Learning Forum

[LMZ]

Take the offcial example in interconnect, OSC_RFSA.icp, which is about how to set parameter in RFSA.

What's the relationship between signal and spectrogram?

How to use and understand the spectrogram under different spectrogram time window(t1) and spectrogram time overlap(t2)? Below are the results from spectrogram under different t1 and t2.

[LMZ]

The signal result is two frequencies with different power, shown as below.

[Kyle]

The "signal" result is the spectrum of the signal recorded during the entire duration of the simulation. The spectrogram will take the signal from a certain time window and find the spectrum from only that time window. The duration of the time window is set by the "spectrogram time window" property. The subsequent time windows used by the spectrogram will overlap with eachother, with the amount of overlap set by the "spectrogram time overlap" property. The "signal" result is more commonly used, the spectrogram is typically used for more specialized analysis.

[LMZ]

Hello @kj88 Thanks for reply. Do "spectrogram time window" and"spectrogram time overlap"have same meaning for OSA(optical spectral analyzer)?
Different current depends on time is applied on DFB,the "spectrogram" results is as below. Why the wavelength dependence with time is sysmetric? The "signal "result is correct with different lasing modes.