: SDSP primarily focuses on signals represented as indexed sequences of real or complex numbers,
: While deterministic signals (like a pure sinusoid) are mathematically precise, real-world signals are typically stochastic—they contain inherent randomness and noise that requires statistical modeling.
: Many signals are "quasi-stationary" over short durations (e.g., 20–40ms segments of speech) but non-stationary over longer periods, necessitating adaptive modeling techniques. Key Signal Modeling Techniques