Matlab 文檔：https://ww2.mathworks.cn/help/signal/ref/spectrogram.html#bultmx7-x
調用：[~,f,t,ps] = spectrogram(data,opt.window,opt.noverlap,freqRange(1):freqRange(2),sample_freq,'reassigned');
有兩個細節：reassigned 解釋如下：
[___] = spectrogram(___,'reassigned') reassigns each PSD or power spectrum estimate to the location of its center of energy. If your signal contains well-localized temporal or spectral components, then this option generates a sharper spectrogram.
示例：
openExample('signal/ReassignedSpectrogramOfQuadraticChirpExample')
這是我自己花了兩張對比圖，效果如下：
圖1 無reassign選項
圖2 有reassign選項