HP 54710A User's Reference Manual page 329

FFT Menu
Oscilloscopes display signals in the time domain. When an FFT, or
fast Fourier transform is added to an oscilloscope, signals can also be
displayed in the frequency domain. The frequency domain allows you
to see the frequency content of a signal. FFT functionality added to
an oscilloscope allows you to analyze a signal from two different, but
complimentary points of view, the frequency domain and the time
domain.
Figure 21-1
FFT menu and menu map
This softkey is displayed when the top softkey, Display, is set to on.
To enter the FFT menu
Press the blue shift key on the keypad, then press the Math hardkey.
21–2