Key takeaways
- Eight units, from signal classification to a comparison of all transforms.
- Periodicity rules and system property checks are shown with quick examples.
- Fourier series symmetry shortcuts and the main Fourier transform pairs are tabulated.
- Laplace and Z-transform pairs are given with their ROC, plus the sampling theorem and aliasing.
- Original Uncodemy revision notes, not official university notes. Check your own syllabus.
About these handwritten notes
These Signals and Systems notes are original Uncodemy revision notes, written in a clean handwritten style so they are quick to read before an exam. They follow the common B.Tech syllabus for Signals and Systems (B.Tech ECE and EEE, and GATE EC basics). They are not official university notes and not copied from any textbook or past paper.
Topic order, unit numbers and depth vary between universities, so first place each unit below against your own university syllabus. If your syllabus has a topic that is missing here, add it in the margin from your class notes or textbook. Use these notes for revision after you have studied the topic once in class, not as your only study material. They are short on purpose: the aim is to help you recall the main ideas, formulas and diagrams quickly, so that your exam time goes into writing good answers.
What's inside the Signals and Systems notes
The notes follow the usual teaching order, from time-domain ideas to the four transforms and sampling. Transform tables and ROC sketches are drawn so you can copy them into a formula sheet.
- Unit 1: Signals: Basics and Classification. Continuous and discrete, periodic, even and odd, energy and power signals, standard signals and signal operations.
- Unit 2: Systems and Their Properties. Linearity, time invariance, causality, stability and memory, LTI systems, impulse response and convolution.
- Unit 3: Fourier Series. Trigonometric and exponential series, coefficients and symmetry shortcuts.
- Unit 4: Fourier Transform. Important transform pairs, properties and Parseval's theorem.
- Unit 5: Laplace Transform. Common pairs with ROC, properties, and causality and stability from the ROC.
- Unit 6: Z-Transform. ROC, properties, inverse Z-transform and system functions from difference equations.
- Unit 7: Sampling. Sampling theorem, Nyquist rate, aliasing and the types of sampling.
- Unit 8: Comparison of Transforms. When to use Fourier series, the Fourier transform, Laplace and Z, in one table.
The last page of the PDF lists the most asked practice questions for the whole subject, so you can test yourself after finishing all the units.
Formulas and solved examples in the PDF
Formula boxes cover periodicity rules, energy and power, the convolution sum and integral, Fourier coefficients, Parseval's theorem and the main transform pairs. Solved examples include the period of cos(4t) + sin(6t), a discrete-time convolution, the energy of e^(-at)u(t), a system function from a difference equation and the Nyquist rate for a two-tone signal.
How to revise Signals and Systems with handwritten notes
Handwritten-style notes work best when you read actively. Keep a pen and a rough notebook beside you, cover the formula or diagram, and try to write it yourself before you look.
- Build your own one-page transform table with Fourier, Laplace and Z pairs and their ROC. Recite it until it is automatic.
- Practise system property checks on four or five short systems. Each takes under two minutes once you know the tests.
- For discrete convolution, use the table method and check that the output length is N1 + N2 - 1.
- For every Laplace or Z-transform answer, write the ROC as well. An answer without it is often marked as incomplete.
In the last week, read only the formula boxes and exam tips, and solve one numerical or long question per unit from memory. If you study with friends, ask each other to explain one diagram or derivation aloud. Explaining a topic is the fastest way to find the gaps in it.
A short revision plan
If your exam is about a week away, this plan covers every unit in the PDF once and leaves time for practice. Stretch it over two weeks if you are starting from scratch.
- Day 1: Signals: Basics and Classification, Systems and Their Properties.
- Day 2: Fourier Series, Fourier Transform.
- Day 3: Laplace Transform, Z-Transform.
- Day 4: Sampling, Comparison of Transforms.
- Day 5: Solve the practice questions in the exam focus section below, one per unit, without the notes.
- Day 6: Read only the formula boxes and exam tips, redo the numericals you got wrong, and sleep early.
Common mistakes to avoid
- Calling a discrete-time sinusoid periodic without checking that ω/2π is rational.
- Forgetting the ROC, so the same X(s) or X(z) is matched to the wrong signal.
- Writing the Nyquist rate as the highest frequency instead of twice the highest frequency.
- Mixing up time scaling and time shifting order when sketching x(at + b).
How Signals and Systems links to other subjects
Signals and Systems uses calculus, complex numbers and the Laplace transform from Engineering Mathematics. It is the base for Digital Signal Processing, Control Systems, Analog and Digital Communication, and image processing electives.
Exam focus: high-weightage topics
University papers usually give the most weight to system properties, convolution, Fourier series and Fourier transform properties, Laplace and Z-transforms with ROC, and the sampling theorem. Periodicity, ROC and Nyquist rate are common short questions.
Typical long and numerical questions to practise:
- Check linearity, time invariance, causality and stability of y(t) = t x(t) and y[n] = x[2n].
- Find the fundamental period of a sum of sinusoids in continuous and discrete time.
- Compute the convolution of two finite discrete-time sequences and two continuous-time signals.
- Find the Fourier series of a square wave and a sawtooth wave.
- Find the inverse Z-transform by partial fractions for all possible ROCs.
- State the sampling theorem and explain aliasing with spectra.
When you write a long answer, start with a one-line definition, draw the diagram or circuit, write the derivation in clear steps and end with the final result and its unit. For numericals, write the formula first, then substitute, so you can still earn step marks if the arithmetic slips.
These are practice questions based on common syllabus topics. They are not verified past papers, and we do not claim any question will appear in your exam. For real previous papers, use your university's official archive.
Who these notes are for
These notes are for B.Tech ECE and EEE students preparing for their Signals and Systems semester exam, and for students revising GATE EC and EE basics such as system properties, periodicity, ROC, convolution length and Nyquist rate. Students heading towards DSP, communication or data science work also benefit from a solid grip on this subject.
Download Signals and Systems Handwritten Notes PDF
Signals and Systems Handwritten Notes PDF
The PDF carries the same content as this page in a clean, print-ready layout, so you can read it offline and keep it for revision.
8 pages · 300 KB · PDF · Updated 5 Nov 2026