Re: [Discuss-gnuradio] need help for digital.constellation_decoder_cb in release 3.5.0

[Ben Reynwar]

On Thu, Mar 8, 2012 at 8:19 PM, Arturo Rinaldi <address@hidden> wrote:
> Nella citazione in data ven 09 dic 2011 05:55:57 CET, Ben Reynwar ha
> scritto:
>
>> On Thu, Dec 8, 2011 at 5:33 PM, Arturo Rinaldi<address@hidden>
>>  wrote:
>>>
>>> I noticed dramatic changes in the 3.5.0 release in the generation of the
>>> constellation points of digital modulations. So, if the easy part is to
>>> again modify the source code to match my needs, i need some help in using
>>> the new block :
>>>
>>> digital.constellation_decoder_cb(arg1)
>>>
>>> instead of
>>>
>>> gr.constellation_decoder(arg1,arg2)
>>>
>>> I usually used the last one where arg1 is a list containing the complex
>>> values of a generic digital modulation and arg2 is the symbol mapping
>>> (Gray
>>> Coding for instance). Which blocks do i need to put together to get the
>>> same
>>> result ?
>>>
>>> Regards, Arturo
>>>
>>> _______________________________________________
>>> Discuss-gnuradio mailing list
>>> address@hidden
>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>
>>
>> Simplest solution is probably:
>>
>> constell = digital.digital_constellation(list_of_complex_points, [], 1, 1)
>> decoder = digital.constellation_decoder_cb(constell)
>>
>> To get the symbol mapping you want, just choose the appropriate order
>> of the complex points in the list.
>>
>> The 2nd, 3rd and 4th arguments to the constellation constructor while
>> not relevant to this example are:
>>  - a mapping to be applied before differential encoding.
>>  - the rotational-symmetry of the constellation
>>  - the dimensionality of the constellation (i.e. number of complex
>> points that together map to one symbol)
>>
>> Functions to simplify the creation of commonly used constellations can
>> be found in digital.bpsk, digital.qpsk, digital.psk, and digital.qam.
>>
>> Ben
>>
>
> i made some progress in simplyfing the creation of the constellations but i
> still need help in the decoding  part.
>
> I'm trying to calculate the modulation BER by using this flow graph :
>
> http://imageshack.us/photo/my-images/819/bersimgrchomeartynetscr.png/
>
> i removed all the unnecessary parameters to my study (excess bw ,
> differential coding etc.) because i need only gray coding. and the decoding
> part is this one
>
> http://pastebin.com/wADRx7Hj
>
> could you please help me ? the grc blocks are made by invoking only the
> psk_new.py source
>
> http://pastebin.com/kawSfuPg
>
> modified by me. please help me. thx in advance
>
> Regards, Arturo.

I'd be happy to help but I'm not quite sure what exactly your
problem/question is.

Maybe you could post the python generated by grc, along with the issue
you're having?