I am using the djx11 in I/Q mode with fcdp-tetra_demod.py.
I leave sample rate @ 96000 but low-pass filter (-L) 12.5Khz (gr firdes lp filter in complex
gives + - 12.5khz = bandwidth of 25khz).
this gives me excellent constellation and works fine on demod.
I hope this helps.
This patch just convert read/write into fread/write, which are buffered
and a bit faster... (actually, quite a lot faster) :-)
It works, have been tested at the CCC, and allow osmo-tetra to run in
real-time on a crappy Atom CPU.
Btw, if you like to run the entire decoding chain in real-time, just do
this (assuming that you use the funcube dongle):
./fcdp-tetra_demod.py -D hw:1,0 -c <offset> -o out.float
//(normally the fcdp runs on the second alsa port, change it to the
../../float-to-bits out.float out.bit
I'm still not 100% sure about the speech decoder, but i don't have any
good sniffer dump with speech traffic to test it, i will let you know in
a week or so...
Happy hacking! :-)
P.S. I have a plan to convert the float-to-bits code into a proper GNU
Radio module, shouldn't be too difficult, is there any interest into
continuing this project?
As I understood Harald is quite busy with other stuff (and rightfully
so), but I think that we should move forward. Volunteers? ;-)
After difficulty buying the funcubedongle i think i have found a
possible alternative piece of hardware.
Maybe even works better than FCD given a lot of people is reporting
that the dongle is sensitive to overloadis sensitive to overload.
It's a traditional radio-scanner receiver that provide a built in I/Q
output for use with SDR software.
Given I/Q connected to sound card, ¿would this work directly with fcdp-tetra_demod.py?
hello from France
Great job you did for Tetra decode .
I have a request concerning :
./src/float_to_bits /tmp/out.float /tmp/out.bits | ./src/tetra-rx
where can I find float_to_bits ?
where can I find tetra-rx ?
thanks for answer
http://www.fastmail.fm - Faster than the air-speed velocity of an
unladen european swallow
maybe somebody wants to reply...
Sent from a mobile device, excuse my short response
vahid jahandideh <vahid_jahandideh_1998(a)yahoo.com> wrote:
This is v.jahandideh a communication engineering student. I am studding TETRA protocol and i need your help.
i want to know how we can distinguish voice traffic for a specific subscriber,
can we do it by extracting the AACH and then looking to the header in AACH and associating a traffic usage marker whit each individual down link conversation. or there exist another solution for this problem. I would be appreciated if could make time to reply to my inquiry.