In summary

Until now we have seen different applications of the frequency analysis

• We can evaluate the different frequencies present in the trace. They can correspond to different processes involved in the generation of the signal
• We can study the components of a signal to define a filter that emphasizes some aspects of the signal
• We can evaluate the modification of the frequencies in time with the spectrogram
• We can detect frequencies not evident in time domain as in the case of the sinusoid masked with noise
• We can study the frequencies that maintain a persistent relation between different signals with coherence.

These are the principal uses of spectral analysis in Clinical Neurophysiology.