opensource imbe encoder

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gopher
Posts: 169
Joined: Fri Dec 22, 2006 11:38 am

opensource imbe encoder

Post by gopher »

gopher
Posts: 169
Joined: Fri Dec 22, 2006 11:38 am

Re: opensource imbe encoder

Post by gopher »

since this got tucked away in a dark corner...
if anyone is interested in this setup check out op25 http://sedition.org.au/op25/ work continues on this project, expect to see a repeater setup soon.
hard ware used is a usrp1 http://www.ettus.com/ which will set you back 700 big ones, plus rf boards...
my only tx board works in the 900mhz range but there was supposedly to be a 50mhz -1ghz transceiver, however it went vaporware...
the gnuradio toolkit is used for interfacing to the radio.
SDR is here to stay, it is the future of all radio communicatons
MattSR
Posts: 770
Joined: Mon Apr 21, 2003 10:00 pm

Re: opensource imbe encoder

Post by MattSR »

Im currently using OP25 with a TVRX. Need to get a RFX400 so I can test Max's repeater code.

I also emailed him and got him to check in the soundcard transmit code today too so I need to get that done ASAP is it will negate the need for a USRP :)
gopher
Posts: 169
Joined: Fri Dec 22, 2006 11:38 am

Re: opensource imbe encoder

Post by gopher »

cool let us know how it works.
i am surprised the range i got with just a 150mw signal. using a small diamond SRH805 HT Antenna mounted directly on the usrp on the 2nd floor of my house i was able to receive clear digital 300 feet down the stree in an urban neighborhood. not bad!
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Wowbagger
Aeroflex
Posts: 1287
Joined: Tue Dec 10, 2002 10:46 am

Re: opensource imbe encoder

Post by Wowbagger »

Are you sure the vocoder itself is open source? I watched the video, he said "P25 encoder" - which could refer to the vocoder, or to the rest of the framer/dibit coder/pulse shaping/modulation chain.

DVSI are VERY protective of their patents. Yes, you could, in theory, reverse engineer the IMBE vocoder from the patents + examination of the vocoded data stream, and create a piece of software that was GPL and implemented that algorithm. However, such a library would violate DVSI's patents, and would be absolute DEATH to use in any project where there was enough money to sue over.

Also, last I'd heard, everybody was using the DVSI USB dongles to do the vocoding - which means the vocoder isn't Free.

I'd like to hear more about this.
This is my opinion, not Aeroflex's.

I WILL NOT give you proprietary information. I make too much money to jeopardize my job.

I AM NOT the Service department: You want official info, manuals, service info, parts, calibration, etc., contact Aeroflex directly, please.
gopher
Posts: 169
Joined: Fri Dec 22, 2006 11:38 am

Re: opensource imbe encoder

Post by gopher »

all code used in the test program is open C++ including the imbe vocoder
MattSR
Posts: 770
Joined: Mon Apr 21, 2003 10:00 pm

Re: opensource imbe encoder

Post by MattSR »

gopher wrote:supposedly to be a 50mhz -1ghz transceiver, however it went vaporware...
Ettus released this as the WBX - and they extended the range to 50mhz-2.2Ghz.
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