Oscilloscope vs MIM

[Mcking]

Moku model:
Moku:Pro
Operating system:
Microsoft Windows 10
Software version:
3.1.0

Bug or support request description:

With regards to our setup we are conducting some simple experiments and trying out different products and combinations you have to offer.

As of now our system setup looks like:

2 Output Channels → Our System (Sensing Device) → 2 Input Channels.
The 2 output channels are simpy generating Saw tooth signal with 180 degree out of phase
And the 2 input channels are reading the output after passing through our system.

Experiment 1 we conducted was basically just using an oscilloscope and seeing the outputs in the 2 channels. Please find attached the settings

Experiment 2 was conducted using multi-instrument setup but the same setup. The results don’t match up, and the result in peak to peak voltage is about 4 times lower. You can find the setup at the bottom.
https://drive.google.com/file/d/13cnHY1WYCYDpMnaxKYp4k7xiflzIeYJW/view?usp=drive_link
https://drive.google.com/file/d/1IHPp7-jOAMJBFnNUTnfCn-FzJlpj2zuQ/view?usp=drive_link

As far as I understand, the results should be the same given the signal sent to the system are same.

Can some shed some light on what am I missing, or where is it going wrong?

Cheers,
Naren

[nadia]

Hi @Mcking,

From looking at those figures it looks like the input signal in the Multi-Instrument set up is more like 10x less than the expected, this can be explained by the way Multi-Instrument mode attenuates the signal based on the range of the frontend. In Multi-Instrument mode, frontend settings such as attenuation are applied outside of the instrument, in this case, that means your signal will have been reduced 10x (-20dB) before it goes into the oscilloscope.

In the example below, Output 1 and Output 2 are the same signal, Input 1 is set to 400mVpp and Input 2 is set to 4Vpp, you can see that the signal is 10x smaller (-20dB) when looking at Channel B (Input 2), this needs to be accounted for in measurements with Multi-Instrument mode.