[Kuilin L]

Hello Catherine! I am quite confused about window‘s function and how to calculate the window size and also the relationship between window size and frequency resolution and spectral resolution.

I was reading Chapter 7 in Digital Signal Processing and it talks about the window on page 159. It says that a short stretch of the signal is windowed to yield a short-time spectrum. The size of the window is taken to be the duration of one period, from which the amplitude and phase of the first harmonic (of the window size) are computed. The computation is then repeated for two, three, four, etc. periods, giving amplitude and phase information for the respective harmonics.
And it is exemplified as follows: for a signal sampled at 10 kHz, a 10 ms window yields a spectral resolution of 100 Hz (1,000 samples per 100 msec/10 ms), a 50 ms window gives one of 20 Hz (1,000/50), etc.

I have looked up some information and explanation online but I’m still confused by this. Could you please help me with it? Thanks in advance!

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