Multi-Instrument Mode Output Port Load Impedance

Moku model: Moku Pro
Operating system: Ipad/Apple
Software version: 2.5.1b12854

Dear Suport,

I realized that in the multi-instrument (MI) mode that I am not receiving as much RF power into the ESA as expected based upon the sinusoidal waveform with 1Vpp (1V^2/50ohm = 13 dBm of power).

I checked this in the single-module mode by just selecting the ESA module and there I noticed a difference in the menu for the output waveform: I was able to change the output impedance from the single module but not ESA in the MI mode.

In MI mode in the module overview I noticed for the input ports that I can change the input impedance to either 50ohm or 1Mohm, but I don’t see this option for the output ports. We are using 50ohm RF coax cable to connect these so is there a way to change the output load impedance on the ports in MI mode?

I am not sure what you mean by “ESA module” could you please clarify?

You are right that there is no option to change the output impedance because it is not switchable like the input impedance is. Moku:Pro’s output impedance is 50 ohms and the setting you are seeing in the standalone waveform generator is the expected load of the DUT. Changing between the expected 50 ohm DUT and 1 Mohm DUT switches between the 0 dB gain (1 Vpp mode) and +14 dB gain (10 Vpp mode) on the output.

In Multi-instrument Mode, we removed this option in the WG slot instrument because the output could be going to either another instrument slot (which has a max of 1 Vpp) OR to the Moku:Pro output (which you can set to be either 0 dB gain or +14 dB gain). I hope this clears up the confusion between the two different implementations and if you have any other questions please let me know!

Hi Sam,
I think here ESA is E series spectrum analyzer from Keysight probably.