User Manual

80
Window
Characteristics
Applications
Rectangle
The best frequency
resolution, but the poorest
amplitude resolution. Similar
to when no window is
applied.
Transient or short pulses. Sine
waveform with the same amplitude
and rather similar frequencies. Wide
band random noise with relatively
slowly changing waveform spectrum.
Hanning
Better frequency resolution;
poorer amplitude resolution.
Sine, periodic and narrow band
random noise.
Hamming
Somewhat better frequency
resolution than Hanning.
Transient or short pulse, the signal
levels before and after the
multiplication are rather different.
Blackman
The best amplitude
resolution; the poorest
frequency resolution.
Single frequency signal, search for
higher order harmonics.
Table 7 - FFT window instructions
5. Press the Center softkey and turn the Universal Knob to set the frequency of the center
vertical line.
6. Press the Hz/div softkey and turn the Universal Knob to set the vertical range of the display.
7. Press the FFT Zoom softkey and turn the Universal Knob or turn the horizontal scale knob to
select the desired magnification (1X, 2X, 5X, 10X). Set the FFT Zoom to a higher magnification
to see more details of the FFT waveform.
8. Press the Scale softkey to select the units per division for the vertical axis. The units of the
vertical axis can be dBVrms (logarithmic) or Vrms (linear). If you need to display the FFT
frequency spectrum with a large dynamic range, dBVrms is recommended.
9. Press the Reference Level softkey and turn the Universal Knob to adjust the position of the
FFT's vertical position.
10. Press the Unit softkey and turn the Universal Knob to display with a Vrms (linear) or dBVrms
(logarithmic) vertical scale.
11. Press the Display softkey to select Split, Full Screen, and Exclusive display mode.
 Split: the source channel and the FFT operation results are displayed separately. The time
domain and frequency domain signals are displayed on separate portions of the screen.
 Full Screen: the source channel and the FFT operation results are displayed in the same
window to view the frequency spectrum more clearly and to perform more precise
measurements.
 Exclusive: only the FFT operation results are displayed in full screen.