RF source for product testing/verification tool

[MatjazB]

Hello all,

I'm developing some products in ISM band (868 MHz). The part of the development is also testing the products (reception parameters, transmission parameters). Currently they are done using a classical spectrum analyzer (for Tx parameters). Reception parameters are done with our custom tools.

But I want to throw our custom tools out of the system.
Therefore I would need a RF generator.
Typically I'm measuring:

• reception bandwidth (changing frequency with fixed amplitude)
• sensitivity level (estimation)
• packet handling (transmitting different test packets)
• burst testing (transmitting large amount of data - multiple telegrams transmitted successively)

I have few hard requirements - it must be programmable (via USB/LAN), and amplitude must be stable.

I'm quite sure, that SDR is a way to go, but I'm worried about amplitude stability.
I can not find any (good?) information about SDR (Ettus USRP for example) amplitude stability.
I do not need extreme amplitude stability - for my cases it is enough that amplitude does not change for more than +/- 0.5 dBm. Actual amplitude value is not as much important to me, as stability over time.

How do SDRs preform? Any experience? Which device would you suggest?
Or do you think using a "real" RF generator (something from big players) is a better way to go?

Currently I'm looking at LimeSDR mini, and it seems to have everything I would like to have. But - I can not find any data about amplitude stability.

What do you think? What are your experiences?
 

[Ice-Tea]

Would a R&S CMU200 or CRTU-RU do?