IT-404 RGPV B.Tech

Analog & Digital Communication (ADC)

Previous year papers and the official syllabus are free to read, no account needed.

Previous Year Papers

6 papers, latest Jun 2026

Free

Topics as the official RGPV syllabus lists them.

Unit 1 Signals and Systems 10

Block diagram of a communication system
Signal definition and classification (continuous, discrete, deterministic, non‑deterministic, periodic, non‑periodic, energy, power, analog, digital)
Electromagnetic spectra
Standard signals: DC, sinusoidal, unit‑step, ramp, signum, rectangular pulse, impulse ($\delta$) signal
System definition and classification (linear, non‑linear, time‑variant, time‑invariant, causal, non‑causal, stable, unstable)
Fourier Transform: time‑domain and frequency‑domain representation of signals
Fourier Transform properties and existence conditions
Transforms of gate, unit‑step, constant, impulse, sine and cosine waves
Shifting property of the delta function
Convolution and the time‑ and frequency‑domain convolution theorems

Unit 1 notes

Unit 2 Amplitude Modulation 11

Purpose of modulation and classification of amplitude modulation techniques
Double‑sideband full‑carrier (DSB‑FC) modulation and modulation index
Frequency spectrum of AM wave, linear versus over‑modulation
Power relations and transmission efficiency in AM
Modulation by a complex signal and bandwidth of AM
AM modulators: square‑law and switching modulators, advantages/disadvantages
Suppressed‑carrier AM systems (DSB‑SC, SSB‑SC, VSB‑SC) and comparative analysis
Demodulation techniques: square‑law detector, envelope detector, synchronous detection
Low‑power and high‑power AM transmitters
AM receivers: TRF and super‑heterodyne architectures
Receiver performance parameters: sensitivity, selectivity, fidelity

Unit 2 notes

Unit 3 Angle Modulation 7

Introduction to angle modulation and its categories
Frequency modulation (FM): frequency deviation, modulation index, deviation ratio, bandwidth requirement of FM wave
Types of FM
Phase modulation (PM) and differences between FM and PM
Direct and indirect methods of FM generation
FM demodulators: slope detector, Foster‑Seeley discriminator, ratio detector
Overview of pulse modulation systems

Unit 3 notes

Unit 4 Sampling and Pulse Modulation 12

Sampling of signals and sampling theorem for low‑pass and band‑pass signals
Pulse amplitude modulation (PAM) and time‑division multiplexing (TDM)
Channel bandwidth considerations for PAM‑TDM signals
Types of sampling: instantaneous, natural, flat‑top, aperture effect
Pulse‑position modulation and pulse‑duration modulation
Digital signal concepts: quantization, quantization error
Pulse code modulation (PCM) and signal‑to‑noise ratio
Companding techniques
Data rate, baud rate, and bit rate calculations
Multiplexed PCM signals
Differential PCM (DPCM), delta modulation (DM) and adaptive delta modulation (ADM)
Comparative analysis of various pulse‑code systems

Unit 4 notes

Unit 5 Digital Modulation Techniques 8

Unit 5 notes

Counted from 6 past IT-404 papers.

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.

Explain the generation/transmitter and demodulation/detection/receiver of QAM with block diagrams, including 8-QAM operation, constellation and comparison aspects.

Asked 6 times: 2025, 2023, 2020
Draw the block diagram of a basic communication system and explain the function of each block.

Asked 3 times: 2026, 2024, 2019
Find the Fourier Transform of the gate function, unit step function and delta function.

Asked 3 times: 2025, 2024, 2019