Signal generator pulse shaping in the VNA mode

[naegele97]

Dear LibreVNA community,

I have a question regarding the signal generator in the VNA mode:
If I perform a frequency sweep then for each sweep point the signal generator runs a given time dt
for each frequency f during the sweep.
Is the amplitude of the signal
a) modulated during the time dt or
b) fixed at the set amplitude?
If b), then the signal pulse at frequency f with duration dt has a frequency bandwidth of 1/dt
which is quite large for fast sweep times. Is there an option for pulse modulation where the amplitude is
modulated in time such that the shape corresponds to, for example, a Hanning window?
I am looking forward to your answers!

[jankae]

It is option b. The LibreVNA hardware does not support pulse modulation, so there is not much I can do in the software to improve this (well, I could use the attenuator to achieve a very bad modulation while also reducing the adjustable output power range but I do not think that this is worth it).

The LibreVNA is primarily designed as a VNA and because of that the signal generator and spectrum analyzer modes have certain limitations. If you need better performance in either of these modes, my advice is always to get a dedicated device for it.

[naegele97]

Thank you for your reply. I just had the uneducated assumption that the implementation of the pulse modulation is easy to implement. Either way - the LibreVNA is still a great device for the price!