User Manual

22. Using FFT function
An FFT breaks down signals into component frequencies, which the oscilloscope uses to display a graph of
the frequency domain of a signal, as opposed to the oscilloscope’s standard time domain graph. You can
match these frequencies with known system frequencies, such as system clocks, oscillators, or power
supplies.
FFT in this oscilloscope can transform 2048 points of the time-domain signal into its frequency components
and the final frequency contains 1024 points ranging from 0Hz to Nyquist frequency .
The following table describes the FFT menu:
Function Menu
Setting
Instruction
FFT
ON
OFF
Turn on FFT function.
Turn off FFT function.
Source
CH1
CH2
Select CH1 as FFT source.
Select CH2 as FFT source.
Window
Rectangle
Blackman
Hanning
Hamming
Select window for FFT.
Format
dB
Vrms
Select dB for Format.
Select Vrms for Format.
Zoom
*1
*2
*5
*10
Set multiple *1.
Set multiple *2.
Set multiple *5.
Set multiple *10.
Taking the FFT operation for example, the operation steps are as follows:
1. Press the MATH MENU button and call out the WAVE MATH menu.
2. Press F1 to turn on/off FFT after entering FFT menu, and please note that FFT is prohibited in Window
setting mode. The green waveform F is shown in the screen after calculation.
3. Press F2 selection button to switch over source channel CH1 and CH2.
4. Press F3 button to select WINDOW, including Rectangle, Hamming, Hanning and Blackman.
5. Press F4 to choose the Format as dB or Vrms.
6. Press F5 to zoom in or out the wave of the multiple including *1, *2, *5, *10.
7. Adjust the “Horizontal” knob in horizontal control zone to move the waveform and the shown frequency of
M Pos is the exact frequency of the cursor point in the middle of spectrum.
8. Turn off FFT and then press math menu button to go back to the second page of wave math.
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