Iwatsu DS-8814, Operation Manual

Page: 122 / 141

F-9
Lets take a measurement !
To correctly perform an FFT, the waveform must be appropriately displayed with the
normal time axis (YT) display screen.
Procedure
(1) Connect the signal to be observed to the CH1
input. With Length from the DISPLAY menu
set to Short, press the AUTOSET button to
execute AUTOSET. In the figure to the left, a
100kHz, 0.6V sine wave is being input.
(2) As necessary, adjust the VOLT/DIV and
OFFSET knobs so that the amplitude of the
waveform fits within the screen. In this
example, since an appropriate state has been
set by AUTOSET, there is no special
adjustment.
Similarly, adjust the TIME/DIV and DELAY
knobs so that the portion of the waveform to be
measured fits within the screen. In the case of
a repeating waveform, as shown in the figure
to the left, several cycles of the waveform are
included within the screen.
(3) When FFT is selected by Math of the
DISPLAY menu,+ an FFT is executed and the
waveform displayed, In this state, if the
TIME/DIV knob is pressed, the time axis (YT)
waveform of (2) is displayed. If the
TIME/DIV knob is pressed again, the FFT
waveform is displayed.
Horizontal axis sensitivity ( /div)
Vertical axis
sensitivity (dBm/div) FFT sampling frequency