VNA concepts and features
R&S
®
ZNL/ZNLE
246
User Manual 1178.5966.02 ─ 19
●
Export time domain traces
●
Use export options.
Use the
Matlab (
*.dat
)
format if you want to import and process the trace data in
Matlab.
9.4.3
Memory-mapped trace data transfer
The VNA firmware uses the
Named Shared Memory
Windows feature to share trace
data with other processes running on the instrument. Such processes or applications
can read trace data directly from the shared memory, which is much faster than using
SCPI commands.
Multiple traces can be written to the same shared memory buffer. For each of these
traces, the firmware stores a configurable number of formatted or unformatted trace
values to a contiguous part of the shared memory.
●
A formatted (real) trace value takes up 8 bytes of memory.
●
An unformatted (complex) trace value takes up 16 bytes: 8 bytes for the real part, 8
bytes for the imaginary part.
Memory-mapped trace data transfer is a pure remote control feature. Once set up, the
VNA firmware refreshes the shared memory trace data with every sweep. Other pro-
cesses can read these data via standard APIs for Windows
Named Shared Memory
that are available for various programming languages.
You can create multiple shared memory buffers, e.g. with different intended life span.
Set up a shared memory buffer
The setup of a shared memory buffer and the allocation of trace data is performed by a
sequence of
INITialize
and
finished by a
COMMit
.
1. Initialize the shared memory buffer:
2. Add traces:
a)
'<TrName1>', FDATA|SDATa, #Values1
Select an existing trace name, choose whether to use formatted trace data
(
FDATa
) or unformatted trace data (
SDATa
), and define how many trace values
the firmware writes to the buffer per sweep.
The data block of the first trace has an offset of 0 bytes relative to the start of
the shared memory buffer.
Operations on traces
