Concepts and features
R&S
®
ZNA
295User Manual 1178.6462.02 ─ 20
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as input values for math functions for the calculation of other traces
To calculate a custom trace, the plug-in can make use of all data access points in the
channel calculation chain. See Chapter 4.1.6.1, "Channel data flow", on page 93).
Furthermore, it can communicate with other processes / peripherals that are not part of
the VNA firmware or host OS.
4.7.41.1 Basic use case
A basic use case is the integration of a power supply into an arbitrary VNA sweep.
Suppose that you want to test an amplifier with various bias settings. To do so, you can
perform a CW sweep to measure S-parameters with different gate voltages applied to
the amplifier at each sweep point.
With one power supply channel connected to the amplifier’s gate, and another channel
connected to the amplifier’s drain, the measurement could proceed as follows:
1. At the beginning of the sweep, the power supply is initialized (e.g. voltage setting
and current limit for each power supply channel) and then switched ON.
2. At the beginning of each sweep point, the plugin sets the power supply gate volt-
age to the next value.
3. At the end of each sweep point, the plugin reports the power supply reading of the
gate voltage and drain current to the VNA. These readings are displayed in dedica-
ted traces.
4. At the end of the sweep, the power supply is switched OFF.
4.7.41.2 Technology
The plug-in interface is a traditional C style DLL interface. Suitable DLLs can be com-
piled using different platforms, such as C or MATLAB. A plug-in is installed in the firm-
ware as a *.zip file, containing the external DLL and, possibly, additional files to be
kept with the DLL.
An SDK for external DLLs is provided with the analyzer firmware on the Rohde&
Schwarz internet pages.
For details, see the HTML help topics that are distributed with the plugin SDK.
Interactions of the external DLL with analyzer firmware and external devices are
synchronized with the measurement. Synchronization is done via callbacks from the
FW, at so-called interrupts. At an interrupt, the measurement takes a break and waits
for the FW to continue. During an interrupt, the plugin can access external devices and
return results to the FW.
Optional extensions and accessories
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