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You can use the FFT Zoom option to magnify the FFT spectrum horizontally without changing the sample rate. The
available zoom factors are X1(default), X2, X5 and X10. When the zoom factor is set to X1 and the waveform is
located at the center graticule, the left graticule line is at 0Hz and the right is at the Nyquist frequency.
You magnify the FFT spectrum to the center graticule line when you change the zoom factor. That is, the axis for
horizontal magnification is the center graticule line. Turn the Horizontal Position knob clockwise to move the FFT
spectrum to the right. Push the SET TO ZERO button to position the center spectrum at the center of the graticule.
Vertical Zoom and Position
When the FFT spectrum is being displayed, the channel vertical knobs become the zoom and position controls
corresponding to their respective channels. The VOLTS/DIV knob provides the following zoom factors: X1(default),
X2, X5 and X10. The FFT spectrum is magnified vertically to the marker M (math waveform reference point on the
left edge of the screen). Turn the VERTICAL POSITION knob clockwise to move up the spectrum.
5.3.1.7
Using Cursors to Measure FFT Spectrum
You may use cursors to take two measurements on the FFT spectrum: amplitude (in dB) and frequency (in Hz).
Amplitude is referenced to 0db that equals 1VRMS here. You may use cursors to measure at any zoom factor.
Push the CURSOR button, choose the Source option and then select Math. Press the Type option button to select
between Amplitude and Frequency. Click the SELECT CURSOR option to choose a cursor. Then use the V0 knobs
to move Cursor S and Cursor E. Use the horizontal cursor to measure the amplitude and the vertical cursor to
measure the frequency. Now the display at the DELTA menu is just the measured value, and the values at Cursor S
and Cursor E.
Delta is the absolute value of Cursor S minus Cursor E.
5.4
Trigger Controls
The trigger can be defined through the Trigger Menu and front-panel controls. There are six types of trigger: Edge,
Video, Pulse Width, Alter, Slope and Overtime. Refer to the following tables to find a different set of options for each
type of trigger.
