AFG1022 voltage output problems?

[rontoolsie]

Hi, this is my first time on this forum.

I recently agreed to teach a physical electronics class to junior level physics students and am now evaluating the brand new signal generators and oscilloscopes we have gotten to ensure they are all fully functional. We have a roomful -maybe 14 or so of AFG1022 signal generators, with matching brand new 1152B-EDU oscilloscopes. The problem arises when I set the peak-to-peak voltages....the oscilloscope consistently gives me exactly DOUBLE the value I am expecting....i.e a 4V p2p produces an AMPLITUDE of 4V with 8V p2p. Yet the 1022 shows that the min/max values should be +/-2V, and not the +/- 4V I a, getting. The settings on the scope are x1 so there is no additional gain going on here (1x). When I take the waveforms out of a protoboard, using exactly the same scope settings I am getting the expected p2p voltages-so I know it is not a problem with the oscilloscope settings. Every value of p2p voltage I try has the same problem.

This inconsistency affects every one of the 14 signal generators. What am I missing?? I have my first lab to give in a week and if I do not get this resolved, I will have to rewrite the manual to eliminate the 1022 completely.

I have photographs of all of the output settings and oscilloscope displays, but I cannot apparently post them onto this forum.

Thanks in advance

Ron Toolsie MD

[Andrea C]

The amplitude specs of the AFG list conditions for loads of 50ohm and High-Z load.
When high-Z, the amplitude is double the 50ohm condition.
I suspect the input R of your scope (probe) is high-Z.

[rontoolsie]

Thank you for the very prompt and instructive reply. I will implement your suggestion and let you know if the issue has been resolved.