Rigol DS1302CA User Manual page 43

1. FFT Analyse
The FFT (Fast Fourier Transform) process converts a time-domain signal into its
frequency components mathematically. FFT waveforms are useful in the
following applications:
Measuring harmonic content and distortion in systems

Characterizing noise in DC power supplies

Analyzing vibration

Press MATH→Operate→FFT to enter FFT setting menu.
Figure 2-17 Table 2-7 The FFT menu
Key points for FFT
1. Signals that have a DC component or offset can cause incorrect FFT
waveform component magnitude values. To minimize the DC component,
choose AC Coupling on the source signal.
2. To reduce random noise and aliases components in repetitive or
single-shot events, set the oscilloscope acquisition mode to Average.
3. To display FFT waveforms with a large dynamic range, use the dBV
scale. The dBV
User‟s Guide for DS1000CA Series
Menu
Settings
A+B
A-B
Operate
A× B
FFT
CH1
Source
CH2
Rectangle
Hanning
Window
Hamming
Blackman
Split
Display
Full screen
V
RMS
Scale
dBV
RMS
scale displays component magnitudes using a log scale.
RMS
Comments
Add source A to source B.
Subtract source B from source A.
Multiply source B by source A.
Fast Fourier Transform.
Define CH1 or CH2 as FFT source.
Select window for FFT.
Display FFT waveform on half screen.
Display FFT waveform on full screen.
Set "V " as vertical unit.
RMS
Set "dBV " as vertical unit.
RMS
RIGOL
RMS
2-15