Re: [Discuss-gnuradio] Having issues getting APT-DECODER Sample working

[Tommy James Tracy II]

On 10/7/12 7:23 PM, Patrik Tast wrote:
> You will have to investigate more.
> 
> Try download/build the
> <http://www.qsl.net/5b4az/pkg/apt/wxapt/wxapt.html> or (I use)
> <http://atpdec.sourceforge.net/>
> 
> It shouldn't be that hard...
> 
> Patrik

Yes, thank you. I would run wxapt or atpdec if my goal was to decode the
APT images, but my goal is different.

I would like to take a gnuradio program that is currently running on one
machine, and split it among several computers. I chose this program
because A it does not require a USRP (I feed in a straight RAW file), B
it is non trivial and has a branch; it is also fairly compute intensive
when compared to other 'easier' gnuradio applications.

My goal is to get APT decoding to work in gnuradio without using any
other programs.

Thanks again!

Tom
> 
> 
> 
> 
> On Sun, 2012-10-07 at 18:31 -0400, Tommy James Tracy II wrote:
>> On 10/7/12 4:24 PM, Patrik Tast wrote:
>>> Hi Tommy,
>>>
>>>> and opened it in the file source, and ran the gnuradio program. If I do
>>>> a cat of the output.dat file, I found that there was nothing in it. I
>>>> then opened it in VIM and found the following string repeated:
>>>>
>>>> "address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@^@"
>>>>
>>>> I think those aren't valid characters so maybe the float_to_uchar was
>>>> unsuccessful.
>>>>
>>>> Did you use a different algorithm? Do I need to multiply the input to
>>>> fit it between the 0->1v range before the 255 multiplier?
>>>>
>>>
>>> oooh...I suspect that you have something set wrong now?
>>> I can not understand what you are doing.
>>>
>>
>>
>> I have attached an image of my GRC flowgraph. It is meant to be an exact
>> copy of the one presented at the following website:
>> http://www.oz9aec.net/index.php/gnu-radio/gnu-radio-blog/440-simple-apt-decoder-prototype
>>
>> I have either made a mistake, the website has a non-functional flowgraph
>> on it, or the input WAV file is incorrect; I think you verified the WAV
>> file.. so i think it is one of the first two.
>>
>>> To test I downloaded
>>> http://www.poes-weather.com/~patrik/apt/audio/24_June_2009/090724_032529_NOAA_18.wav
>>>
>>> Screenshot while decoding using my software
>>> http://poes-weather.com/~patrik/tmp/Screenshot%20from%202012-10-07%
>>> 2023:08:09.png
>>
>> From the looks of the screenshot you sent, you are using a different
>> application. Do you use Gnuradio under the hood?
>>
>>>
>>> This should be decodable using any software. 
>>> I suspect you are on the wrong track now.
>>>
>>> Patrik
>>
>> Thanks again,
>> Tom
>>>
>>>
>>>
>>> On Sun, 2012-10-07 at 13:26 -0400, Tommy James Tracy II wrote:
>>>> On 10/7/12 6:44 AM, Patrik Tast wrote:
>>>>> Hi Tommy,
>>>>>
>>>>>> What do you mean by source file sink?
>>>>> I thought you were using GRC and if the file was downloaded from me I
>>>>> know it is (recorded) in 8bit 2.4kHz carrier.
>>>>>
>>>>> You will find a lot of hits regarding APT when googling and be very
>>>>> objective, most are copy -> copy....
>>>>>
>>>>> Sure we can/could convert it to 16, 32, 64, 128 bit etc.
>>>>> The fact is that APT is 8bit so why change it to 32bit?
>>>>> The result will be a 4x bigger file almost full of zeroes since again
>>>>> only 8 bits are used (gray scale). If recorded as 16bit it will be of
>>>>> course 2x bigger than required since max is again 0x0000 ffff.
>>>>> In this case you wont win if more bits are used.
>>>>>
>>>>> APT bandwidth is ~30kHz @ 137Mhz
>>>>>
>>>>> Some samples here, don't convert:
>>>>> http://www.poes-weather.com/~patrik/apt/audio/24_June_2009/
>>>>> Images & tests:
>>>>> http://www.poes-weather.com/index.php?view=article&id=100%
>>>>> 3Asunday-6th-july-2008&Itemid=73&option=com_content
>>>>>
>>>>> 24/7 images:
>>>>> http://www.poes-weather.com/~patrik/apt/logs/daily/
>>>>
>>>> Thank you for the reply; I took one of your 8bit samples:
>>>>  
>>>> www.poes-weather.com/~patrik/apt/audio/24_June_2009/090723_213010_NOAA_17.wav
>>>>
>>>> and opened it in the file source, and ran the gnuradio program. If I do
>>>> a cat of the output.dat file, I found that there was nothing in it. I
