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Cydrome Leader Cydrome Leader is offline
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Default tests to do on used oscilloscope?

Ralph Mowery wrote:
In article , says...

It seems that both frequency and voltage readings are off. I have an
old URM-25 RF signal generator that I have been feeding into it by
sampling off of the side of a t connector with one side having 50 ohm
dummy load and the other into ch 1 of the scope. Anything I've tried in
frequency and it seems like I'm reading at least double that frequency
on the scope if I count divisions from P-P. A 28 Mhz signal appears as
50 Mhz or plus on the scope. I just wonder if I'm overlooking something
here. Also, with the maximum output from the generator, 100,000 uV, I
am getting around 300,000 uV or more if I could divisions.




Your signal generator is probably set to give RMS voltage and you are
reading peak or peak to peak voltage on the scope. There is a
conversion factor of some number I can not recall but it is around 1.4
or 2.8 times. Also some generators will be open circuit voltage and
some into the 50 ohm load with is 6 db or someother number I can not
think of right off.


my signal generator outputs some wonky voltages unless you have a load
resistor across the outputs. It's 600ohms in a box with 1" spacing banana
plugs and receptacles. I could never figure out why that's not handled by
a pushbotton.

Also, make sure you don't have any knobs pulled out putting you in zoom
mode. My signal generator has one of silly scope knobs too for some
reason.