User Manual

APPENDIX 22
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Appendix 3 Reference
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Input waveform
Stored
waveform
Waveform assumed by
FFT processing
Rectangular window
Waveform after window
processing
 Window function
When a limited segment of the input signal is captured, a function can be
applied to reduce the leakage error.
This function is called the window function.
To minimize the leakage error, a suitable window should be chosen which
matches the type of input signal.
Possible window types include rectangular, Hanning, exponential, flat-top,
minimum, force, etc. In the 8855, three window functions (rectangular,
Hanning, exponential) are available.
Generally, the rectangular window function is most useful for single
waveforms, the Hanning window function for continuous waveforms, and the
exponential window function for attenuated waveforms.
Rectangular window