STUDY GUIDE · GKU 4
Signals and systems study guide (Electrical Engineering)
Signals and systems is the mathematics of what a signal contains and what a system does to it. A periodic signal can be decomposed into harmonics, a non-periodic one into a continuous spectrum, and a discrete-time one into a sequence acted on by difference equations. The same three ideas — Fourier series, Fourier transform and sampling — connect the time domain to the frequency domain and explain why a digital system can process an analog signal without losing information. The second half treats linear time-invariant systems: convolution in time, multiplication in frequency, transfer functions, and the analog and digital filters built from them. Every section opens with a quick-revision card, and the worked examples run from easy to exam level.
Structured by the official ETEC subject standard for this topic: every listed topic and learning outcome, with formulas, figures and worked examples. The full sections are available to members in the app.
SKU 4.1 · Signal transformations
Fourier series
Decomposing a periodic signal into a DC term and harmonics, the coefficients, and the power carried by each harmonic.
Fourier transform and the Z-transform
The continuous spectrum of a non-periodic signal, the transform pairs worth knowing, and the discrete-time Z-transform with difference equations.
Sampling and reconstruction
The Nyquist rate, aliasing, the aperture effect, and the resolution of a discrete spectrum.
SKU 4.2 · Linear time-invariant systems
LTI systems and filters
Convolution, transfer functions, impulse and frequency response, and the analog and digital filters built from them.