Re: [Discuss-gnuradio] Modulation problem ?

[Steven Clark]

hex 00 and 01 are not visible characters, which is why you aren't
seeing anything. Looking at the data, it looks like unpacked data (ie
only the bottom bit of each byte is being used). If you convert it
back to packed data, it may be you'll get your original message back.
GNURadio has a unpacked_to_packed block for this purpose.

On Tue, May 20, 2008 at 12:53 PM, irene159 <address@hidden> wrote:
>
>
> Steven Clark-2 wrote:
>>
>> This is not surprising. It is likely that you are getting some initial
>> garbage (non-standard-ascii characters) coming out, or that you have
>> some bit errors.
>>
>> Don't open it in gedit. Try:
>> python
>> f = open('Resultat.txt')
>> d = f.read()
>> f.close()
>> print(len(d))
>> print(d)
>> (or if d is really long, print(d[:50]))
>>
>
>
> When I tried this and
>       $ cat Resultat.txt
> or even
>       $ less Resultat.txt
> on the Terminal I didn't see anything at first but copying what seemed empty
> into a file, I got:
>
>
>>>>
>
>
>
> George Nychis wrote:
>>
>> I'm on a mobile so I can't look at the files. But look at the file
>> sink type of your final output and the block that feeds it. My guess
>> is that its of type float or something where each float represents a
>> bit in "unpacked" binary format.... Not the bit packed ASCII you are
>> expecting.
>>
>
> The file sink type of my final output is gr.sizeof_char and the block that
> feeds it is
> objDemod = dqpsk.dqpsk_demod() whose output type is a stream of bits packed
> 1 bit per byte (LSB):
>     objDemod = dqpsk.dqpsk_demod()
>     fg.connect(gr.file_source(gr.sizeof_gr_complex, "Modulated.dat"),
> objDemod,
>
> gr.file_sink(gr.sizeof_char,"Resultat.txt"))
> Is this correct?
> I have seen an example of almost identical code working with dbpsk instead
> of dqpsk[1].
>
> However there might be an important difference (I am only a beginner and I
> am not really sure of the impact it can have). In DBPSK last block (the
> block feeding the result file) is:
> self.unpack = gr.unpacked_to_packed_bb(self.bits_per_symbol(),
> gr.GR_MSB_FIRST)
>
> While as for DQPSK, it is:
> self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
>
>
>
> Ed Criscuolo-2 wrote:
>>
>> Eric Blossom wrote:
>>> How about:
>>>
>>>   $ cat Resultat.txt
>>>
>>> or
>>>
>>>   $ less Resultat.txt
>>>
>>
>>
>> Or :
>>
>> od -tx1 Resultat.txt | less
>>
>>
>> to get hex bytes to see what's going on at a binary level.
>>
>>
>> @(^.^)@  Ed
>>
>>
>
> Result was :
>
>
> 0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 01
> 0000040 00 00 00 00 00 00 01 01 01 01 01 01 01 01 00 00
> 0000060 00 00 00 00 00 01 00 00 00 01 01 01 00 01 00 00
> 0000100 01 01 01 00 00 01 00 01 00 01 00 01 00 00 01 00
> 0000120 00 00 00 00 00 01 00 01 00 00 01 00 00 01 01 00
> 0000140 00 00 00 01 00 01 01 00 00 01 00 00 00 01 01 00
> 0000160 01 00 00 01 00 01 01 00 01 01 01 01 00 00 00 00
> 0000200 01 00 01 00 00 00 00 00 01 00 01 00 00 01 00 01
> 0000220 00 00 00 00 00 01 01 01 00 00 01 00 00 01 01 00
> 0000240 01 01 01 01 00 01 01 00 01 00 01 00 00 01 01 00
> 0000260 00 01 00 01 00 01 01 00 00 00 01 01 00 01 01 01
> 0000300 00 01 00 00 00 00 01 00 00 00 00 00 00 01 01 00
> 0000320 01 01 00 01 00 01 01 00 00 01 00 01 00 01 01 00
> 0000340 01 01 00 01 00 01 01 00 00 00 01 00 00 01 01 00
> 0000360 00 01 00 01 00 01 01 01 00 00 01 00 00 01 01 01
> 0000400 00 00 01 01 00 00 01 01 01 00 01 00 00 00 01 00
> 0000420 00 00 00 00 00 01 00 01 01 00 01 00 00 01 01 00
>
> ...
>
> I would like to be sure data has been modulated/demodulated correctly.
> Isn't there a way of opening this file as text?
>
> Thank you for your help,
> Irene
>
>
>
> [1] - http://www.wu.ece.ufl.edu/projects/softwareRadio/#Related%20Work
>
> --
> View this message in context: 
> http://www.nabble.com/Modulation-problem---tp17316660p17345229.html
> Sent from the GnuRadio mailing list archive at Nabble.com.
>
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