Signal Processing · 101
Sampling is a deal with time
Aliasing is what happens when your samples lie about the continuous world.
The question
Why does undersampling invent frequencies that were never there?
What clicked
Sampling isn’t just “taking points.” It’s committing to a grid in time. If the signal wiggles faster than that grid can honestly represent, those wiggles masquerade as slower ones — aliasing.
Pitfalls
- Memorizing Nyquist as a slogan without picturing the fold
- Assuming more samples always mean “more truth” without asking of what
Keep this
Ask: “What is the fastest change I care about, and does my sample rate keep that promise?”