What types of time window functions are available and how can they be used according to the purpose?

The practical method for reducing a leakage error is to apply weighting so that the beginning and the end of the time window that is to be cut out are zeroed smoothly. Such weighting function is referred to as a time window function. The window function that is most generally used by the FFT analyzer is a Hanning window.

 

Table1 Typical window functions used by the FFT Analyzer

 

Type Equivalent noise bandwidth Level accuracy Main application
Rectangular Δf -3.9 dB Transient signals
Hanning 1.5 Δf -1.42 dB General signals and continuous signals
Flat top

3.6714 Δf

±0.1 dB Periodic signals

 

 

Revised:(2009/11/16)



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