HP 54520 Series - Page 265

Fast Fourier
Transforms (FFT)
Specifications and Characteristics
Operating Characteristics
Peak Search Peak search automatically snaps cursors to any two
selected peaks located anywhere in the displayed frequency span. You
can select peaks from peak number | up toe peak number 99. Frequency
and dBm are automatically displayed at the bottom of the screen
together with the difference in frequency between the two selected
peaks. Peak search saves time by eliminating the need to manually set
cursors.
Channels or Memories FFTs can be executed on any of the
oscilloscope input channels, or on waveforms stored in any of four
nonvolatile memories.
Variable Sensitivity and Offset Sensitivity and offset (vertical
position) can be controlled to display an optimum view of the spectrum.
Sensitivity is calibrated in dB per division; offset is calibrated in dBm.
Selectable Number of Points You can set the number of points the
oscilloscope uses to calculate the FFT, from 512 to 32,768 (in powers
of 2). Increasing the number of points improves frequency resolution at
the expense of update speed. The point choices available are dependent
on the data being operated upon.
Horizontal Magnify Mode This mode allows you to specify the
frequency that is displayed at center screen, and magnify the
frequency-domain display about that point. Magnification increases as
the number of time-record samples increases. At the maximum of 32,768
points, magnification reduces the displayed frequency span to about 12%
of that in the unmagnified display. Horizontal magnification allows you
to zero in on and expand desired portions of the frequency-domain
display.
Center Frequency Control Enabling horizontal magnification allows
you to set the center of the display to a frequency of interest. The
display is magnified about that point so that you get a closer view.
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