EC-403 RGPV B.Tech
Analog Communication (AC)
Previous year papers and the official syllabus are free to read, no account needed.
Previous Year Papers
6 papers, latest Jun 2025
- EC-403 paper, Jun 2025
- EC-403 paper, Dec 2024
- EC-403 paper, Jun 2024
- EC-403 paper, Nov 2023
- EC-403 paper, Jun 2023
- EC-403 paper, Jun 2022
Syllabus, notes and important questions for EC-403
Syllabus units
Topics as the official RGPV syllabus lists them.
Unit 1 Frequency domain representation of signal 14 topics
- Fourier transform and its properties
- Condition of existence of Fourier transform
- Fourier transform of impulse
- Fourier transform of step
- Fourier transform of signum
- Fourier transform of cosine
- Fourier transform of sine
- Fourier transform of gate pulse
- Fourier transform of constant
- Properties of impulse function
- Convolution theorem (time & frequency)
- Correlation (auto & cross)
- Energy spectral density
- Power spectral density
Unit 2 Overview of communication system and amplitude modulation 12 topics
- Overview of communication system
- Communication channels
- Need for modulation
- Baseband signals
- Pass‑band signals
- Amplitude Modulation (AM)
- Double side band with carrier (DSB‑C)
- Double side band without carrier (DSB‑SC)
- Single side band modulation (SSB)
- Generation of AM
- Vestigial side band (VSB)
- Detection of VSB
Unit 3 Angle modulation and FM communication 17 topics
- Angle modulation
- Narrowband FM
- Wideband FM
- FM frequency spectrum
- Transmission bandwidth of FM
- FM generation methods – direct
- FM generation methods – indirect
- FM detection – balanced discriminator
- FM detection – phase‑shift discriminator
- FM detection – PLL detector
- Pre‑emphasis
- De‑emphasis
- FM transmitter block diagram
- FM receiver block diagram
- Automatic Gain Control (AGC)
- Automatic Volume Control (AVC)
- Automatic Frequency Control (AFC)
Unit 4 AM transmitter and receiver characteristics 12 topics
- AM transmitter
- AM receiver
- Tuned radio receiver
- Super‑heterodyne receiver
- Limitations of TRF receivers
- Intermediate frequency (IF)
- Image signal rejection
- Selectivity
- Sensitivity
- Fidelity
- Noise in AM
- Noise in FM
Unit 5 Noise in analog communication 11 topics
- Classification of noise
- Sources of noise
- Noise figure
- Noise temperature
- Noise bandwidth
- Noise figure measurement
- Noise in analog modulation
- Figure of merit for AM
- Figure of merit for FM
- Effect of noise on AM receivers
- Effect of noise on FM receivers
Exam insights
Counted from 6 past EC-403 papers.
Marks asked per paper, by unit
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Unit 1 Frequency domain representation of signal 19 marks
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Unit 2 Introduction 33 marks
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Unit 3 Types of angle modulation 29 marks
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Unit 4 AM transmitter& receiver 18 marks
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Unit 5 Noise 12 marks
Average marks of the questions from each unit in one paper. You answer only some of them, so the total is more than the paper’s maximum.
Asked again and again
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Draw the block diagram of a superheterodyne receiver and explain its operation / function of each block.
Asked 5 times: 2024, 2023, 2020, 2019
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Explain what modulation is and why it is needed, including its main advantages, with a block diagram of a communication system.
Asked 4 times: 2025, 2024, 2023, 2019
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Determine the Fourier transform of standard signals: unit impulse, unit step, signum, sine and cosine functions.
Asked 3 times: 2024, 2023, 2020