Interfered output at 2634B

[rododendron]

Hello,

I did some preliminary performance tests on our new 2634B and the output signals are sadly very interfered. I connected the HI output directly to the scope, with guard left unconnected. LO was bridged to GND. I've found there is a few hundred millivolt ripple, although the signal should be 0 V. The are periodically ringing signals (~130kHz freq.) and quite some noise.

Besides, when sourcing a voltage sweep and using a CC, there are very high voltage peaks induced to the signals - seems like coupled from the relays, which are switching to another current measurement range.

For our devices are ideally defined driving signals very important (influencing the kinetics), which makes this a crucial issue.

I'm wondering if you are aware of this performance, because I doubt this meet the specs of the SMU. Or could that be caused by the setup, incorrect wiring, ground loops or similar?

Please see the attached waveforms.

Thank you.
Regards,
Viktor

[Norbert W]

Hello,
if you have doubts about your instrument working correctly you can check its performance against its typcial noise specs.
One voltage noise spec is range dependent, e.g. 20 V range, 0.1 ... 10 Hz: 300 uV &c., which you could try to verify by
measurements with the instrument itself; the other one is a 'broadband' 10 Hz to 20 MHz spec for the 20 V range, which
takes a scope which allows a bandwidth reduction to 20 MHz and capable of related peak and rms measurements.