CF-5200 Frequently Asked Questions

Overall (abbreviated as OA) is the sum of the products of the power values (Y-axis values) for all frequencies analyzed using FFT.

Please note that a low-pass filter is applied, so components above the specified frequency range will be cut off.

First,
When the data length is 2048 (default setting), the screen displays 801 spectra, which are 0Hz + 800 = 801, representing the frequency range divided into 800 equal parts.
i = 0 to 800
Vi = Voltage amplitude of the i-th spectrum

Therefore, the values of each spectrum displayed on the screen are

(1) In log display (when the Y-axis is displayed in dB)

Pi=10LOG（Vi）²

(2) In Lin display (when the Y axis is in Vr display)

√（Vi）²＝Vi

The Pi and Vi are displayed.

The calculation for overalls is

(3) When the Y-axis is logarithmic

Let P0 be the Y-axis value (dB) of the DC component and Pi be the i-th Y-axis value (dB).

（OA）＝10LOG｛（10^P0／10＋--＋10^Pi／10＋10^P800／10）Hf｝

Hf: Window Correction
In Rectangular 1
In Hanning, 2/3

(Example) If Pi = 30, 50, ---40 (dB)
(Values that can be read when the Y-axis is displayed in dB)

（OA）＝10LOG｛（10^30/10＋10^50／10＋--＋10^40/10）Hf｝

(4) When the Y-axis is LIN

V0: Y-axis value of the DC component
Let Vi be the i-th Y-axis value (Vr).

（OA）LIN＝√｛（V0²＋--＋Vi²＋V800²）Hf｝

Note: The contents within { } are inside the root.

(Example) If the values are 0.1, 0.3, ---0.4 (V)

（OA）LIN＝√｛（0.1²＋0.3²＋−−−＋0.4²）Hf｝

Calculating Pi and Vi within any range will give you the partial overall.
In the time domain, this corresponds to the mean square of 2048 data points.