5.
Press
Center
and specify the FFT spectrum frequency at the display's center vertical grid
line. If this is not in the center of span, the displayed spectrum will not take up the whole
screen.
You can also change the
Span
and
Center
softkeys to
Start Freq
and
Stop Freq
if you
prefer that approach. For example, a span of 200 kHz centered on 150 kHz is equivalent to
start and stop frequencies of 50 and 250 kHz.
You can also press
More FFT > Auto Setup
to set the
Span
and
Center
to values that will
display the entire available spectrum.
6.
Press
More FFT
to go to the second page of FFT parameters.
7.
Press
Window
and select the window to apply to the FFT input signal:
Hanning —
accurate frequency measurements and resolving two close frequencies.
Flat Top —
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
Blackman-Harris —
reduced time resolution compared to a rectangular window, but
improved capacity to detect smaller impulses due to lower secondary lobes
8.
Press
Vertical Units
and choose Decibels or V RMS.
To make cursor measurements, press
[Cursors] > Source > Math N
. Use the X1 and X2 cursors
to measure frequency values and difference between two frequency values (AX). Use the Y1 and
Y2 cursors to measure amplitude and amplitude difference (
Δ
Y).
To make other measurements, press
[Measure] > Source > Math N
. You can make peak-to-
peak, maximum, minimum, and average dB measurements on the FFT waveform. You can also
find the frequency value at the first occurrence of the waveform maximum by using X at Max Y.
Keysight IntegraVision PA2200 Series Power Analyzers Operating and Service Guide 153
