This is a completely different problem, is it? Bandwidth is orthogonal to the concept of dynamic range and amplitude values.
Anyway, your FFT plot knows about complex samples; therefore, it displays dB relative to the numeric value of "1.0"; this has nothing to do with your input signal power. But since USRP/daughterboards tend to work linearly over most of their available power range, you can just add a multiply_const to your signal processing flowgraph and get your value. The factor, however, depends on your ADC/daughterboard combination, on the gain you set for the RF frontend, a little bit on temperature, the tuner, the impedance matching of your RF input to the Daughterboard etc. So if you already know what you're putting in, just use this as a reference and "calibrate" yourself. Hope that helped clear things up, Marcus On 10/04/2013 01:05 PM, Antmrt wrote:
Thanks Marcus, my problem is how to calibrate the scale on the FFT plot. e.g: I'm feeding a signal of -30 dBm to the usrp and on the plot the value becomes about -10 dBm -- View this message in context: http://gnuradio.4.n7.nabble.com/Changing-Bandwidth-USRP-tp43949p43952.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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