1-19
Making Measurements
Using Display Functions
Using Memory Traces and Memory Math Functions
The analyzer has four available memory traces, one per channel. Memory traces are t otally
channel dependent: channel 1 cannot access the channel 2 memory trace or vice versa.
Memory traces can be saved with instrument states: one memory trace can be saved per
channel for each saved instrument state. There are up t o 3 1 s a ve/rec all registers available,
so the total number of memory traces that can be present is 128 including the four active
for the current instrument state. The memory data is stored as full precision, complex
data. Memory traces must be displayed in order to be saved with instrument states.
Additional data can be stored onto 3.5-inch floppy disks using the front panel disk drive.
NOTE You may not be able to store 31 instrument states if they include a large
amount of calibration data. The calibration data contributes considerably to
the size of the instrument state file and therefore the available memory may
be full prior to filling all 31 re gi sters.
Two trace math operations are implemented:
• (data/memory)
• (data−memory)
(Note that normalization is not .) Memory traces are saved and
recalled and trace math is done immediately after error-correction. This means that any
data processing done after error-correction, including parameter conversion, time domain
transformation (Option 010), scaling, etc., can be performed on the memory trace. You can
also use trace math as a simple means of error-correction, although that is not its main
purpose.
All data processing operations that occur after trace math, except smoothing and gating,
are identical for the data trace and the memory trace. If smoothing or gating is on when a
memory trace is saved, this state is maintained regardless of the data trace smoothing or
gating status. If a memory trace is saved with gating or smoothing on, these features can
be turned on or off in the memory-only display mode.
The actual memory for storing a memory trace is allocated only as needed. The memory
trace is cleared on instrument preset, power on, or instrument state recall.
If sweep mode or sweep range is different between the data and memory traces, trace math
is allowed, and no warning message is di spl ayed. If the number of points in the two traces
is different, the memory trace is not displayed nor rescaled. However, if the number of
points for the data trace is changed back to th e nu m be r o f po i nts in the memory, the
memory trace can then be displayed.
If trace math or display memory is requested and no memory trace exists, the message
CAUTION: NO VALID MEMORY TRACE is displayed.
To Save a Data Trace to the Display Memory
Press to store the current active measurement data in the
memory of the active channel. The data trace is now also the memory trace. You can use a
memory trace for subsequent math manipulations.
DATA/MEM
DATA-MEM
DATA/MEM
DATA-MEM
Display
DATA→MEMORY