Reviewer for Signals & Digital Signal Processing in Computer Engineering.
Signals & Systems
Signals carry information over time. They can be analog (continuous) or digital (discrete).
Sampling
The Nyquist theorem states the sampling rate must be at least twice the highest signal frequency to avoid aliasing.
Sampling below the Nyquist rate causes aliasing — the signal is distorted and cannot be recovered.
Transforms & Filters
The Fourier Transform converts time-domain signals to frequency-domain. Filters (low-pass, high-pass, FIR, IIR) remove unwanted frequencies.
Worked Example
A signal’s highest frequency is 4 kHz. Minimum sampling rate?
Below 8 kHz, aliasing distorts the signal and the original cannot be recovered. This is why audio CDs sample at 44.1 kHz — comfortably above twice the ~20 kHz limit of human hearing.
Before your exam, make sure you can confidently explain and apply each of the following:
- Signals & Systems
- Sampling
- Transforms & Filters
- Worked Example
Re-read any section above where you hesitate.