Digital Speech Decoder and mbelib
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Northerner71
Member
Let me get this straight.
This program will do what? I am sort of new at this tech. If I understand correctly this software will allow me to hook up any dis. tapped scanner, run it through this software and it will descramble digital voice with the exception of encrypted talk? Man that would be nice. Any feed back would be nice.
This program will do what? I am sort of new at this tech. If I understand correctly this software will allow me to hook up any dis. tapped scanner, run it through this software and it will descramble digital voice with the exception of encrypted talk? Man that would be nice. Any feed back would be nice.
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- Jan 7, 2006
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Go to Page 1 and start again, it's explained in detail in the first post.
If you want P25 audio then generally the answer is yes. A digital scanner might sound better but DSD works wonderfully and provides additional info not currently displayed by any digital scanner.
Given the similarities between MacOS (BSD) and Linux, has anyone given this a try on a Mac yet?
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AZScanner
Member
Is the mac running Linux? That'd be the only way this code would work as is.
Glad to hear an XP port is in the works. Linux is cool but I'm much more comfortable in XP. Looking forward to it, thanks DSD team!
-AZ
It was pointed out via PM that dsd was displaying incorrect nac id's. That will be fixed in the next release. Also, all of the p25 metadata (lcformat, mfid, lcinfo, keyid, algid, mi, lsd) was being printed in reverse bit order. That will also be fixed in the next release.
It looks like the easiest way to port dsd to mac and windows is with the portaudio library. I will see if I can get support for that into the next release.
It looks like the easiest way to port dsd to mac and windows is with the portaudio library. I will see if I can get support for that into the next release.
Note that with NFM, group delay error doesn't directly show up in the demodulated signal (as would be the case with AM or sideband, which linearly translates the band). Group delay error can't be good of course, but how to pin down it's effects predictably seems tricky to me with NFM.
A saw filter would be linear phase, but 455khz is a bit low for a saw filter. A quick google search only digs up ceramics. It would be possible these days (given op amp technology) to do an active 455kHz filter and linearize the phase in the passband.
Personally, I'd like to see this program incorporate trunker and keep everything under linux. This was the easiest linux installation I ever did. No .config, and no dependency issues. Further, if you go on sourceforge, the program is posix, so in theory it would be possible to use a linux binary provided you have your linux box set up for posix.
I have it running under opensuse 11.2. With the -u5 option, it does burst of 25% on one of my CPUs. [AMD quad phenom.]
I've got acarsd and hdfl (under wine) running on the linux box, and find multiple soundcard project much simpler under linux. The KDE kmix easily sets up each card. I have enough PCI slots for 8 cards at the moment using a Magma PCI expander chasis. [Totally plug and play under linux.]
I'm running Diamond XS71 cards which have the 8 bit mode should the author wish to support it. [Acarsd requires 8 bit mode.] These cards install under alsa as CMI8768 (i.e. the C-Media chip). The cards are quite cheap, about $20 on sale or with rebate.
I have it running under opensuse 11.2. With the -u5 option, it does burst of 25% on one of my CPUs. [AMD quad phenom.]
I've got acarsd and hdfl (under wine) running on the linux box, and find multiple soundcard project much simpler under linux. The KDE kmix easily sets up each card. I have enough PCI slots for 8 cards at the moment using a Magma PCI expander chasis. [Totally plug and play under linux.]
I'm running Diamond XS71 cards which have the 8 bit mode should the author wish to support it. [Acarsd requires 8 bit mode.] These cards install under alsa as CMI8768 (i.e. the C-Media chip). The cards are quite cheap, about $20 on sale or with rebate.
I'd encourage you (or the author since) just to work on linux. Once it is mature, it can be ported to other platforms. Thus far this is the easiest linux program I ever installed (compiled), so I am sure anyone who makes the effort can get it running under linux. I'd really like to see this combined with trunker. Assuming the use of full duplex soundcards, it seems one channel could listen to the CC, the other the demd (obviously from a different radio), and also output the decoded sound.
PCs used for decoding really should be on dedicated hardware. It doesn't have to be cutting edge. Anyway, once you dedicate the hardware, running linux is no longer a disadvantage but rather an advantage since you don't need to buy the OS. The dedicated PC I use for decoding uses that cheesy on-mobo video, just fine for this kind of work.
It's been my experience that most linux programs ported to the PC run so much poorer than on the native box, especially firefox.
I haven't tried the software yet but if there's any CAI data that needs to be verified I can do that with my P25 service monitor.
I have used active radios on a P25 system to verify the operation of DSD. Aside from some minor hickups it is an exellent program. I am looking forward to later releases which I hope will give a more indepth analisis of P25 signals.
It would be interesting if your service monitor could recreate console commands such as radio inhibit, live mic and some PDU based commands.
woodpecker
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Does anyone have some high quality P25 wav files that could be used to try DSD, there is no P25 here but I would like to try the software. TIA.
slicerwizard
Member
I have a 14 MB file; if you have a Gmail address, I can send it directly to you.
It does indeed support this already (and has for a while). The intent was to support (a) any computer controlled radio with an after market P25 conversion module (like the ARD-25) or (b) this mechanism. You would have to pipe the discriminator audio of the voice radio to a Linux box running this utility.
On the Receiver panel look for the P25, ProVoice and VSELP check boxes under the "Control" section like so ...
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