Keysight Technologies 53150A - Page 54

1 Getting Started
54 Keysight 53150A/151A/152A Operating Guide
When the Counter interpolates for frequencies that are above or below the range
of frequencies specified in the currently selected profile, it never computes a value
that would fall on the opposite side of the zero axis from the closest specified
frequency. In other words, if there are two or more data points that contain loss
values, the Counter never computes or applies a correction that would be
indicative of gain. Conversely, if there are two or more data points that contain gain
values (negative loss values), the Counter never applies a correction that would be
indicative of loss. Since there can be no further change in the loss or gain values
once the zero axis is reached, no power corrections are applied when the input
frequency reaches or passes a point in the profile that intersects the zero axis.
Effectively, the Counter computes only loss-correction values or
gain-correction values—never both within the same profile.
When you enter values in power-correction data points and then exit the
data-point display (using either the left-arrow key or the Enter key), the Counter
immediately sorts all of the data-points into order by the frequency values.
Therefore, if you enter a pair of values in a data point, exit the data-point display,
and then immediately return to the display for that data point, you may see
different values than the ones you just entered. The values you entered may now
be contained in a differently numbered data point in the same profile, if they were
previously entered out of order by frequency.
Increasing Profile Accuracy
To increase the accuracy of a power-correction profile, you can add data points
between the existing data points in the profile (if less than 10 data points are in
use), thus bringing the data points closer together and shortening the
straight-line segments. If all ten data points are in use, you can add data points by
using two or more profiles for a single test configuration. If you do this, you must
select the profile you need (from the Menu) for the range of frequencies being
measured. This means that you must select a different profile whenever the
measured frequency moves outside the range of frequencies defined by the data
points in the currently selected profile.
NOTE
As the graph shows, the Counter never computes power-correction values for
loss above the zero axis. Conversely, corrections are never computed for gain
below the zero axis. Once the correction value reaches the zero axis, no further
corrections are applied.