Rigol MSO5000 Bode Plot feature

[Sharp]

Hi guys

I hope one of you experienced guys can help me…    I’m looking into designing a low pass filer using my Rigol MSO5000 Bode Plot feature for the first time.

When I use LTSpice to simulate a LC filter I get a different result compared to my MSO5000.

BTW is it right that you only can use the Rigol probes in times 1 and not in times 10 setting ?

source 1V, coil: 0.010mH, 0.63 ohm and capacitor: 4,468 uF with ESR 6.2 ohm

[dustooff]

Hi,
can you post your LTspice file, or relevant section of it?

Initially I was thinking that the probes in x10 mode wouldn't allow the generator to match impedance correctly, but after that thought percolated for a bit, it didn't really make sense in relation as to how a FRA setup needs to be implemented.
The chapter 19 in the MSO5k user manual doesn't give much info about exactly how to connect the generator to the circuit under test, with the 'tips' picture showing a coupling transformer to impress the sweep signal on the test circuit. Just a suggestion of some type of pulse transformer, but I've also seen power amp modules for inclusion into bode measurement setups.
Some vids on FRA implementation by cleverscope give a reasonable overview.




This is a feature I'm trying to get more familiar with on my testbench.