Math Functions - Agilent Technologies 8560E User Manual

Math Functions

The analyzer processes and stores measurement results that can be
displayed or manipulated arithmetically.
This section describes the internal processing of traces and tells how to
manipulate data correctly with the math commands.
Variables and Traces
The analyzer processes all information as variables and trace arrays.
For example, the analyzer reserves an area in memory for trace A
information. Whenever trace A is swept, the analyzer updates that
memory area with new data. The analyzer also has space in memory for
variables. Whenever a marker is placed on a trace, the analyzer assigns
the amplitude value to the variable, MKA (marker amplitude).
Variables
Variables exist permanently in the analyzer memory. The CF (center
frequency) command and SP (frequency span) command are examples
of variables.
Traces
Traces consist of a series of data points that contain amplitude
information. Two separate traces can be swept: trace A or B. These are
the predefined traces that exist permanently in the analyzer memory.
Traces A and B each have preset lengths of 601 data points.
Math Commands
Math commands are data-manipulating functions that modify traces or
return modified data to the computer.
Two Rules for Trace Math
Special consideration must be exercised when using math commands
with traces. Otherwise, these data-manipulating commands can yield
inaccurate results. Follow these two rules to obtain accurate results:
1. Avoid truncation of data. Be sure that the destination length is equal
to or greater than the source length.
2. Remember that the analyzer limits numbers greater than 600 (610
with overrange) and less than 0 (slightly above the top and at the
bottom graticule, respectively), when operating with trace elements.
Math operations are restricted to the legal range of measurement units
when trace arrays form the destination or source.
Chapter 5
Programming
Math Functions
319