>>>> then opened it in VIM and found the following string repeated:
>>>>
>>>> "address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@address@hidden@^@"
>>>>
>>>> I think those aren't valid characters so maybe the float_to_uchar was
>>>> unsuccessful.
>>>>
>>>> Did you use a different algorithm? Do I need to multiply the input to
>>>> fit it between the 0->1v range before the 255 multiplier?
>>>>
>>>> Sincerely,
>>>> Tommy Tracy II
>>>>
>>>>>
>>>>> Patrik
>>>>>
>>>>> On Sat, 2012-10-06 at 22:43 -0400, Tommy James Tracy II wrote:
>>>>>> On 10/6/12 5:37 PM, Patrik Tast wrote:
>>>>>>> Hi Tommy,
>>>>>>>
>>>>>>> Most likely the file (wav) you have found is in 8bit.
>>>>>>> Try to adjust your source file sink.
>>>>>>>
>>>>>>> Patrik
>>>>>>>
>>>>>> Dear Patrik,
>>>>>>
>>>>>>  What do you mean by source file sink?
>>>>>> I used soundconverter to convert the WAV file to mp3, and then back to a
>>>>>> 32-bit sampled WAV. I tried it, and it failed with the same error.
>>>>>>
>>>>>> I also tried to use FFT with byte input, but that doesn't exist. The
>>>>>> only options are float or complex.
>>>>>>
>>>>>> Again thank you!
>>>>>>
>>>>>> Tom
>>>>>>
>>>>>>> On Sat, 2012-10-06 at 16:51 -0400, Tommy James Tracy II wrote:
>>>>>>>> Dear Gnuradio,
>>>>>>>>
>>>>>>>>        I'm trying to run the following gnuradio program:
>>>>>>>> http://www.oz9aec.net/index.php/gnu-radio/gnu-radio-blog/440-simple-apt-decoder-prototype
>>>>>>>>
>>>>>>>> I found a WAV file online to use as the input to the APT-Decoder, so I
>>>>>>>> fed it in. Unfortunately, the output file resulted in a bunch of '^@'
>>>>>>>> characters instead of the expected ASCII(0) through ASCII(255).
>>>>>>>>
>>>>>>>> To make sure that the Audio file source was actually producing an
>>>>>>>> output, I hooked up an AUDIO_SINK block between the File Source and the
>>>>>>>> Band Pass Filter. I heard the expected APT sound.
>>>>>>>>
>>>>>>>> I then proceeded to drop in a WX GUI FFT Sink, and kept getting the
>>>>>>>> following error:
>>>>>>>>
>>>>>>>> Has anyone seen this?
>>>>>>>> -----
>>>>>>>>
>>>>>>>> Traceback (most recent call last):
>>>>>>>>   File
>>>>>>>> "/usr/local/lib/python2.7/dist-packages/gnuradio/wxgui/plotter/plotter_base.py",
>>>>>>>> line 187, in _on_paint
>>>>>>>>     for fcn in self._draw_fcns: fcn[1]()
>>>>>>>>   File
>>>>>>>> "/usr/local/lib/python2.7/dist-packages/gnuradio/wxgui/plotter/plotter_base.py",
>>>>>>>> line 59, in draw
>>>>>>>>     self._draw()
>>>>>>>>   File
>>>>>>>> "/usr/local/lib/python2.7/dist-packages/gnuradio/wxgui/plotter/grid_plotter_base.py",
>>>>>>>> line 407, in _draw_point_label
>>>>>>>>     label_str = self._populate_point_label(x_val, y_val)
>>>>>>>>   File
>>>>>>>> "/usr/local/lib/python2.7/dist-packages/gnuradio/wxgui/plotter/channel_plotter.py",
>>>>>>>> line 151, in _populate_point_label
>>>>>>>>     label_str += '\n%s: %s'%(channel, common.eng_format(y_value,
>>>>>>>> self.y_units))
>>>>>>>>   File
>>>>>>>> "/usr/local/lib/python2.7/dist-packages/gnuradio/wxgui/plotter/common.py",
>>>>>>>> line 82, in eng_format
>>>>>>>>     coeff, exp, prefix = get_si_components(num)
>>>>>>>>   File
>>>>>>>> "/usr/local/lib/python2.7/dist-packages/gnuradio/wxgui/plotter/common.py",
>>>>>>>> line 48, in get_si_components
>>>>>>>>     exp = get_exp(num)
>>>>>>>>   File
>>>>>>>> "/usr/local/lib/python2.7/dist-packages/gnuradio/wxgui/plotter/common.py",
>>>>>>>> line 37, in get_exp
>>>>>>>>     return int(math.floor(math.log10(abs(num))))
>>>>>>>> ValueError: cannot convert float NaN to integer
>>>>>>>>
>>>>>>>> -----
>>>>>>>>
>>>>>>>> I think this means that the WAV file (float output) is producing NAN
>>>>>>>> outputs. Is there any way that I can remove those? Anyone have any
>>>>>>>> success doing this before?
>>>>>>>>
>>>>>>>> Thanks in advance!
>>>>>>>> _______________________________________________
>>>>>>>> Discuss-gnuradio mailing list
>>>>>>>> address@hidden
>>>>>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Discuss-gnuradio mailing list
>>>>>>> address@hidden
>>>>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
> 
> 


-- 
  Tommy J. Tracy II
 Computer Engineering
University of Virginia

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