SDRTrunk - p25 decoder test release

[mtindor]

Originally Posted by DSheirer

I posted the first test build of SDRTrunk with integrated P25 audio decoding to the downloads folder:

https://code.google.com/p/sdrtrunk/

You'll need to download and compile the JMBE library and place the library in the same folder where you unzip your sdrtrunk application. There is an updated description of the APCO25 decoder and how to use the JMBE library at:

https://code.google.com/p/sdrtrunk/wiki/APCO25

If you've previously downloaded and compiled the jmbe library, you'll need to update and build version 0.1.1.

If you have any issues or need any help, please PM me, post a reply here, or post a new message in the sdrtrunk yahoo group.

Denny

Hi Denny,

I'm not seeing jmbe-0.1.1. When I download from your link and compile, it creates the jar file for jmbe-0.1.0, and the Changelog in the code says its 0.1.0 initial

I'm sorry for the silly question, but how do I get the 0.1.1 version?

Mike

[DSheirer]

Originally Posted by mtindor

Hi Denny,

I'm not seeing jmbe-0.1.1. When I download from your link and compile, it creates the jar file for jmbe-0.1.0, and the Changelog in the code says its 0.1.0 initial

I'm sorry for the silly question, but how do I get the 0.1.1 version?

Mike

Sorry about that. Try updating again.

I'm transitioning from svn to git and apparently have a few more things to learn :-)

Denny

[mtindor]

Originally Posted by DSheirer

Sorry about that. Try updating again.

I'm transitioning from svn to git and apparently have a few more things to learn :-)

Denny

Thank you, Denny. Everything compiled without a hitch. Great job on making this extremely easy to do [once the Ant environment is in place].

Now, for me to test it out -- I have to wait til later to test. I'll be testing it on a P25 LSM system.

Mike

[mtindor]

Denny,

I compiled the latest SDRTrunk and latest JMBE. i installed it on my Windows 7 machine. I'm running two RTL tuners.

The JMBE Jar is in the same directory as the sdrtrunk.jar and the run scripts. But I'm not seeing any indication that the JMBE is being detected and supported in the startup logs.

C:\sdrtrunk>run_sdrtrunk_windows.bat

C:\sdrtrunk>java -cp "SDRTrunk.jar;libs/*;config/*;images/*" gui.SDRTrunk
13:27:48.617 INFO  gui.SDRTrunk -
13:27:48.620 INFO  gui.SDRTrunk -
13:27:48.622 INFO  gui.SDRTrunk - *******************************************************************
13:27:48.625 INFO  gui.SDRTrunk - **** SDRTrunk: a trunked radio and digital decoding application ***
13:27:48.625 INFO  gui.SDRTrunk - ****  website: https://code.google.com/p/sdrtrunk               ***
13:27:48.627 INFO  gui.SDRTrunk - *******************************************************************
13:27:48.630 INFO  gui.SDRTrunk -
13:27:48.632 INFO  gui.SDRTrunk -
13:27:48.640 INFO  gui.SDRTrunk - Home path: C:\Users\mtindor\SDRTrunk
13:27:48.642 INFO  p.SystemProperties - SystemProperties - loaded [C:\Users\mtindor\SDRTrunk\SDRTrunk.properties]
13:27:48.642 INFO  p.SystemProperties - SystemProperties - application properties loaded [C:\Users\mtindor\SDRTrunk\SDRT
runk.properties]
13:27:48.650 INFO  settings.SettingsManager - SettingsManager - loading settings file [C:\Users\mtindor\SDRTrunk\setting
s\settings.xml]
13:27:48.795 INFO  playlist.PlaylistManager - PlaylistManager - loading playlist file [C:\Users\mtindor\SDRTrunk\playlis
t\playlist.xml]
13:27:48.900 INFO  s.r.RecordingSourceManager - RecordingSourceManager - discovered [0] recording configurations
13:27:48.987 INFO  source.mixer.MixerManager - loading system mixer devices
        [NOT LOADED] Mixer:Primary Sound Driver - audio format not supported
        [NOT LOADED] Mixer:Speakers / Headphones (IDT High Definition Audio CODEC) - audio format not supported
        [NOT LOADED] Mixer:Line 3 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Line 4 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Line 1 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Line 2 (Virtual Audio Cable) - audio format not supported
        [LOADED]     Mixer:Primary Sound Capture Driver CHANNELS: [LEFT, RIGHT, MONO]
        [LOADED]     Mixer:Line 4 (Virtual Audio Cable) CHANNELS: [LEFT, RIGHT, MONO]
        [LOADED]     Mixer:Line 3 (Virtual Audio Cable) CHANNELS: [LEFT, RIGHT, MONO]
        [LOADED]     Mixer:Line 2 (Virtual Audio Cable) CHANNELS: [LEFT, RIGHT, MONO]
        [LOADED]     Mixer:Line 1 (Virtual Audio Cable) CHANNELS: [LEFT, RIGHT, MONO]
        [LOADED]     Mixer:Rec. Playback (IDT High Definit CHANNELS: [LEFT, RIGHT, MONO]
        [NOT LOADED] Mixer:Port Speakers / Headphones (IDT High - audio format not supported
        [NOT LOADED] Mixer:Port Line 3 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Line 4 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Line 1 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Line 2 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Line 3 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Line 2 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Line 4 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Line 1 (Virtual Audio Cable) - audio format not supported
        [NOT LOADED] Mixer:Port Rec. Playback (IDT High Definit - audio format not supported

