<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt"><div><span style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;">Hi Folks,</span><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><span style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;">I have a sample tetra signal without encryption. I generate a test signal from the tetra sample with a vector signal generator.(@394MHz carrier and 96KHz sampling rate)</span><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><span style="font-family: Helvetica; font-size: 16px; orphans: 2; text-align:
-webkit-auto; widows: 2;">I try to receive and listen this test signal realtime with USRP N200 and osmocom tetra. I combine all the osmocom tetra parts in one script (seen below) but speech is not continuous and aplay gives underrun warnings. The cpu usage is approximately %30 and there is no memory or disk write/read speed problem. I wonder what is the problem and how can i listen realtime tetra speech.</span><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><span style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;">I also test demodulator offline and then try the rest of the script realtime and there is no problem, i can listen continuous speech without any gap. So i suspect from the demodulator performance..</span><br style="font-family: Helvetica;
font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><span style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;">I am using Ubuntu 12.04 64bit, Gnuradio 3.6.5.1, UHD 003.005, SSD disk, 8GB Ram, Intel i7-3520M CPU.</span><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><br style="font-family: Helvetica; font-size: medium; orphans: 2; text-align: -webkit-auto; widows: 2;"><span style="font-family: Helvetica; font-size: 16px; orphans: 2; text-align: -webkit-auto; widows: 2;">Thanks..</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span style="font-family: Helvetica; font-size: 16px;
orphans: 2; text-align: -webkit-auto; widows: 2;"><span style="font-size: medium; text-align: -webkit-auto;">------------------------------------------------------------------</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">#!/bin/bash</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">sudo sysctl -w net.core.wmem_max=1048576</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">sudo sysctl -w net.core.rmem_max=50000000</span><br style="font-size: medium; text-align: -webkit-auto;"><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">rm /tmp/out.float /tmp/out.bits /tmp/out.codec /tmp/out.pcm /tmp/traffic.out</span><br style="font-size: medium; text-align: -webkit-auto;"><br
style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">mkfifo /tmp/out.float</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">mkfifo /tmp/out.bits</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">mkfifo /tmp/out.codec</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">mkfifo /tmp/out.pcm</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">mkfifo /tmp/traffic.out</span><br style="font-size: medium; text-align: -webkit-auto;"><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">~/Desktop/osmo-tetra/src/demod/python/uhd-tetra_demod.py -f 394E6 -o
/tmp/out.float &</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">float_to_bits /tmp/out.float /tmp/out.bits & </span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">tetra-rx /tmp/out.bits &</span><br style="font-size: medium; text-align: -webkit-auto;"><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">cdecoder /tmp/traffic.out /tmp/out.codec &</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">sdecoder /tmp/out.codec /tmp/out.pcm &</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">aplay -fS16_LE /tmp/out.pcm</span><br style="font-size: medium; text-align: -webkit-auto;"><br
style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">rm /tmp/out.float</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">rm /tmp/out.bits</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">rm /tmp/out.codec</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">rm /tmp/out.pcm</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">------------------------------------------------------------------</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium; text-align: -webkit-auto;">Furkan Elibol</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: medium;
text-align: -webkit-auto;">PhD Candidate</span><br style="font-size: medium; text-align: -webkit-auto;"><span style="font-size: 16px; text-align: -webkit-auto;">Ozyegin University</span><br></span></div></div></body></html>