title: FIR filter (implementation )
body: <p>I want to make a FIR filter. I have an array of coefficients (buffer[size]) and an array of data (filter[size_filter]). I have to do a convolution between the two arrays:</p>
  
  <pre><code>for(j = 0;j &lt; size+size_filter;j++)
  {
    output[j] = 0;
    for(i = 0;i &lt; size_filter;i++)
    {         
      output[j] += buffer[i]*filter[j-i];
    }
  }
  </code></pre>
  
  <p>output[size+size_filter] is the result. Where I'm wrong?</p>