User Manual

Figure 53: the second page of the record
7.13. Using FFT
A 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
Set dBVrms as vertical scale unit
Set Vrms as vertical scale unit
Zoom
x1
x2
x5
x10
Set multiple x1
Set multiple x2
Set multiple x5
Set multiple x10
Taking the FFT operation for example, the operation steps are as follows:
1. Press MENU key and the function menu appear on the right side of the screen.
2. Press MENU ▲ or MENU ▼ key to select FFT MODE. Five items selectable are available at the bottom of
the screen.
3. Press F1 to turn on/off FFT while FFT is not available in Window setting. On/Off shown means the
corresponding function and the green waveform F is shown in the screen after calculation.
4. Press F2 to switch between CH1 and CH2 and the current status of channel shows on the top left.
5. Press F3 to switch over WINDOW including Hamming, Rectangle, Blackman and Hanning.
6. Press F4 to switch over Format dB and Vrms .
7. Press F5 to zoom in or out the waveform, the magnification includes x1, x2, x5, x10 .
8. If the FFT source is CH1, press red button VOLTS POSITION.
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