Signal Classifications in DSP

Signal Classification: The Taxonomy of DSP

Before we can process signals, we must understand their nature. Signals fall into several fundamental categories:

Classification	Description	Examples
Continuous-Time vs Discrete-Time	Defined for all time vs. only at discrete instants	Analog audio vs. sampled digital audio
Continuous-Valued vs Discrete-Valued	Any amplitude value vs. restricted to finite levels	Analog voltage vs. quantized digital values
Deterministic vs Random	Predictable by formula vs. requiring probability theory	Sine wave vs. speech/noise
Stationary vs Non-Stationary	Constant statistical properties vs. changing over time	Pure tone vs. speech/music
1D vs Multidimensional	Single independent variable vs. multiple	Audio (time) vs. Image (x,y)
Single-Channel vs Multichannel	One source vs. multiple simultaneous sources	Mono audio vs. 3-lead ECG

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