Agilent Technologies InfiniiVision 6000 Series, Руководство пользователя, Страница: 226 / 368

226 6000 Series Oscilloscope User’s Guide
5 Making Measurements
• Center — sets the FFT spectrum frequency represented at
the center vertical grid line of the display. It is possible to
set the Center to values below half the span or above the
maximum available frequency, in which case the displayed
spectrum will not take up the whole screen. Press the
Center
softkey, then turn the Entry knob to set the desired
center frequency of the display.
• Preset — sets the frequency Span and Center to values that
will cause the entire available spectrum to be displayed.
The maximum available frequency is half the effective FFT
sample rate, which is a function of the time per division
setting. The current FFT sample rate is displayed above
the softkeys.
2 Press the More FFT softkey to display additional FFT
settings.
• Window — selects a window to apply to your FFT input
signal:
•
Hanning
— window for making accurate frequency
measurements or for resolving two frequencies that are
close together.
•
Flat Top
— window for making accurate amplitude
measurements of frequency peaks.
•
Rectangular
— good frequency resolution and amplitude
accuracy, but use only where there will be no leakage
effects. Use on self-windowing waveforms such as
pseudo-random noise, impulses, sine bursts, and
decaying sinusoids.
FFT Scale FFT Offset Return to
previous menu
Window