DSP Tools

[aplnx]

   Hello friends,

I'm using System Generator/Simulink to build a communication system that uses reed-solomon encoder. First, I created a setup that enable me to check the output data. I have noted that the input data are the same as the output data with a delay of four samples. Somebody could explain what is going wrong?

   Thanks.

Cláudio F. Dias

[eilert]

Hi claudio.

what makes you think that something is wrong?

RS-encoded symbols are appended to the end of a data block.

So in the beginning you see your data coming out of the encoder.

How long have you simulated(how many clock ticks), and what block size did you choose?

Some more details about your design and testbench would be helpful.

Have a nice simulation

  Eilert

[aplnx]

Hello Eilert,

    Thanks for your reply. I advanced a bit more since the last post. So, I will give you some information to turn the things clear.

Well, I am trying to use the custom code k=239 n=255 with the 8-bit symbol width. I've understood that I need feed the input of the RS coder with 239 symbols and complete another 16 spaces with zeros to totalize 255 symbols. The coder deliver in the output the same 239 symbols and 16 symbols of coded data.

I didn't know about this. I thought it was just put the symbols in the encoder and it would make the rest of the work.

I've been overcome this problem. I created a set of simulink models and m-code that test the code. I created a model for transmit ('TX.mdl'), receiver ('RX.mdl') and a channel ('CHANNEL.mdl'). The transmitter and receiver models have coder/decoder System Generator Blocks. The channel only have native simulink blocks. This model apply BPSK modulation passing the data through a AWGN channel.

Now, I am testing the code with a high Eb_N0 ratio. I don't receiving all data correctly as expected. I'm working on it, but I don't know what is happening yet.

I attached my files in this post. If you want to see that happens run mainControl.m.