13:27:49.332 INFO  source.tuner.TunerManager - LibUSB API Version: 16777474
13:27:49.335 INFO  source.tuner.TunerManager - LibUSB Version: 1.0.18.10866
13:27:49.972 INFO  source.tuner.TunerManager - discovered [11] attached USB devices
13:27:49.985 INFO  source.tuner.TunerManager - usb device [8086:1E2D] NOT LOADED: Unknown Device
13:27:49.987 INFO  source.tuner.TunerManager - usb device [8086:1E26] NOT LOADED: Unknown Device
13:27:50.272 DEBUG source.tuner.TunerManager - attempting to construct R820T tuner controller
13:27:50.285 DEBUG source.tuner.TunerManager - initializing R820T tuner controller
13:27:50.952 DEBUG s.t.r.r.R820TTunerController - initializing RTL2832 tuner baseband
13:27:51.200 DEBUG s.t.r.r.R820TTunerController - enabling I2C repeater
13:27:51.205 DEBUG s.t.r.r.R820TTunerController - initializing R820T tuner
13:27:51.510 DEBUG s.t.r.r.R820TTunerController - disabling I2C repeater
13:27:51.515 DEBUG s.t.r.r.R820TTunerController - initializing RTL2832 tuner controller super class
13:27:51.595 DEBUG source.tuner.TunerManager - applying tuner config to R820T tuner
13:27:51.797 INFO  source.tuner.TunerManager - usb device [0BDA:2838] LOADED: RTL2832 SDR/R820T #00000100
13:27:52.070 DEBUG source.tuner.TunerManager - attempting to construct R820T tuner controller
13:27:52.070 DEBUG source.tuner.TunerManager - initializing R820T tuner controller
13:27:52.737 DEBUG s.t.r.r.R820TTunerController - initializing RTL2832 tuner baseband
13:27:52.982 DEBUG s.t.r.r.R820TTunerController - enabling I2C repeater
13:27:52.990 DEBUG s.t.r.r.R820TTunerController - initializing R820T tuner
13:27:53.290 DEBUG s.t.r.r.R820TTunerController - disabling I2C repeater
13:27:53.297 DEBUG s.t.r.r.R820TTunerController - initializing RTL2832 tuner controller super class
13:27:53.355 DEBUG source.tuner.TunerManager - applying tuner config to R820T tuner
13:27:53.555 INFO  source.tuner.TunerManager - usb device [0BDA:2838] LOADED: RTL2832 SDR/R820T #00000101
13:27:53.557 INFO  source.tuner.TunerManager - usb device [0C45:644B] NOT LOADED: Unknown Device
13:27:53.557 INFO  source.tuner.TunerManager - usb device [1A40:0201] NOT LOADED: Unknown Device
13:27:53.560 INFO  source.tuner.TunerManager - usb device [3938:1047] NOT LOADED: Unknown Device
13:27:53.562 INFO  source.tuner.TunerManager - usb device [8087:0024] NOT LOADED: Unknown Device
13:27:53.565 INFO  source.tuner.TunerManager - usb device [8087:0024] NOT LOADED: Unknown Device
13:27:53.567 INFO  source.tuner.TunerManager - usb device [8087:07DA] NOT LOADED: Unknown Device
13:27:53.570 INFO  source.tuner.TunerManager - usb device [8086:1E31] NOT LOADED: Unknown Device
13:27:53.580 INFO  gui.SDRTrunk - Available Audio Converter: class com.sun.media.sound.AudioFloatFormatConverter
13:27:53.582 INFO  gui.SDRTrunk - Available Audio Converter: class com.sun.media.sound.UlawCodec
13:27:53.585 INFO  gui.SDRTrunk - Available Audio Converter: class com.sun.media.sound.AlawCodec
13:27:53.585 INFO  gui.SDRTrunk - Available Audio Converter: class com.sun.media.sound.PCMtoPCMCodec
13:27:53.940 ERROR o.j.swingx.JXMapViewer - JXMapViewer could not load 'loading.png'
13:27:54.077 DEBUG s.t.r.RTL2832TunerController - rtl2832 [00000100] - starting sample fetch thread
13:27:54.130 DEBUG d.p.a.IMBETargetDataLine - Constructing instance of TDL
13:27:54.132 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_binary_messages.log
13:27:54.135 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_decoded_messages.log
13:27:54.135 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_call_events.log
13:27:54.145 INFO  gui.SDRTrunk - Channel [OC Simu VC] - - started audio recording [C:\Users\mtindor\SDRTrunk\recordings
\20150404_132754_OC Simu VC_audio.wav]
13:27:54.180 ERROR s.tuner.rtl.RTL2832Tuner - couldn't provide source channel
org.usb4java.LibUsbException: USB error 9: error writing byte buffer: Pipe error
