About Math Operations - Keysight N9912A User Manual

How to display data and memory traces
 Press Trace
 Then
How to perform Trace Math
Trace math is performed between a live trace and a memory trace. When one of the
following math operations are selected, the yellow data trace displays the current
measurement with the selected trace math applied. The math operation symbol
indicated below in [brackets] is displayed on the lower left corner of the screen.
 Press Trace 6.
 If not already stored, press
 Then
 Then choose one of the following:

About Math Operations

Data / Memory and Data - Memory math operations are performed on complex
linear data before it is formatted. Because data is often viewed in log format, it is not
always clear which of the two math operations should be used. Remember: dividing
linear data is the same as subtracting logarithmic data. The following illustrates, in
general, when to use each operation.
Use Data / Memory for normalization purposes, such as when comparing traces
"before" and "after" a change is made or when measuring trace noise. In the
following table, the Data/Mem values intuitively show the differences between
traces. It is not obvious what Data-Mem is displaying.
Use Data - Memory to show the relative differences between two signals. Use for
comparison of very small signals, such as the S11 match of two connectors.
160
6.
to store the current live trace into memory. A 'beep' sounds to
Data->Mem
confirm the data trace has been saved to memory. There is no display annotation
that indicates that the memory trace has been stored.
Press to view only the data trace.
Data
o
Press to view only the memory trace.
Memory
o
Press
Data & Memory
o
memory.
Data Math.
[D+M] Current measurement data is added to the data in
Data + Memory
o
memory.
[D-M] Current measurement data is subtracted from the data
Data – Memory
o
in memory.
[D/M] Current measurement data is divided by the data in
Data / Memory
o
memory.
[Data] Displays trace data with NO math applied.
Math Off
o
Values to compare
0.5 dB and 0.6 dB
0.5 dB and 0.7 dB
to view both the live trace and the stored memory trace.
to store the current live trace into
Data->Mem
Data/Mem
0.1 dB
0.2 dB
Data-Mem
-39 dB
-33 dB
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