Hi All,
and thank you All for your Answers in my last thread.
Now i want to know, how i can convert the showing
values in the Y-Axis of the FFT-Plot Sink to dB, so that
i can interpret this correctly.
Do i have to define the max and min input value first ?
Results an input voltage 3.3V in the max Value(0dBFS)
i can watch in the FFT-Plot sink ?
Results an input voltage 0V in the min Value i can
watch in the FFT-Plot sink ?
As Stefan Brüns said in my last Thread:
"The reference point is 0dbFS - FS meaning Full Scale,
-32768…32767. The signal power you need to get this
readings from the ADC, or more exactly from the FPGA
depends on the daughterboard, PGA setting on the daughterboard,
decimation …
You have to calibrate your USRP to get from the sampling
values to input power in Watts."
So if i read for example the value +7.079 from my FFT-Plot
Sink, what does this mean ?
Is this higher than the reference(0dBFS) Point ?
I thouht the reference is the highest point.
How can i calibrate my USRP to get from the sampling values
to input power in dBW ?
I experimented with an example(See Attachment), but
this example use a virtual signal(software generated signal)
Amplitude of Signal: Value of FFT-Plot:
10e-3 -12.921
100e-3 7.079
1000e-3 27.079
So inreasing the Value with the multiply of 10 let the
y-Axis of the FFT-Plot increase by 20dB.
This behaves like dBW not dBV ?
Regards Markus