The signal output that can be obtained from ADALM-PLUTO was used with the IIO Oscilloscope to check its signal output level under several conditions.
First, I checked if the output level when running under the same conditions as the following Wiki page produced the same results.
The signal tone level is set to -12dB. But, when using digital loopback, the results on the Wiki page do not match the results in my setup for both "I/Q same signal" and "only I or only Q". Similarly, I tested other conditions, such as "One CW Tone" signal output and "RF loopback". The attached PPT slides shows all of these setups and output results. Please take a look. A table summarizing the results is included on the last page.
The attached table below is the same as the last page of the ppt slide.
Is it possible for you to tell me why the results are so varied for each condition, even though I have set -12dBFS as the signal level...? Is it ok to assume that this is the expected and correct output result we are seeing? It would be very helpful if you could advise me on how I should understand these results as they differ from the results on the Wiki page.
As background to my questions, I have a customer who is using ADALM-PLUTO with Raspberry Pi to check its operation, and we received some questions about its output level. In providing technical support for this customer, I first performed an operation check with ADALM-PLUTO + PC(IIO Oscilloscope) to have the customer confirm the expected signal output under simple conditions of Digital loopback and RF loopback with ADALM-PLUTO alone (stand-alone). Then, the output signal was varied like this for the -12dBFS signal setting, so I asked these questions.
To be honest, I am a beginner when it comes to RF signals, so it is possible that I do not understand some of these measurements and concepts. If this is something simple or not, it would be very helpful if you could explain from the basics to me.