Trace Math Capabilities - Anritsu MS2024B Manual

VNA Display Overview
You can touch and hold to place the active marker, or you can slide your finger to drag the
marker along a trace. Your touch point represents a location on the x-axis, and this touch
point may be anywhere on the y-axis, or even within the Marker Table when it is
displayed (On).
Note that when Marker Table is displayed with a zero span (start frequency = stop
Note frequency), the marker frequency is labeled with the trace point number in
parenthesis. For example: MK1 500 kHz(101) –4.99 dB
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Trace Math Capabilities

Trace math is a powerful tool for comparing two traces to each other by using mathematical
operations. To perform trace math, select the trace menu (by pressing the Shift key and the
Trace (5) key), and then select the active trace. Press the Save Trace to Memory soft key to
save a copy of the trace into the instrument memory. When trace TR1 is saved to memory, an
M1 memory trace is produced. Each trace can have one associated memory trace.
You can display Trace Only, Memory Only, or Trace and Memory. Press the Display soft key in
the Trace menu to open the Display menu. Then press the desired soft key to select trace or
trace memory, or both. To make distinguishing traces easier, the memory trace is assigned a
different color than the original trace. The corresponding memory trace number (shown in the
Instrument Settings Summary) uses a matching color. When viewing Memory Only, the
Instrument Settings Summary displays the information for M1. When viewing Trace and
Memory, the M1 information is displayed above the TR1 information.
At this point, the trace has been saved only to memory, and no trace math has been applied to
it. Click on the Trace Math soft key to apply one of the following functions: subtraction,
addition, multiplication, or division. The mathematical function operates on the complex
numbers for each of the traces. When dividing TR1 by M1, the result is the point-by-point
division of the complex numbers for each trace. Note that when trace math is applied to a
trace, the function is displayed in the instrument status window. In the above example,
assuming that S is the S-parameter that is associated with TR1, the status would display
11
TR1: S11/M1.
If a trace is saved to memory, and if some settings on the trace are then changed (such as
S-parameters, frequency, or number of points), then a mismatch occurs between the trace and
memory. The vector network analyzer allows you to change these trace settings, but it places
an asterisk next to the memory trace name in the instrument status window to point out the
mismatch. In the previous example, if a setting is changed on TR1 (relative to the memory
trace M1), then the listed filename is displayed as: M1: S11*. A similar mismatch occurs if
you save a measurement when trace math is applied (TR1: S11/M1, for example). When
that measurement is recalled, the result of the trace math is still stored in the memory
location. The trace math function, however, is no longer valid, and the memory trace contains
only the resulting S-parameter (S
in the memory location is based on previous measurements and calculations, the ^ sign is
placed next to the memory name: M1: S11^.
Vector Network Analyzer MG
in this example). To indicate that the data that are stored
11
PN: 10580-00289 Rev. K
2-4 Trace Math Capabilities
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