FFT for Audio and RF Spectrum Analysis Using an Oscilloscope
Boasting front ends with 70 μVrms noise floor @ 200 MHz bandwidth, Siglent's 12-bit HD oscilloscope models are an excellent choice for analyzing and troubleshooting signals in the both the audio and RF spectrums.
Jim Wilson
Last Update setahun yang lalu
Models: SDS800X HD, SDS1000X HD, SDS2000X HD, SDS3000X HD
Note: this tip also applies to 8-bit models: SDS2104X Plus, SDS5000X, SDS6000A, SDS7000A
To display an input signal along with the FFT, choose one of the four functions from the Math menu and then click in the Function field to open the Function dialog.
Click in the Function field to open the Function dialog and choose FFT from the Freq-Analysis tab (or Basic tab) and close the dialog box
The Math Menu with FFT function is shown in the figure below:
Config Formats how the FFT is displayed. You can choose from a list of Window Functions including Rectangle, Blackman, Hanning, Hamming, and Flattop. You can also select from Display options to show the input signal with the FFT or just the FFT on the screen. Options for FFT Mode are: Normal, Max-Hold and, and Average.
Vertical allows you to choose Units (Vrms, dbVrms, and dBm), Scale, and Reference Level
Horizontal allows you to configure the sweep. Sweep Mode: Linear or Decade and frequency settings: Center, Span, Start, and End.
The Tools menu contains Peaks and Markers options that help to display and analyze the results.
In the figure below, FFT is demonstrated using an input signal of 100mVpp 20kHz sinewave on our SDS1104X HD oscilloscope.
