Basic FAQ for FFT Analyzer

リアルタイム周波数レンジより低い周波数レンジにおいては、新たにFFT処理する時間窓での時間データが1つ前の時間データと1部だけ同じデータとして処理することが可能となります。このように時間窓を重ねて平均処理することをオーバラップ処理と呼びます。

The extent to which overlap can be achieved depends on the processing capability of the FFT analyzer and the frequency range (or the length of the time window being captured). If the frequency range is around 1 kHz or lower, the initial setting (Max overlap) will not allow for much new time data to be incorporated into the averaging process, so it is necessary to set the amount of overlap. A typical setting for a Hanning window is about 50% overlap.

There are two methods for setting the average processing: average count and average time. If you set it by average time, you can achieve sufficient averaging without worrying too much about the amount of overlap.

	Overlap processing (FFT basic terminology)