Complex File(I/Q) Source with gqrx

[Kavitha Subramaniam]

Hi ,

Have anyone aware of how to test Complex File(I/Q) with gqrx.

When i run gqrx, output is simply aUaUaUaUaUaUaU. I don't know what is happening.

any solution???

Thanks in advance!!!!

[Kavitha Subramaniam]

I found the reason why output is aUaUaUaU , problem is due to underrun (not enough data to play) .

My Complex Sampled (IQ) file is 26.1 MB in size.When demodulate(Narrow FM ) it ,only 168 KB valid output...

any tips???

[Kavitha Subramaniam]

After enabling debug mode in gqrx, getting following output

kavitha@ubuntu:~/gnuradio-3.7.3/gqrx-2.2.0/build$ ./gqrx
linux; GNU C++ version 4.6.3; Boost_104601; UHD_003.007.000-0-unknown

Gqrx software defined radio receiver 2.2

Controlport disabled
No user supplied config file. Using "default.conf"
"/home/kavitha/.config/gqrx/default.conf" deleted
MainWindow Configuration

    LNB Local oscillator = 0
    Hardware frequency = 0
    FFT Average  = 0.5
    Filter Shape =  1
    RF Frequency = 144500000

Receiver Setup

    Input rate = 96000
    Audio rate = 48000
    Rf frequency = 1.448e+08
    Filter Offset = 0


UHD Error:
    Device discovery error: Connection refused


IQ FILE = /dev/random
frequency = 4.28e+08
Sampling rate = 96000
Using Volk machine: sse4_2_32_orc
IQ DCR alpha: 1.04166e-05
Using audio backend: auto
New filter offset: 0 Hz
Loading configuration from: "default.conf"
Configuration file: "/home/kavitha/.config/gqrx/default.conf"
Saving configuration to: "default.conf"
Error saving configuration to "/home/kavitha/.config/gqrx/default.conf"
No change in output device:
  old:
  new:
setFreqCorr : 0 ppm
New LNB LO: 0 Hz
updateFrequencyRange failed fetching new frequency range
updateFrequencyRange failed fetching new frequency range
setFftRate to "15 fps"
New FFT rate: 15 Hz
setFftSize to "2048"
Changing baseband FFT size to 2048
Launching I/O device editor
Configure I/O devices.

UHD Error:
    Device discovery error: Connection refused
CIoConfig : Available input devices:
    0 : "RFSPACE SDR-IQ Receiver"
    1 : "RFSPACE SDR-IP Receiver"
    2 : "RFSPACE NetSDR Receiver"
    3 : "RTL-SDR Spectrum Server"
    4 : "Complex Sampled (IQ) File"
New input device selected: 4
  Label: "Complex Sampled (IQ) File"
  Devstr: "file=/path/to/your/file,freq=100e6,rate=1e6,repeat=true,throttle=true"
saveConfig
saveSettings *** FIXME_ SQL on/off
New FFT rate: 15 Hz
Loading configuration from: "/home/kavitha/.config/gqrx/default.conf"
Configuration file: "/home/kavitha/.config/gqrx/default.conf"

UHD Error:
    Device discovery error: Connection refused


IQ FILE = /home/kavitha/gnuradio-3.7.3/gr-osmosdr/grc/fminput_192k_16bit.wav
frequency = 1e+08
Sampling rate = 192000
No change in output device:
  old:
  new:
setFreqCorr : 0 ppm
New LNB LO: 0 Hz
updateFrequencyRange failed fetching new frequency range
updateFrequencyRange failed fetching new frequency range
../qtgui/dockrxopt.cpp currentMaxdev FIXME
Filter preset for mode 3 LO: -5000 HI: 5000
Genrating taps for new filter LO:-5000 HI:5000 TW:1000
Required number of taps: 115
setFftRate to "15 fps"
New FFT rate: 15 Hz
setFftSize to "2048"
No change in output device:
  old:
  new:
New FFT rate: 15 Hz
New FFT rate: 15 Hz
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
Force RX reconf (jerky dongle workarond)...
No change in output device:
  old:
  new:
../qtgui/dockrxopt.cpp currentMaxdev FIXME
Filter preset for mode 3 LO: -5000 HI: 5000
Genrating taps for new filter LO:-5000 HI:5000 TW:1000
Required number of taps: 115
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
aUaUaUNo audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
aUNo audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
aUaUNo audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.
No audio FFT data.

 

[Alexandru Csete]

The input file must have "complex float" format not integer format. I
assume "fminput_192k_16bit.wav" means signed 16bit integer. I don't
know if that's explains what you are observing. You don't provide much
info.

You can try to build the latest source from git and use gqrx own I/Q
file recorder player.

Alex

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[Kavitha Subramaniam]

Hi Alex,
 
 
 I have generated a wav file(sample rate=192k and sample resolution = 16bit) using Spark Modulator.

  I have converted to gnuradio cfile (using GRC)
  
 "wav source" => "float to complex" -> "file sink"

  Then  I opened that cfile file in gqrx (Complex Sampled IQ file) and then demodulate that file(Narrow band FM).
 
 

 I am getting output like  below,

IQ FILE = /home/kavitha/fm_input.cfile

aUaUaUaUaUNo audio FFT data.
No audio FFT data.
aUaUaUaUNo audio FFT data.
aUaUaUNo audio FFT data.
aUaUaUaUNo audio FFT data.

No audio FFT data.
aUaUNo audio FFT data.
No audio FFT data.
aUaUNo audio FFT data.
No audio FFT data.

aUaUaUaUNo audio FFT data.
No audio FFT data.
aUaUaUaUNo audio FFT data.

No audio FFT data.
aUaUaUNo audio FFT data.
No audio FFT data.

aUaUNo audio FFT data.
aU


Details for your Info:

 Ubuntu12.04 ,gqrx - 2.2 , gnuradio - 3.7.3, QT- 4.7.3




 

 

 

[Alexandru Csete]

Make sure you use the correct sample rate in both the device string
and the input settings. I have no other ideas what could be wrong.

Alex

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[Kavitha Subramaniam]

Hi Alex,

Firstly ,Thanks for your reply.

I want to know why " No audio FFT data" keeps on printing. Is there any way  to check this???  While printing aU only I can hear some sound.

The way I have tested  Complex Sampled(IQ) file with gqrx is correct or not (I have mentioned in previous posting) ??? Any Tips???

[Alexandru Csete]

On Fri, May 30, 2014 at 8:52 AM, Kavitha Subramaniam
<kavipra...@gmail.com> wrote:
>
> I want to know why " No audio FFT data" keeps on printing. Is there any way
> to check this??? While printing aU only I can hear some sound.
>

aU means audio underrun, comes from the gnuradio audio sink, and
happens when samples are not delivered fast enough to the sound card.

No audio FFT data is basically the same except that it comes from the
gqrx audio FFT code.

The reason can be incorrect sample rates, CPU overload or the gnuradio
runtime not working properly on your computer..

Alex

[Kavitha Subramaniam]

Finally, I can hear audio but Audio is very very slow.

[Kavitha Subramaniam]

I couldn't resolve slow audio problem...any tips???

[Alexandru Csete]

On Tue, Jun 3, 2014 at 8:50 AM, Kavitha Subramaniam
<kavipra...@gmail.com> wrote:
>
> I couldn't resolve slow audio problem...any tips???
>

Yes, I have a tip for you, see here:
http://www.catb.org/esr/faqs/smart-questions.html

The answers you get will never be better than the questions you ask.
This is a spare time project and don't expect to get help with
everything within a matter of hours. Poking for answer and posting the
same question several places is only going to annoy people.

Alex