User Manual

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analyzing the input signal on Oscilloscope. You can match these frequencies
with known system frequencies, such as system clocks, oscillators, or power
supplies.
Taking the FFT operation for example, the operation steps are as follows:
1. Press the Math button to display the math menu in the bottom. The blue M
waveform appears on the screen.
2. Select FFT in the bottom menu.
3. Select Source in the right menu; select ① in the left source menu.
4. Select Window in the right menu; select the proper window type in the left
menu.
5. Select Format as Vrms or dB in the right menu.
6. Select Horizontal in the right menu; select repeatedly to make the
symbol in front of Hz, turn the G knob to adjust the horizontal position of
FFT waveform; then select to make the symbol in front of the Hz/div
below, turn the G knob to adjust the time base of FFT waveform.
7. Select Vertical in the right menu; do the same operations as above to set
the vertical position and voltage division.
To select the FFT window
■ There are 6 FFT windows. Each one has trade-offs between frequency
resolution and magnitude accuracy. What you want to measure and your
source signal characteristics help you to determine which window to use. Use
the following guidelines to select the best window.
Type
Characteristics
Window
Rectangle
Best solution for frequency, worst for magnitude.
Best type for measuring the frequency spectrum of
nonrepetitive signals and measuring frequency
components near DC.
Recommend to use for:
 Transients or bursts, the signal level before and
after the event are nearly equal.
 Equal-amplitude sine waves with frequencies those
are very close.
 Broadband random noise with a relatively slow
varying spectrum.