        at source.tuner.rtl.RTL2832TunerController.write(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.rtl.RTL2832TunerController.write(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.rtl.RTL2832TunerController.writeI2CRegister(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.rtl.r820t.R820TTunerController.writeR820TRegister(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.rtl.r820t.R820TTunerController.setMux(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.rtl.r820t.R820TTunerController.setTunedFrequency(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.FrequencyController.setFrequency(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.FrequencyController.setFrequency(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.TunerController.updateLOFrequency(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.TunerController.getChannel(Unknown Source) ~[SDRTrunk.jar:na]
        at source.tuner.rtl.RTL2832Tuner.getChannel(Unknown Source) [SDRTrunk.jar:na]
        at source.tuner.TunerManager.getSource(Unknown Source) [SDRTrunk.jar:na]
        at source.SourceManager.getSource(Unknown Source) [SDRTrunk.jar:na]
        at controller.channel.ProcessingChain.updateSource(Unknown Source) [SDRTrunk.jar:na]
        at controller.channel.ProcessingChain.start(Unknown Source) [SDRTrunk.jar:na]
        at controller.channel.Channel.start(Unknown Source) [SDRTrunk.jar:na]
        at controller.channel.Channel.enableChanged(Unknown Source) [SDRTrunk.jar:na]
        at controller.channel.Channel.setResourceManager(Unknown Source) [SDRTrunk.jar:na]
        at controller.channel.ChannelNode.init(Unknown Source) [SDRTrunk.jar:na]
        at controller.site.SiteNode.init(Unknown Source) [SDRTrunk.jar:na]
        at controller.system.SystemNode.init(Unknown Source) [SDRTrunk.jar:na]
        at controller.system.SystemListNode.init(Unknown Source) [SDRTrunk.jar:na]
        at playlist.PlaylistNode.init(Unknown Source) [SDRTrunk.jar:na]
        at playlist.PlaylistNode.loadPlaylist(Unknown Source) [SDRTrunk.jar:na]
        at controller.ConfigurationControllerModel.init(Unknown Source) [SDRTrunk.jar:na]
        at gui.SDRTrunk.initGUI(Unknown Source) [SDRTrunk.jar:na]
        at gui.SDRTrunk.<init>(Unknown Source) [SDRTrunk.jar:na]
        at gui.SDRTrunk.main(Unknown Source) [SDRTrunk.jar:na]
13:27:54.242 DEBUG s.t.r.RTL2832TunerController - rtl2832 [00000101] - starting sample fetch thread
13:27:54.245 DEBUG d.p.a.IMBETargetDataLine - Constructing instance of TDL
13:27:54.245 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_binary_messages.log
13:27:54.247 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_decoded_messages.log
13:27:54.250 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_call_events.log
13:27:54.252 INFO  gui.SDRTrunk - Channel [OC Simu VC] - - started audio recording [C:\Users\mtindor\SDRTrunk\recordings
\20150404_132754_OC Simu VC_audio.wav]
13:27:54.320 DEBUG d.p.a.IMBETargetDataLine - Constructing instance of TDL
13:27:54.320 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_CC_binary_messages.log
13:27:54.322 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_CC_decoded_messages.log
13:27:54.325 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_CC_call_events.log
13:27:54.390 DEBUG d.p.a.IMBETargetDataLine - Constructing instance of TDL
13:27:54.392 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_binary_messages.log
13:27:54.392 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_decoded_messages.log
13:27:54.395 INFO  eventlog.EventLogger - Creating log file:C:\Users\mtindor\SDRTrunk\event_logs\20150404_132754_WVSIRN_
OC_Simu_OC_Simu_VC_call_events.log
13:27:54.397 INFO  gui.SDRTrunk - Channel [OC Simu VC] - - started audio recording [C:\Users\mtindor\SDRTrunk\recordings
\20150404_132754_OC Simu VC_audio.wav]
13:27:54.415 INFO  gui.SDRTrunk - starting main application gui

