FAQs from Rohde & Schwarz

Changing the update display rate of a sweep with many sweep points.

Question

I need to measure a plasma and I need a sweep with 40 000 sweep points.

The displayed sweep time from the VNA is 1.44 sec. This would be OK, but when I look at the effective sweep time (Pin 4 of the User Control connector), it is around 3 sec.

Changing the update display rate of a sweep with many sweep points.

Why is this, and how can I change it?

Answer

With the standard settings, the VNA measures some points, then it updates a part of the display, measures some more points, updates a part of the display and so on until the whole sweep is done.

With the following command you can change this:

:SYSTem:DATA:SIZE ALL

With this command, the VNA measures all sweep points and updates the display afterwards in one go.

Now the effective sweep time is much faster:

Changing the update display rate of a sweep with many sweep points.