in FM demodulation.
Draw the block diagram of narrow band FM generation system.
Draw the block diagram of SSB synchronous demodulation system.
Q.2 Solve both questions :
Explain the concept of AM SSB modulation and demodulation with block diagram and also derive mathematical expression for coherent detection.
What are pre-emphasis and de-emphasis and how is SNR improved by using pre-emphasis and de-emphasis?
Q.3 Solve both questions :
Prove that bandwidth of an FM wave is infinity. Also represent the single tone FM wave as function of Bessel's function.
Derive the expression for the probability of error of the binary phase shift keying (BPSK) signal.
Q.4 Solve both questions :
Draw and explain the block diagram of phase shift method for generating the SSB signal.
Explain the block diagram of super-heterodyne receiver. Determine the image frequency for standard broadcast AM receiver using 455 kHz IF and tuned to a station at 640 kHz.
Q.5 Solve both questions :
Explain flat top sampling in detail.
Explain the sampling process of a signal mathematically. How to generate PPM from PWM signal?
Q.6 Solve both questions :
PCM system uses a uniform quantizer followed by a 7-bit binary encoder. The bit rate of the system is equal to $ 50 \times 10^6 \text{ bits/sec} $. (i) What is the maximum message signal bandwidth for which the system operates satisfactory? (ii) Calculate the output signal-to-noise ratio when full load sinusoidal modulating wave of frequency 1 MHz is applied to the input.
Describe the operation of phase discriminator based FM demodulator.
Q.7 Solve both questions :
What is Differential Pulse Code Modulation? Explain the working of DPCM with a proper block diagram.
(i) A radio transmitter radiates 10 kW and carrier power is 8.5 kW. Calculate the modulation index. (ii) A broadcast radio transmitter radiates 10 kW, when modulation percentage is 60. Calculate the carrier power.
Q.8 Solve both questions :
Draw and explain the operation of optical receiver.
Derive the expression of acceptance angle for skew rays. An optical fiber has numerical aperture of 0.344. What is the acceptance angle for meridional rays? Calculate the acceptance angle for skew rays which change direction by 100° at each reflection.
Q.9 Solve this question :
State the Kepler's law of planetary motion. Explain the ascending and descending nodes of a satellite.
What is look angle? How does it calculate with shifting of satellite with respect to earth station?
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Attempt any seven of the following:
Define Apogee and Perigee.
What is the difference between LEO and GEO satellites?
What is intermodal dispersion?
What is acceptance angle? Discuss its importance.
Compare the probability of error for ASK and BPSK modulation technique.
State the sampling theorem.
What is aliasing effect? How can it be reduced?
Mention the uses of a limiter and discriminator in FM demodulation.
Draw the block diagram of narrow band FM generation system.
Draw the block diagram of SSB synchronous demodulation system.
Q.2 Solve both questions :
Explain the concept of AM SSB modulation and demodulation with block diagram and also derive mathematical expression for coherent detection.
What are pre-emphasis and de-emphasis and how is SNR improved by using pre-emphasis and de-emphasis?
Q.3 Solve both questions :
Prove that bandwidth of an FM wave is infinity. Also represent the single tone FM wave as function of Bessel's function.
Derive the expression for the probability of error of the binary phase shift keying (BPSK) signal.
Q.4 Solve both questions :
Draw and explain the block diagram of phase shift method for generating the SSB signal.
Explain the block diagram of super-heterodyne receiver. Determine the image frequency for standard broadcast AM receiver using 455 kHz IF and tuned to a station at 640 kHz.
Q.5 Solve both questions :
Explain flat top sampling in detail.
Explain the sampling process of a signal mathematically. How to generate PPM from PWM signal?
Q.6 Solve both questions :
PCM system uses a uniform quantizer followed by a 7-bit binary encoder. The bit rate of the system is equal to $ 50 \times 10^6 \text{ bits/sec} $. (i) What is the maximum message signal bandwidth for which the system operates satisfactory? (ii) Calculate the output signal-to-noise ratio when full load sinusoidal modulating wave of frequency 1 MHz is applied to the input.
Describe the operation of phase discriminator based FM demodulator.
Q.7 Solve both questions :
What is Differential Pulse Code Modulation? Explain the working of DPCM with a proper block diagram.
(i) A radio transmitter radiates 10 kW and carrier power is 8.5 kW. Calculate the modulation index. (ii) A broadcast radio transmitter radiates 10 kW, when modulation percentage is 60. Calculate the carrier power.
Q.8 Solve both questions :
Draw and explain the operation of optical receiver.
Derive the expression of acceptance angle for skew rays. An optical fiber has numerical aperture of 0.344. What is the acceptance angle for meridional rays? Calculate the acceptance angle for skew rays which change direction by 100° at each reflection.
Q.9 Solve this question :
State the Kepler's law of planetary motion. Explain the ascending and descending nodes of a satellite.
What is look angle? How does it calculate with shifting of satellite with respect to earth station?
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer any seven of the following questions:
What is the criterion for Carson's bandwidth calculation?
List the advantages of DSB-FC modulation scheme.
A signal has frequency component from 300 Hz to 1.8 kHz. What is the minimum possible rate at which the signal has to be sampled?
Define the numerical aperture of step index fiber.
What is the need of cladding?
What are the advantages of geostationary satellite?
