Hi,

I am having problem with HP33120A function generator. The problem is the output amplitude. I set it to sine wave, 100mVpp, at 1kHz. I use 50 ohms coax cable and the oscilloscope to examine the output of the function generator. The oscilloscope display sine wave with amplitude 680mVpp at 1kHz. To be correct, the output should be less than 240mVpp sine wave at 1kHz. I try to set it to factory setting (100mVpp, sine wave at 1kHz) but it still give 680mVpp. Please help if anyone have encounter and solve this problem. Thanks in advance.

I am having problem with HP33120A function generator. The problem is the output amplitude. I set it to sine wave, 100mVpp, at 1kHz. I use 50 ohms coax cable and the oscilloscope to examine the output of the function generator. The oscilloscope display sine wave with amplitude 680mVpp at 1kHz. To be correct, the output should be less than 240mVpp sine wave at 1kHz. I try to set it to factory setting (100mVpp, sine wave at 1kHz) but it still give 680mVpp. Please help if anyone have encounter and solve this problem. Thanks in advance.

I setted to 50 ohms and also use a 50 ohms impedance coaxial cable. The result is still incorrect.

It sounds as though the oscillocope has a high input impedance (causing it to read twice the voltage of the 33120A when it is set for an output load of 50 Ohms) and then the oscilloscope is reading Vrms. (100 mVpp * 2) = 71 mVrms. If you are using a 10:1 probe setting on the oscilloscope, this will be displayed as 707 mVrms.

A few things to try:

I hope this helps!