Stepped Frequency Sweep

A stepped swept-sine measurement steps through a set of frequencies. A stepped swept-sine measurement includes dynamic measurement for the stimulus level, response level, frequency response, total harmonic distortion (THD), and individual harmonic distortion.

The following figure shows the process for a stepped swept-sine measurement.

Figure 68. Stepped Swept-Sine Measurement Process

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A stepped swept-sine measurement provides a larger dynamic range over an FFT-based measurement because you can optimize the signal level and input ranges at each test frequency. You can test arbitrary frequency resolutions that are linear, logarithmic, or adapted to the dynamic response of the device under test (DUT). When the frequency resolution is adapted to the dynamic response of the DUT , you can test more frequencies in regions where the dynamic response is of interest to the application. The main benefit of a stepped swept-sine measurement is the ability to measure harmonic distortion with a linear response simultaneously. An FFT-based measurement offers a speed advantage for broadband measurements with multiple test frequencies.