RTU Kota BTech 3rd Semester Signals and Systems Question Paper 2025 (ECE and BI)

RTU Signals and Systems 2025 Paper Review

Preparing for the Rajasthan Technical University BTech Signals and Systems exam requires a firm grasp of mathematical transformations, system linearity, and frequency-domain analysis. For Electronics and Communication or Biomedical Engineering students designing filters, processing bio-electric signals, or analyzing communication channels, mastering mathematical modeling is foundational. You cannot design reliable communication networks or medical imaging systems without understanding impulse response, convolution, and frequency responses.

The 2025 paper tests your capability to evaluate system properties, compute convolution integrals, determine Fourier coefficients, and analyze system stability using mathematical transforms. Publishing this specific 3rd-semester paper review directly to your exam support website provides your users exactly what they need to understand how examiners construct mathematical problems and distribute marks across transformation modules. This targeted preparation strategy helps approach the exam confidently, Aryan.

Understanding the Exam Pattern

The RTU theory examination is a three-hour paper worth 70 marks. The paper features three distinct sections designed to evaluate both theoretical classification definitions and complex mathematical derivations.

Part A: This section contains ten compulsory questions worth two marks each. You must define terms like causal system, state the condition for system stability, define the Dirichlet conditions, or explain the property of time-invariance under 30 words.

Part B: You will find seven questions here. You must answer five of them. Each question is worth four marks. Your answers require explaining the properties of the ROC in Laplace transforms, checking the linearity of a specific differential equation, or finding the discrete-time Fourier transform of a basic sequence.

Part C: This section offers five major questions. You need to answer three. Each question carries ten marks. These require you to calculate the convolution integral of two continuous-time signals, find the trigonometric Fourier series of a periodic square wave, or determine the inverse Z-transform of a rational transfer function.

Core Topics Evaluated in the Paper

The 2025 question paper covers several critical modules that establish the mathematical rules for signal analysis. Focus your study time on these specific areas to maximize your score.

Classification of Signals and Systems

This module evaluates your ability to categorize signals and test system properties. Practice determining whether a given signal is an energy or power signal by calculating its total energy or average power. You must master testing systems for linearity, time-invariance, causality, and bounded-input bounded-output (BIBO) stability.

Linear Time-Invariant Systems and Convolution

LTI systems are completely characterized by their impulse response. You must master the execution of both the convolution integral for continuous-time systems and the convolution sum for discrete-time systems. Practice graphical convolution methods step by step, showing the folding, shifting, multiplication, and integration phases clearly.

$$y(t) = \int_{-\infty}^{\infty} x(\tau)h(t-\tau)d\tau$$

Fourier Analysis

This module transitions signals from the time domain to the frequency domain. You must know how to find the exponential and trigonometric Fourier series coefficients for periodic signals. Practice evaluating the continuous-time Fourier transform (CTFT) of standard signals using transformation properties like time-shifting, frequency-shifting, and differentiation.

Laplace and Z-Transforms

Transforms convert calculus and difference equations into straightforward algebraic problems. Study the region of convergence (ROC) properties extensively. The paper features long questions requiring you to determine the system function $H(s)$ or $H(z)$, find the inverse transform, and deduce the system stability based on the location of poles relative to the ROC.

Answer Writing Strategy for High Marks

RTU evaluators look for step-by-step mathematical derivations, explicitly stated transform properties, and clearly labeled signal plots. Use a blue pen for text explanations, equations, and derivation steps. Use a black pen and ruler for drawing signal waveforms, block diagrams, and pole-zero plots.

In Part A, answer directly. If a question asks for the definition of an energy signal, state clearly that it is a signal whose total energy is finite and non-zero, while its average power is zero.

In Part B, show your mathematical proofs explicitly. When verifying if a system is time-invariant, clearly demonstrate the output due to a delayed input versus the delayed version of the original output to prove your conclusion.

In Part C, mathematical precision is critical. When solving a ten-mark convolution problem, sketch the signals at each step of the shifting process. Clearly write down the integration limits for different time intervals, evaluate the integrals carefully, and draw the final convolved output waveform with exact amplitude and time values.

Time Management During the Exam

Allocate exactly 20 minutes to Part A. Spend 40 minutes addressing the five short-answer questions in Part B. Reserve the remaining 120 minutes for the three long-answer questions in Part C. Evaluating complex integrals, executing algebraic partial fractions, and sketching precise waveforms requires steady focus and significant writing time. This distribution guarantees you 40 minutes per major question, giving you time to double-check your algebraic calculations. Use the final 10 minutes to verify your question numbering, ensure all transform pairs are properly stated, and check that your pole-zero plots match your calculated transfer function denominator.