On Fri, Mar 12, 2010 at 11:17:13AM +0100, Sergio Benco wrote: > > I'm interested in extracting samples from USRP to perform some spectrum > analysis on them. I use an USRP and a XCVR2450 to receive signals in the > ISM 2.4GHz band. My setup in GRC is a USRP (decim 64, gain 0dB, baseband > 2.405GHz) connected to a file sink. This file is then processed by > read_complex_binary.m located in the directory .../gnuradio-core/utils/. > Its output, for a sampling rate of 1MS/s, gives (I printed out only a > small part): > > -18 - 19i > -22 - 12i > -2 - 8i > -23 - 31i > 21 + 62i > -62 - 231i > 76 + 510i > -128 - 1023i > 240 + 1925i > -571 - 3749i > 3643 + 10423i > 14675 - 14352i > 21379 + 3772i > -1807 + 4089i > 851 - 2080i > -483 + 1112i > 251 - 553i > -135 + 256i > 54 - 96i > -24 + 13i > -3 - 12i > -8 - 1i > -8 - 1i > > Now I would to know how the 12 bit samples from ADC are mapped in 16 bit > signed integers. Since now I know that the samples (12 bit, 4096 levels) > come into the USB after a mapping to USB's 16 bit signed integers with 4 > bits zeroed. I would understand better the process of sampling in the > USRP from the analog signal, to 12 bit samples (signed? so 2^11 levels = > 2048), to 16 bit signed integers (2^15 = 32768) as seems to be appened > from my printout. How could I correlate the signal on antenna with these > 16 bit samples? > > BR, > Sergio Benco
Please read the USRP FAQ. Eric _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
