Hi Folks,
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)
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 (attached) 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.
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..
I am using Ubuntu 12.04 64bit, Gnuradio 3.6.5.1, UHD 003.005, SSD disk, 8GB Ram, Intel
i7-3520M CPU.
Thanks..
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#!/bin/bash
sudo sysctl -w net.core.wmem_max=1048576
sudo sysctl -w net.core.rmem_max=50000000
rm /tmp/out.float /tmp/out.bits /tmp/out.codec /tmp/out.pcm /tmp/traffic.out
mkfifo /tmp/out.float
mkfifo /tmp/out.bits
mkfifo /tmp/out.codec
mkfifo /tmp/out.pcm
mkfifo /tmp/traffic.out
~/Desktop/osmo-tetra/src/demod/python/uhd-tetra_demod.py -f 394E6 -o /tmp/out.float &
float_to_bits /tmp/out.float /tmp/out.bits &
tetra-rx /tmp/out.bits &
cdecoder /tmp/traffic.out /tmp/out.codec &
sdecoder /tmp/out.codec /tmp/out.pcm &
aplay -fS16_LE /tmp/out.pcm
rm /tmp/out.float
rm /tmp/out.bits
rm /tmp/out.codec
rm /tmp/out.pcm
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Furkan Elibol
PhD Candidate
Ozyegin University
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