On Mon, Jun 21, 2010 at 5:31 AM, Sven Oliver Kreis <svenoliverkr...@googlemail.com> wrote: > Hi there, > > I am using an USRP2 with Gnu Radio Companion 3.3 and XCVR2450 as > daughterboard. I created a simple signal generator with grc. > > Signal Source (Sample Rate 12.5M, Waveform: Sine, Frequency: 1, > Amplitude also 1, Offset 0) connected to USRP2 Sink (Interpolation 128, > Frequency: 2,481GHz) >
1.0 is the maximum amplitude. sounds like your clipping and saturating. try bumping that down by half or so before taking measurements -Josh > I am also using one micaz node for RSSI Measurement. (using RssiToSerial > and a serial programming board) Distance between SDR and micaZ about > 0.5m. > > Taking 10000 RSSI Values per dB Step (stopping, changing Gain +1 in > USRP2 Sink, starting again with GRC ) I got the attached result. > (attached max RSSI value, can also attach average value, which looks > similar if requested) > > I started at 0 dB Gain, so x= 1 <=> 0 dB GAIN at USRP2 Sink. > > Noise floor is at -97 dBm (not in the plot). Starting USRP2 with Gain 0 > gets it to about -62/-63 dBm at 0.5m distance. > Increasing gain increases RSSI value as expected. Not quite linear but I > expected that. > > At a gain of 20 the RSSI value reaches about -46 dbM. Increasing USRP2 > Sink gain over 20 doesn't change anything. It seems to stay at about > -46/-45 dBm. > > Printing gain range results in 0 to 30 dB. Also mingain = 0 and maxgain > = 30. > > How to get more tx_gain? Something I do wrong there to make gain > 20 > take effect? > > I can also attach the python code, if requested. > > Thx in advance > Sven Oliver > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
