Tonal Detection

Introduction False tonal detection is one of the most common structural failure modes in automated DSP pipelines. In noisy environments, PSD estimators frequently produce spurious peaks caused by: estimator variance leakage ripple random noise bursts If filters are synthesized directly from these peaks, systems end up suppressing noise instead of interference. As shown in: Why PSD Peak Detection Fails in Low SNR Signals How STFT Cross-Validation Improves Low-SNR Tone Detection frequency magnitude alone is insufficient for deterministic detection. ...

Introduction In low-SNR environments, PSD-based peak detection often becomes unstable. Spectral variance, leakage, and noise ripple cause dominant frequency bins to shift randomly between measurements. As discussed in Why PSD Peak Detection Fails in Low SNR Signals, the core issue is not mathematical correctness — it is the loss of determinism. Short-Time Fourier Transform (STFT) introduces temporal structure into spectral analysis, enabling engineers to separate true tonal interference from stochastic noise behavior. ...