# Re: pccc encoder

**URL:** <https://www.ruby-forum.com/t/re-pccc-encoder/241471>\
**Category:** GNU Radio\
**Created:** [April 8, 2015, 6:20pm UTC](https://www.ruby-forum.com/t/re-pccc-encoder/241471 "2015-04-08T18:20:46Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [April 8, 2015, 6:20pm UTC](https://www.ruby-forum.com/t/re-pccc-encoder/241471/1 "2015-04-08T18:20:46Z")

</div>

Since your constellation is complex, then its dimensionality (in the  
chunks\_to\_symbos block, as well as in the PCCC decoder block)  
should be set to 1 (you are now have it at 2).

The convention is that the chunks\_to\_symbols array is arranged as

a11, a12, … a1d, a21 a22,…,a2d,… aM1, aM2, …aMd

so that it is to be understood as the 2 D array

a11, a12, … a1d,  
a21 a22,…,a2d,  
…  
aM1, aM2, …aMd

with dimensionality d.  
Then, at each instance, it outputs the “row” that is indexed by the  
input  
symbol.

Achilleas

PS: I also suggest you make a variable “constellation” and put in there  
your constellation and then input it in both  
the chunks\_to\_symbols AND the PCCC decoder block so that you are sure  
you  
are consistent.

---

<div class="post-metadata">

**Author:** ![Achilleas\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/74df32/32.png) [@Achilleas\_A](https://www.ruby-forum.com/u/Achilleas_A)\
**Post date:** [April 11, 2015, 8:53pm UTC](https://www.ruby-forum.com/t/re-pccc-encoder/241471/2 "2015-04-11T20:53:05Z")

</div>

Hi

Thank you for your help.

Now i`m trying to use only the pccc encoder and pccc decoder blocks, without modulation. I`m using the awgn1o2\_8.fsm for the fsm parameter because i need a state  
machine with those characteristics, and i`m using the error rate block to make sure that the source is the same than the output of the decoder. But this value is in the range between 0.02 and 0.06 (when the source is a random source) when it should be 0 (i`m not using any noise or channel  
blocks) and is 0.02 with the vector source V = (0, 1, 0,1,1,0,0,1). Does  
the  
blocks itself introduce an error?

Also i would want to know if i can create my own fsm file in the case i  
need a state machine with characteristics I=2, S=64,O=8 (There is any in  
the  
fsm\_files folder). I created one but i don`t know either which is the  
format  
i should use nor where to save it.  
How the Bits per Symbol parameter influences in the error rate?

Again i apologize for my english.

Thank you very much for your help.  
FSM284\_Vector\_Cod\_decod\_turbo\_error\_rate.grc  
[http://gnuradio.4.n7.nabble.com/file/n53264/FSM284\_Vector\_Cod\_decod\_turbo\_error\_rate.grc](http://gnuradio.4.n7.nabble.com/file/n53264/FSM284_Vector_Cod_decod_turbo_error_rate.grc)

–  
View this message in context:  
[http://gnuradio.4.n7.nabble.com/pccc-encoder-tp53173p53264.html](http://gnuradio.4.n7.nabble.com/pccc-encoder-tp53173p53264.html)  
Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com).