Any ideas?

Mike

[DSheirer]

Mike,
Pull down the latest svn update from the SDRTrunk repo ... there's a change in the window's batch file.

The change is already included in the compiled version in the downloads folder.

[mtindor]

Originally Posted by DSheirer

Mike,
Pull down the latest svn update from the SDRTrunk repo ... there's a change in the window's batch file.

The change is already included in the compiled version in the downloads folder.

Thank you, Denny. That did it. Onward and upward!

Mike

[mtindor]

It's all working. I've got decoded audio (channels set as P25 Phase 1 --> LSM). Looking good. I'm running two dongles now.

Should it be automatically following voice, or is that still not implemented yet? If I click on the channel that has voice, it plays. Just wondering if it should automatically be following voice?

Mike

[DSheirer]

Originally Posted by mtindor

Should it be automatically following voice, or is that still not implemented yet?
Mike

That's not implemented yet.

I'm reworking the audio distribution system first, so that you can simply start the decoders and then call audio will be automatically routed to speakers, recorders, streams, etc. based on talkgroups or however you want to set it up.

[mtindor]

Originally Posted by DSheirer

That's not implemented yet.

I'm reworking the audio distribution system first, so that you can simply start the decoders and then call audio will be automatically routed to speakers, recorders, streams, etc. based on talkgroups or however you want to set it up.

Wonderful. And I'm sorry for asking that question, as I see the answer is in you wiki as far as the current state of APCO25 automatic voice following. I should RTFM. Excitement gets the better of me sometimes.

It's really working great. I'm not sure if [you feel] there is still work to e done on decoding, or if you believe it to be spot on now. I only say that because I dont' always get completely clear decode. But I suppose that could be because these NoElect Nano dongles do not maintain a consistent temperature for me and as such drift. That's likely the reason.

I set up an Alias list and put some talkgroups in, and they are all displaying nicely. And I like that you can click on an individual channel and see the events logged on that channel.

Screenshot below for anybody who wants to see P25 working. Obviously you cannot hear the decoded audio but it is indeed decoding.

Thanks!

mike

[DSheirer]

7 channels ... nice!

Originally Posted by mtindor

I dont' always get completely clear decode. But I suppose that could be because these NoElect Nano dongles do not maintain a consistent temperature for me and as such drift.

