Noise spectral density
Noise is frequency-dependent and should be matched to the sensing sequence.
$$S_B(\omega)=\int_{-\infty}^{\infty}C_B(\tau)e^{-i\omega\tau}d\tau$$
Physical intuition
Noise is frequency-dependent and should be matched to the sensing sequence.
Deep dive: physical mechanism
The autocorrelation of fluctuations determines spectral power, while the sensor filter function selects frequencies that affect the measured phase.
What is measured experimentally?
Measure a power spectrum or coherence decay curve.
Assumptions, noise and limitations
Stationarity assumptions can fail for drift and non-Gaussian noise.
Research and simulation exercise
Compare white and 1/f noise in synthetic sensor time traces.
Connect the ideas
Explore the chapter overview, learning path, and references.