Dimension of the y axis using usrp_oscope.py

GNU Radio
1

Hello!

I am doing some experiments using usrp_oscope.py. I am especially
interested in comparing the values obtained from the usrp devices and
those measured from a traditional oscope. Unfortunately one can’t find
any
hint which dimension (volts, etc.) is used for displaying the graph.

Thanks a lot for your help!

Cheers, Fabian

2

It will be completely dependent on your receiver chain. My understanding
is
that the values you are seeing are the output of the ADC, so you’ll need
to
figure out what the voltages at that point are. Perhaps someone else can
be
more helpful, but you’ll need to do the legwork.
What receiver are you using?
-William

3

Hello -

It will be completely dependent on your receiver chain. My understanding
is
that the values you are seeing are the output of the ADC, so you’ll need
to
figure out what the voltages at that point are. Perhaps someone else can
be
more helpful, but you’ll need to do the legwork.
What receiver are you using?
-William

I am using a LFRX board. I know that the usrp’s ADC has a resolution of
12bit, but what is the maximum value it can deal with? Unfortunately, I
haven’t found any information on this issue yet.

Looking forward to further pieces of advice.

Cheers, Fabian

4

You’ll need to read the datasheet for the ADC. It’s a AD9862. From
there
you’ll know the full range. I suspect is south of 3.3v as that’s the
boards
power supply.
An easier solution is to use a precision function generator and
calibrate.
Send in a known signal and see what the graph displays. Change the known
signal, rinse and repeat.
-William