I'm not happy with the voice decodes yet. There are two things that I want to add that might improve the audio some more. There's a new CIC decimation filter that I've been working on. The one in sdrtrunk right now will gradually auto-mute itself if you set the filter order higher than one. This filter affects the quality of the channel samples that are provided to the decoder.

The other thing is Auto Frequency Control for LSM. SDRTRunk is using the LSM decoder from OP25 which is able to track some frequency deviation, but I want to add an automatic adjuster like the C4FM decoder is using, that can auto adjust the frequency offset once it exceeds the decoder's ability to track it.

[bassjunkie]

Been trying to get SDRtrunk working today and have hit a bit of a brick wall, hoping this is the right thread for it.

Have configured an MPT-1327 system and can see it definitely working, traffic shows up in events and messages, and the channel window pops up with new channels whenever a call is initiated. I definitely have the control channel selected (with the yellow border thingy), and the voice channels aren't out of range of the receiver, however I'm not getting any audio output at all on the system. From what I can see it should be working fine.

Have tested with an NFM channel and it comes through beautifully, confirmed the offset is all good, and can see the signal right there. Ticking the record checkbox in the control channel's settings doesn't help, though it does produce some strange wav files that only have the audio of the control channel itself, and mysteriously grow in file size despite staying the same length. Have tried both the latest release and compiled from SVN, no difference there.

Might see if I can dig up one of the old builds to see if the pre P25 releases work, in the meantime would welcome any suggestions for troubleshooting.

[DSheirer]

Originally Posted by bassjunkie

Been trying to get SDRtrunk working today and have hit a bit of a brick wall, hoping this is the right thread for it.

Have configured an MPT-1327 system and can see it definitely working, traffic shows up in events and messages, and the channel window pops up with new channels whenever a call is initiated. I definitely have the control channel selected (with the yellow border thingy), and the voice channels aren't out of range of the receiver, however I'm not getting any audio output at all on the system. From what I can see it should be working fine.

In the decoding channels window you normally select a channel and can hear the audio output from the channel. The MPT-1327 decoder detects that it is monitoring a control channel and will auto-squelch the audio, making it so that you won't hear any audio from the channel (the channel state changes to CONTROL)

When a call takes place, there should be an additional sub-panel that appears below the control channel panel that reflects the call in progress. You can then click on that sub-panel to hear the audio from that call.

These steps for listening to the traffic call audio are clunky ... and the main reason why I haven't added traffic channel following for P25 calls yet. I'm redesigning the audio management subsystem to improve the functionality and make it easier for users to manage the audio streams from multiple channels.

Denny

[bassjunkie]

Originally Posted by DSheirer

In the decoding channels window you normally select a channel and can hear the audio output from the channel. The MPT-1327 decoder detects that it is monitoring a control channel and will auto-squelch the audio, making it so that you won't hear any audio from the channel (the channel state changes to CONTROL)

When a call takes place, there should be an additional sub-panel that appears below the control channel panel that reflects the call in progress. You can then click on that sub-panel to hear the audio from that call.

These steps for listening to the traffic call audio are clunky ... and the main reason why I haven't added traffic channel following for P25 calls yet. I'm redesigning the audio management subsystem to improve the functionality and make it easier for users to manage the audio streams from multiple channels.

Denny

Thanks for the quick reply That's pretty much what I'm seeing, except when I click on the auto-created traffic channel when it appears, there's still no audio.

I'll fire it back up and see if I can grab a screenshot, for science.

Edit: http://imgur.com/a/lJrv3

First is with control selected, second with the talk channel selected, neither provide audio.

[jazzbassNick]

Hi Denny,

Not sure what I'm not doing correctly, but the log shows all 3 of the messages on the Troubleshooting page for JMBE.

When I launch it, I get the "Available Audio Converter class ( along with a couple of others) in the terminal window.
When a call shows up on the channel I have selected, the log shows the IMBE library loaded, then immediately I get the "could NOT find load/IMBE" message.

Thoughts?

Thanks,
N

[DSheirer]

Originally Posted by jazzbassNick

Hi Denny,

Not sure what I'm not doing correctly, but the log shows all 3 of the messages on the Troubleshooting page for JMBE.

