Redpitaya Forum

Posted: **Wed Jan 13, 2016 3:07 pm**

Hi All,

I am currently evaluating the RedPitaya for some testing purposes and use the SCPI interface to talk to it. First I put a saw tooth with the following settings on RF output 1:

Code: Select all

OUTPUT1:STATE ON
SOUR1:FREQ:FIX 2200
SOUR1:FUNC SAWD
SOUR1:VOLT 1
SOUR1:VOLT:OFFS 0
SOUR1:PHAS 0

I measured this sawtooth wave output with an Agilent DSO scope and found some not so nice ringing on the signal.

The overall signal looks as follows:

The same signal zoomed on the edge:

And once measured in parallel using a 10x scope probe:

Finally without 50 Ohm load it looks worse:

I really wonder what happens here. Comparing to the other GBFs I use (of course more expensive) the RF output of the RedPitaya seems not being as good as the specs say.

Any thoughts?

Thanks.
Cheers
Felix

Posted: **Wed Jan 13, 2016 7:12 pm**

You might want to try using this generate code:

viewtopic.php?f=7&t=526

Posted: **Fri Feb 17, 2017 8:15 pm**

Output impedance of generator is 50 ohms and it seems there is a mismatch between the impedance of the generator and the impedance of the load. Load the generator with an impedance of 50 ohms and the overshot will disappear or will be reduced.

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