Good Evening, I am a student of eletronic engineer in Brazil and I am using GNURadio Companion as a research. I have attached some pictures of my model on GRC and the problems. In this case, I made a circuit with PSK modulation, using the block Chunks to Symbol. Before and after the the Channel Model, I used the root raised cosine filter to get a better signal of FFT at the WX GUI FFT Sink. Using the software called octave I could measure the power at the output of filters, First I read the file saved from the block file sink and after I could measure the power using the equation. mean(abs(in).^2). After this process i could see that the power at the output of Chuns to Symbol was equal the number 1 and in the output of the first filter was very small number, different of 1 and the factor that made this happen was the interpolation factor in the properties of the root raised cosine filter. I couldn't find a relation of the interpolation factor of the filter to get the number of power equal the value at the output of Chunks to symbol. After some tests i get a result equal the number 1 in the output of the two filters, but with a value very big of noise the system measured a value of BER equal zero and the constellation was very clear. When I use this values of the model attached I can find results very near of the theorical values from the curve Eb/N0 plotted at matlab, but some samples are different of the theorical value. My doubt is, how can I do to make the BER equal the value theorical( from the curve of EB/N0 of the modulation)and get a good FFT signal ?

**Problem in simulation on GRC at the measure of BER in digital modulations with Chunks to Symbol in r**

on 2014-05-14 05:26