When I launch it, I get the "Available Audio Converter class ( along with a couple of others) in the terminal window.
When a call shows up on the channel I have selected, the log shows the IMBE library loaded, then immediately I get the "could NOT find load/IMBE" message.

Thoughts?

Thanks,
N

Can you send me the application log file showing those log messages?

Denny

[DSheirer]

I posted a new build with several improvements to the P25 LSM/CQPSK decoder:

- Improved gain control
- Slight change to gardner symbol timing calculations
- Auto-detect and correct costas-loop phase lock errors
- Faster audio buffer processing to try reducing audio drops

Note: NO update required for the JMBE audio converter library - continue to use version 0.1.1

The audio quality still seems tinny sounding. I'm trying to track down what might be causing the issue in the audio decoder library.

Denny

[DSheirer]

I posted a new build (0.1.3) of sdrtrunk and updated the JMBE library (0.1.3).

Features:
-Supports P25 audio conversion to 48 kHz sample rate for better compatibility with some sound cards

Resolves:
-Significant updates to the JMBE P25 audio library to improve audio quality and reduce dropouts
-P25 C4FM channel frequency tracking issues

Issues:
-Multi-path impact on P25 LSM/CQPSK decodes - still working this issue.
-P25 C4FM frequency drift tracking - sometimes when you change tuner frequency, one or more of the P25 decoders will stop decoding - WORKAROUND: change the tuner frequency slightly up/down

Denny

[mtindor]

Originally Posted by DSheirer

I posted a new build (0.1.3) of sdrtrunk and updated the JMBE library (0.1.3).

Features:
-Supports P25 audio conversion to 48 kHz sample rate for better compatibility with some sound cards

Resolves:
-Significant updates to the JMBE P25 audio library to improve audio quality and reduce dropouts
-P25 C4FM channel frequency tracking issues

Issues:
-Multi-path impact on P25 LSM/CQPSK decodes - still working this issue.
-P25 C4FM frequency drift tracking - sometimes when you change tuner frequency, one or more of the P25 decoders will stop decoding - WORKAROUND: change the tuner frequency slightly up/down

Denny

Thanks for your effort, Denny. I'll give this a try later today.

I'm making a presumption, but if you truly have LSM support built in [ala the OP25 LSM code], there wouldn't be an issue with multipath impact on P25 LSM/CQPSK decode because that is specifically what that code was meant to address -- no? I've tested out the OP25 quite a bit on LSM systems, and its really a stellar performer. Seems to me if that your code is handling LSM based upon OP25, multipath should be moot since LSM support automatically implies that there is going to be multipath and thus deals with that.

Mike

[DSheirer]

Originally Posted by mtindor

I'm making a presumption, but if you truly have LSM support built in [ala the OP25 LSM code], there wouldn't be an issue with multipath impact on P25 LSM/CQPSK decode because that is specifically what that code was meant to address -- no? I've tested out the OP25 quite a bit on LSM systems, and its really a stellar performer. Seems to me if that your code is handling LSM based upon OP25, multipath should be moot since LSM support automatically implies that there is going to be multipath and thus deals with that.
Mike

Mike,

I've mostly mirrored the OP25 LSM code. In studying the code, it looks like OP25 uses a feed forward gain control to counter multi-path impact on signal magnitude (amplitude). I'm using the same gain control yet still having issues keeping the Gardner loop consistently locked on symbol center without occasional symbol rollovers.

I recently built OP25 for comparison testing and OP25 is also unable to provide good (consistent) decodes of the local CNYICC LSM channels.

A feed-forward gain control doesn't address multi-path induced phase distortion -- it restores signal amplitude close to unity. I'm working on an equalizer to see if that improves decode rates.

Please let me know if the latest build is better/worse than the last one you tried.

Thanks,

Denny

[mtindor]

Denny,

Thanks for the explanation. Understand, I'm an idiot. So much of that was over my head. I'll take your word for it

Tomorrow afternoon I should get a chance to test the latest SDRTrunk build. They just fired up the local county P25 LSM site today, so I'll try it out. I'll also try it out on more problematic LSM that I try to monitor. I'll let you know what I find out.

Mike