Is this Agilent 33522A Function Generator damaged?

[dknguyen]

I was using an old Agilent 335522A function generator at work and noticed that it doesn't output what it says it outputs.

For example, the amplitude setting is in Vpp. But the actual amplitude is always double what is displayed (as if it was Vp). Furthermore, the offset that is output is always double what is displayed (as if it was intended to work with a Vpp amplitude).

For example, if I set the function generator to be sinewave that is:
Amplitude = 1Vpp
Offset = 500mV

Then what I actually get is a Sinewave that is 2Vpp and is offset enough just so it touches the zero line at the minimum valley.

Does anyone have any experience with this specific function generator? Can a function generator be damaged in such a way that causes this behaviour but otherwise seems to work fine?

EDIT: seems just googline this suggests that the function generator is working just fine is expecting a 50 ohm load and therefore compensating it's display as such, but I'm connecting it to high impedance loads?

 

[MikeMl]

I'm betting that the generator has a 50 source impedance, and expects a 50 Ohm load. If using a piece of RG58 coax cable to deliver the signal to a place several feet from the gen, you should terminate the coax in one of these.

Since that makes the VSWR on the cable low (both source end and load end terminated in 50 Ohms) the voltage reported by the instrument is correct...

 

[gophert]

Is this Agilent 33522A Function Generator damaged?

I've found most HP and Agilent instruments to be indestructible. Maybe it is the nut sitting in front of it.

 

[Les Jones]

I agree with Mike's theory.

Les.

 

[Nigel Goodwin]

I agree with Mike's theory.

Agreed, it's misuse not a fault.

 

[ronsimpson]

From the manual:
This phrase is all though the manual. "into a 50 ohm termination"

The output amplifier has a 50 ohm resistor from output to connector. (I have a drawer full of these ... they are a little hard to find)

The amplifier + resistor is designed to drive a 50 ohm coax, with out reflections and ring.