Maillist wrote: >>> Joacim wrote: >>>> I executed dvbsnoop (with -s singal) during a scan and when finding channels >>>> I >>>> got: >>>> Sig: ~46000 >>>> SNR: 0 (?????) >>>> BER: 0 >>>> >>>> Can I trust the values from dvbsnoop?? Any better tool?? >>> I use femon from the dvb-tools package (or the VDR-plugin named the same). >>> >>> /Richard >> I tested 'tzap' and 'femon' >> >> root@frodo:/home/joacim# tzap -a 0 "Nickelodeon" >> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0' >> tuning to 594000000 Hz >> video pid 0x03bf, audio pid 0x03be >> status 0b | signal 8fff | snr 0000 | ber 001fffff | unc 00003c4c | >> status 1f | signal 9036 | snr 0000 | ber 00000000 | unc 00002347 | FE_HAS_LOCK >> status 1f | signal 9040 | snr 0000 | ber 00000000 | unc 00003e98 | FE_HAS_LOCK >> status 1f | signal 902e | snr 0000 | ber 00000000 | unc 00003c57 | FE_HAS_LOCK >> status 1f | signal 9014 | snr 0000 | ber 00000000 | unc 00003efe | FE_HAS_LOCK >> >> root@frodo:/home/joacim# femon -a 0 >> using '/dev/dvb/adapter0/frontend0' >> FE: DiBcom 3000MC/P (TERRESTRIAL) >> status 1f | signal 8e6e | snr 0000 | ber 00000000 | unc 00003ef9 | FE_HAS_LOCK >> status 1f | signal 8e6e | snr 0000 | ber 00000000 | unc 00003ef9 | FE_HAS_LOCK >> status 1f | signal 8e6e | snr 0000 | ber 00000000 | unc 00003ef9 | FE_HAS_LOCK >> status 1f | signal 8e6e | snr 0000 | ber 00000000 | unc 00003ef9 | FE_HAS_LOCK >> status 1f | signal 8e6e | snr 0000 | ber 00000000 | unc 00003ef9 | FE_HAS_LOCK >> >> >> I get SNR 00000 with both apps, singal varies a bit between them. >> Is it possible to get SNR info out of Nova-T or could it that bad ??? >> >> -- >> Regards >> Joacim >> > > One other question (since I don't have total grip of this area). > I have also 2 Dreamboxes and those are showing: > SNR: 99% > AGC: 60% > BER: 0 > > SNR, I understand quite well I think. Higher values means better quality and > less noise. I should not only focus on high values but also a stable value. > > AGC, I don't understand. Can someone explain this?? > > BER, I think I understand this, Bit Error Rate means errors in the signal that > could not be interpreted by the receiver. Should be as low as possible. > > Please correct me and/or fill in to increase my knowledge :) > > Regards > Joacim > > In a nutshell, AGC (Automatic Gain Control) attempts to present a constant signal output, it's a compensation loop. If the received signal rises beyond a certain level, AGC acts to attenuate it, if the signal decreases, e.g due to fading AGC acts to amplify the signal. Constant voice/video output for a large variation in received signals. Regards Sid. -- Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support Specialist, Cricket Coach Microsoft Windows Free Zone - Linux used for all Computing Tasks _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
