RIGOL
© 2006 RIGOL Technologies, Inc.
User‟s Guide for DS1000 Series
Using the FFT
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
Figure 2-17 Table 2-6 The FFT menu
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
Rectangle
Hanning
Hamming
Blackman
Display FFT waveform on half screen
Display FFT waveform on full screen
Set “Vrms ” as vertical unit
Set “dBVrms ” as vertical unit
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 dBVrms scale.
The dBVrms scale displays component magnitudes using a log scale.