Howtosignalprocessing
- What is phase in spectrogram?
- What are the three dimensions of a spectrogram?
- What can be seen in a spectrogram?
- How does a spectrogram differ from an FFT plot?
What is phase in spectrogram?
It makes use of the amplitude values of the Short Time Fourier Transform (STFT) but does not consider the information contained in the phase values. In the phase spectrogram, on the other hand, it is precisely the phase values of the STFT that are processed so that they can be presented graphically and are useful.
What are the three dimensions of a spectrogram?
A common format is a graph with two geometric dimensions: one axis represents time, and the other axis represents frequency; a third dimension indicating the amplitude of a particular frequency at a particular time is represented by the intensity or color of each point in the image.
What can be seen in a spectrogram?
A spectrogram is a visual way of representing the signal strength, or “loudness”, of a signal over time at various frequencies present in a particular waveform. Not only can one see whether there is more or less energy at, for example, 2 Hz vs 10 Hz, but one can also see how energy levels vary over time.
How does a spectrogram differ from an FFT plot?
A spectrogram takes a series of FFTs and overlaps them to illustrate how the spectrum (frequency domain) changes with time. If vibration analysis is being done on a changing environment, a spectrogram can be a powerful tool to illustrate exactly how that spectrum of the vibration changes.