Mention the uses of frequency discriminator in FM demodulation.
Write the advantages of hand-off process.
What do you mean by baseband signal?
Compare the spectrum occupancy of PSK and FSK schemes.
Q.2 Solve both questions :
What is the basic limitation of SSB modulation scheme? How is it eliminated by VSB modulation?
Draw the block diagram of super heterodyne AM receiver and explain the function of IF amplifier.
Q.3 Solve both questions :
80 micrometer core diameter single-mode fiber has a core refractive index of 2, relative refractive index difference of 0.3% and operating wavelength of 1.55 micrometer. Determine critical radius of curvature. Explain bending losses.
Discuss the Armstrong's method of indirect FM generation in detail.
Q.4 Solve both questions :
What is ISI? Explain how ISI can be removed by employing a raised cosine filter.
Derive the output SNR of AM envelop detector. Also calculate its figure of merit.
Q.5 Solve both questions :
Explain the convolution codes, their advantages and disadvantages.
A sinusoidal message signal of peak voltage 20 V and peak frequency of 5 kHz is transmitted through 256 levels PCM system. The sampling rate is 25% higher than Nyquist rate Calculate the sampling frequency, bit rate, bandwidth, step size, maximum quantization error and SNR in dB.
Q.6 Solve both questions :
Explain the sampling process of a signal mathematically. Write how to generate PPM from PWM signal?
Derive the power calculation of AM signal.
Q.7 Solve both questions :
What is the probability of error in presence of white noise for BPSK system? We are required to transmit $ 2.08 \times 10^6 $ binary digits per second with $ P_b \le 10^{-7} $. The channel noise PSD is $ Sn(f)=10^{-8} $. Determine the transmission bandwidth and signal power required in binary.
What are the noise considerations in PCM? Explain the TDM-PAM concept.
Q.8 Solve both questions :
An angle modulated signal with carrier frequency $ \omega_c = 2\pi \times 10^5 \text{ rad/sec} $ is given as follow: $ \phi_{FM}(t) = 10 \cos(\omega_c t + 5 \sin(3000t) + 10 \sin(2000t)) $. (i) Find power of modulated signal. (ii) Find the maximum frequency deviation. (iii) Find the maximum phase deviation. (iv) Estimate the bandwidth of FM signal.
Explain the different types of diversity technique used in wireless communication system.
Q.9 Solve both questions :
Explain telemetry, tracking and command control system in detail.
Explain Snell's law. What is total internal reflection? Explain with suitable diagram.
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer any seven of the following questions:
What is the criterion for Carson's bandwidth calculation?
List the advantages of DSB-FC modulation scheme.
A signal has frequency component from 300 Hz to 1.8 kHz. What is the minimum possible rate at which the signal has to be sampled?
Define the numerical aperture of step index fiber.
What is the need of cladding?
What are the advantages of geostationary satellite?
Mention the uses of frequency discriminator in FM demodulation.
Write the advantages of hand-off process.
What do you mean by baseband signal?
Compare the spectrum occupancy of PSK and FSK schemes.
Q.2 Solve both questions :
What is the basic limitation of SSB modulation scheme? How is it eliminated by VSB modulation?
Draw the block diagram of super heterodyne AM receiver and explain the function of IF amplifier.
Q.3 Solve both questions :
80 micrometer core diameter single-mode fiber has a core refractive index of 2, relative refractive index difference of 0.3% and operating wavelength of 1.55 micrometer. Determine critical radius of curvature. Explain bending losses.
Discuss the Armstrong's method of indirect FM generation in detail.
Q.4 Solve both questions :
What is ISI? Explain how ISI can be removed by employing a raised cosine filter.
Derive the output SNR of AM envelop detector. Also calculate its figure of merit.
Q.5 Solve both questions :
Explain the convolution codes, their advantages and disadvantages.
A sinusoidal message signal of peak voltage 20 V and peak frequency of 5 kHz is transmitted through 256 levels PCM system. The sampling rate is 25% higher than Nyquist rate Calculate the sampling frequency, bit rate, bandwidth, step size, maximum quantization error and SNR in dB.
Q.6 Solve both questions :
Explain the sampling process of a signal mathematically. Write how to generate PPM from PWM signal?
Derive the power calculation of AM signal.
Q.7 Solve both questions :
What is the probability of error in presence of white noise for BPSK system? We are required to transmit $ 2.08 \times 10^6 $ binary digits per second with $ P_b \le 10^{-7} $. The channel noise PSD is $ Sn(f)=10^{-8} $. Determine the transmission bandwidth and signal power required in binary.
What are the noise considerations in PCM? Explain the TDM-PAM concept.
Q.8 Solve both questions :
An angle modulated signal with carrier frequency $ \omega_c = 2\pi \times 10^5 \text{ rad/sec} $ is given as follow: $ \phi_{FM}(t) = 10 \cos(\omega_c t + 5 \sin(3000t) + 10 \sin(2000t)) $. (i) Find power of modulated signal. (ii) Find the maximum frequency deviation. (iii) Find the maximum phase deviation. (iv) Estimate the bandwidth of FM signal.
Explain the different types of diversity technique used in wireless communication system.
Q.9 Solve both questions :
Explain telemetry, tracking and command control system in detail.
Explain Snell's law. What is total internal reflection? Explain with suitable diagram.