Number Of Points For Smoothing - Agilent Technologies ESA-E Series Programmer's Manual

Language Reference
TRACe Subsystem
Increasing the number of points increases smoothing at
the cost of decreasing resolution.
The amount of smoothing decreases at the endpoints.
Because :TRACe:MATH:SMOoth <trace> averages
values that occur before and after the data point in
time, display irregularities can be caused at the start
and stop frequencies. To avoid possible irregularities
(signal distortion) at the ends of the trace, use small
values for the smooth parameter.
Refer to
smoothing phenomena. With 31 smoothing points and a
401 point trace, point 16 will be the first point to have
full 31-bucket smoothing. Likewise, point 385 will be
the last point with full 31-bucket smoothing. Under the
conditions stated, points 2 through 15 will be smoothed
as follows: Point 2 is derived from averaging buckets 1
through 3. Point 3 is derived from averaging buckets 1
through 5, Point 4 is derived from averaging buckets 1
through 7, and so forth until point 16 is reached. The
quantity of buckets used for the smoothing running
average increases at the rate of 2 buckets per point,
from point 1 to point ([smoothing number/2] + 1), at
which time the full number of smoothing points is
utilized. The same characteristic occurs at the end of
the trace, beginning at point 386, when the number of
averaging buckets begins to decrease until point 401 is
reached.
By replacing the value of each point in a trace with the
average of the values of a number of points centered
about that point, any rapid variations in noise or
signals are smoothed into more gradual variations. It
thereby performs a function similar to reducing the
video bandwidth without the corresponding changes in
sweep time; as such, frequency resolution is decreased.
Also, signal peaks are reduced with large smoothing
values; and this can cause the amplitude to appear to
be less than its actual value.

Number of Points for Smoothing

:TRACe:MATH:SMOoth:POINts <integer>
:TRACe:MATH:SMOoth:POINts?
Specifies the number of points that will be smoothed in
:TRACe:MATH:SMOoth. See that command for an explanation of how
smoothing is performed.
5-140
Figure 5-1 for a discussion of this end-point
Chapter 5