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Bhaskar11 niceguy108 at gmail.comI checked the SNR value from: sp->bursts[bidx].snr This is quite different from: dsp_api.db_r->a_serv_demod[D_SNR] The dump of the two values is below: freq_err=97, snr=216. bsnr=104. freq_err=-7, snr=183. bsnr=247. freq_err=19, snr=405. bsnr=16384. freq_err=-10, snr=189. bsnr=16384. freq_err=-163, snr=318. bsnr=16384. freq_err=-27, snr=470. bsnr=16384. freq_err=-23, snr=483. bsnr=16384. freq_err=99, snr=660. bsnr=16384. freq_err=-64, snr=1752. bsnr=16384. SACCH freq_err=-10, snr=476. bsnr=16384. freq_err=-206, snr=476. bsnr=16384. freq_err=-34, snr=326. bsnr=123. freq_err=-256, snr=217. bsnr=250. freq_err=-81, snr=181. bsnr=16384. freq_err=-190, snr=245. bsnr=16384. freq_err=-98, snr=113. bsnr=16384. What is causing the difference in TCH? B. On Wed, Mar 20, 2013 at 9:07 PM, Bhaskar11 <niceguy108 at gmail.com> wrote: > Dear Sylvain, > > I'm studying traffic data using ccch_scan in burstind branch. > > In prim_sniff.c I track the SNR levels in l1s_sniff_resp() using code from > print_tch.c to read snr values from: dsp_api.db_r->a_serv_demod[D_SNR]; > > I find that the level changes sharply from ccch mode to tch mode. > > In ccch mode most of the snr values are 16384. After switching to tch mode > they range from 200 to 600 typically! > > Is this normal? Am I doing something wrong when changing mode? > > Below is the dump of snr values and freq_err during the run. > > B. > > =============== data dump > fnx = fn % 26; > freq_err = ANGLE_TO_FREQ(dsp_api.db_r->a_serv_demod[D_ANGLE]); > snr = dsp_api.db_r->a_serv_demod[D_SNR]; > > > fnx=6, bidx=0, freq_err=-24, snr=16384. SACCH > fnx=7, bidx=0, freq_err=-6, snr=16384. SACCH > fnx=8, bidx=0, freq_err=9, snr=16384. SACCH > fnx=9, bidx=0, freq_err=-15, snr=16384. SACCH > fnx=25, bidx=0, freq_err=-26, snr=16384. > fnx=0, bidx=0, freq_err=10, snr=16384. > fnx=1, bidx=0, freq_err=38, snr=16384. > fnx=2, bidx=0, freq_err=-14, snr=*16384*. > fnx=24, bidx=0, freq_err=46, snr=*16384*. > fnx=25, bidx=0, freq_err=23, snr=*16384*. > fnx=0, bidx=0, freq_err=-1, snr=*16384*. > afc_correct(error=-1Hz, arfcn=24): delta=0, afc_dac(old=544,new=544) > fnx=1, bidx=0, freq_err=22, snr=16384. > *(Immediate Assignment starts here)* > L1CTL_FBSB_REQ (arfcn=4, flags=0x7) > Starting FCCH RecognitionFB0 (1266881:8): TOA= 8784, Power= -61dBm, > Angle=10831Hz > afc_correct(error=10831Hz, arfcn=4): delta=1283, afc_dac(old=-700,new=583) > FB0 (1266892:9): TOA=10032, Power= -61dBm, Angle= -340Hz > afc_correct(error=-340Hz, arfcn=4): delta=-40, afc_dac(old=583,new=543) > FB1 (1266902:8): TOA= 8755, Power= -61dBm, Angle= 0Hz > afc_correct(error=0Hz, arfcn=4): delta=0, afc_dac(old=543,new=543) > fn_offset=1266900 (fn=1266902 + attempt=8 + ntdma = 6) > delay=8 (fn_offset=1266900 + 11 - fn=1266902 - 1 > scheduling next FB/SB detection task with delay 8 > =>FB @ FNR 1266900 fn_offset=1266900 qbits=4836 > Synchronize_TDMA > LOST 3717! > SB1 (2533807:1): TOA= 26, Power= -61dBm, Angle= 176Hz > => SB 0x00a9dd65: BSIC=25 fn=1266912(955/10/21)=> DSP reports SB in bit > that is 1127709799 bits in the future?!? > Synchronize_TDMA > => DSP reports FB in bit that is 1127709776 bits in the future?!? > LOST 1907! > afc_correct(error=4Hz, arfcn=4): delta=0, afc_dac(old=543,new=543) > L1CTL_DM_EST_REQ (arfcn=12545, chan_nr=0x15, tsc=1) > LOST 3047! > *(tch mode is now active)* > fnx=4, bidx=0, freq_err=-92, snr=*238*. > fnx=6, bidx=0, freq_err=-132, snr=*82*. > fnx=8, bidx=0, freq_err=103, snr=*145*. > fnx=10, bidx=0, freq_err=-234, snr=*316*. > fnx=12, bidx=0, freq_err=-89, snr=*292*. SACCH > fnx=13, bidx=0, freq_err=46, snr=*270*. > fnx=15, bidx=0, freq_err=35, snr=*387*. > fnx=17, bidx=0, freq_err=201, snr=*1055*. > fnx=19, bidx=0, freq_err=130, snr=549. > fnx=21, bidx=0, freq_err=-94, snr=51. > fnx=23, bidx=0, freq_err=-52, snr=173. > fnx=0, bidx=0, freq_err=157, snr=322. > fnx=2, bidx=0, freq_err=107, snr=95. > afc_correct(error=12Hz, arfcn=24): delta=1, afc_dac(old=543,new=544) > fnx=4, bidx=0, freq_err=86, snr=135. > fnx=6, bidx=0, freq_err=-126, snr=207. > > ==================================== > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/baseband-devel/attachments/20130320/2be468c6/attachment.htm>