# FFT Frequency

The FFT Frequency measurement measures the frequency of a peak on an FFT function waveform. See FFT Operator.

You can choose a peak by using these controls (when you add or edit the measurement):

- Peak Number — Defines which of the peaks, counting from the left of the display, you want to make FFT measurements on. A peak must exceed the Peak Level threshold to be counted as a peak.

- Peak Level — Defines the threshold an FFT peak must cross to be considered a peak. The default Peak Level is -40 dBm.

## To measure

1. Click the toolbar's FFT tab.

2. If necessary, click the toolbar's More buttons to locate the FFT Frequency button.

3. Click the button.

4. In the FFT Frequency dialog box, select the FFT function waveform on which to make the measurement.

5. Enter the Peak Number and Peak Level options to identify the peak you want to measure.

6. Click Apply.

## SCPI Command

`:MEASure:FFT:FFRequency`