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DSD+ - No Audio output

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#1
I have installed AirSpy, VB Cable and DSD+ on my Windows 10 operating system. I checked to hear any normal audio signals using AirSpy, and I could perfectly hear the local HAM repeater. I then tune into a frequency having a digital transmission on Air Spy, and I pipe in the audio to VB Cable Input.

I use the below command to start DSD+
---
DSDPlus -i2M -o1M -fa -e -O NUL

Below are the status messages which come on the console
=======
DSD+ 1.101pt
Auto-muting encrypted voice
NOT saving synthesized audio to DSDPlus.mp3
0 frequency records loaded
0 radio records loaded
0 group records loaded
0 site records loaded
0 network records loaded

audio input device #1 = 'Microphone (Realtek High Defini'
audio input device #2 = 'CABLE Output (VB-Audio Virtual '

audio output device #1 = 'Speaker/HP (Realtek High Defini'
audio output device #2 = 'CABLE Input (VB-Audio Virtual C'

audio input device #2 (CABLE Output (VB-Audio Virtual ) initialized
audio output device #1 (Speaker/HP (Realtek High Defini) initialized

D-STAR decoding enabled
NXDN4800 decoding enabled
NXDN9600 decoding enabled
DMR/MotoTRBO decoding enabled
P25 Phase 1 decoding enabled
X2-TDMA decoding enabled
ProVoice decoding enabled

Mono audio decoding initiated; press Esc to exit...
=======

I understand that DSD+ would read sound from the CABLE Output and ideally should push the processed audio to my laptop speakers. How ever, when a digital signal is received;
1. I see the wave form changing based on the audio signal
2. But I do NOT hear any audio (processed or unprocessed) on the laptop speakers. The DSD+ console also is not throwing up any more messages indicating that it has received an audio input and identified the digital mode.

I am new to this; so request any expert to help me. Have I missed out any step?
 
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#3
a) it has to be a digital mode that DSD+ decodes
I would try to attach a screen image of the signals (as I see on the Air Spy water fall). At the first glance it looked like a P25 or MotoTRBO mode. Also does DSD+ sharp throw any warning when it finds a signal which it does not recognize, or does it ignore it completely? I also don't get any audio output (not even the original signal). Is that also the expected behavior?

b) demodulation mode, bandwidth and audio filtering have to be set properly in SDR#[/QUOTE]
Narrow FM (NFM), band width of 13,000 and I have enabled audio filtering - mainly to reduce the static noise, when there is no transmission being happening. I would try to attach a screen image of the settings I have made.

Thank you for your response :).
 
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#4
I would try to attach a screen image of the signals (as I see on the Air Spy water fall). At the first glance it looked like a P25 or MotoTRBO mode. Also does DSD+ sharp throw any warning when it finds a signal which it does not recognize, or does it ignore it completely?
Ignore.


I also don't get any audio output (not even the original signal). Is that also the expected behavior?
Expected.


Narrow FM (NFM), band width of 13,000 and I have enabled audio filtering
There's your problem. DSD+ needs raw unfiltered audio.
 
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#5
slicerwizard said:
There's your problem. DSD+ needs raw unfiltered audio.
I have attached two images from AirSpy ;
1) the settings I have on AirSpy to listen to the audio. When I took this screen capture, I was pushing the audio to my laptop speakers (and not to VC Cable).
2) the wave form of the signals as shown in AirSpy waterfall.

I do have the audio file recorded as well, but the file size limits do not allow me to upload the same.

Am I on the right path so far? :).
 

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dave3825

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#6
I your not using the dsdplus plug in, or do not have sdr# audio output set for vbcable, then your not getting anything from sdr# to vbcable.

For now, try clicking stop on sdr# Go into the audio tab of sdr# and for output, select vbcable. Then click play . Tune to the digital channel in sdr# and see if you get any movement on dsdplus..
 
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#7
dave3825 said:
I your not using the dsdplus plug in, or do not have sdr# audio output set for vbcable, then your not getting anything from sdr# to vbcable.
Let me see if I can download the plug-in. I was not able to find it earlier. I am attaching a screen image of settings I have done on AirSpy/SDR #. So that audio Output from SDR# is piped to VC Cable input.

For now, try clicking stop on sdr# Go into the audio tab of sdr# and for output, select vbcable. Then click play . Tune to the digital channel in sdr# and see if you get any movement on dsdplus.
I have attached a screen grab showing SDR#, and the DSD+ modules. I can see the digital signal on the water fall, and also the sine wave moving in the graph window of DSD+. The other DSD+ windows show no reactions what so ever.

Are the steps which I have done, correct to this point? Thank you for the suggestions :).
 

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Joined
Nov 21, 2018
Messages
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Location
India
#8
PROBLEM SOLVED! The DSD+ plugin saved my day. Looks like my "Input & Output" settings were not correct. And now I am able to copy the digital signals identified as DMR (DCC 6). Now trying to understand the log messages seen on the DSD+ command window and on the DSD+ Event log window.

If there is any article which explains how to interpret the log messages, request you to provide a link to the same.

Thank you every one!! :)
 
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#10
RF gain is too high. AF gain is too high. And it's probably not something that DSD+ decodes. It could be some sort of telemetry, which a speech decoder isn't going to touch. Find some other digital transmissions.
 
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#11
It was incorrect settings done by me. With the changed settings I am able to decode the DMR signals. It is most likely a DMR Tier-II network, with two slots (one voice and one data). Now trying to find out how I can only focus on slot 1 listening. I did observe that when there is data on both slot 1 and slot 2, some voice messages are getting clipped. Also is there any program available to Decode the DATA which is transmitted on Slot 2?
 
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