HI Danny, Thank you very much for your answer. It helped me a lot. but i'm still have some problems. when i use the real part of the complex output of the dec_fir block, i get an overall bandwidth reduction of 8x without problem. the problem is when i use the real and imaginary parts for an overall bandwidth reduction of 4, i see two tones instead of one, so i get a reduction of bandwidth but i can't get rid of this extra tone. so i can't have a reduction of 4x on my bandwidth, how can i overcome this problem?
thanks in advance. regards. 2014-06-03 13:13 GMT-04:00 Danny Price <[email protected]>: > Hi Edgardo > > If you're after a decimating FIR filter, then you can use the mixer and > dec_fir. > > Here's a screenshot showing a design that selects 200 MHz bandwidth out of > 400 MHz; that is, 4 parallel real-valued --> 1 complex-valued stream: > https://dl.dropboxusercontent.com/u/9870263/dec-fir.png > > Note that the dec_fir is a little picky about the length of your filter > (eg 100 vs 101 taps). I just used the fdatool for the coefficients (sounds > like you're already familiar with this). > > Using this, you could convert your 8 parallel real inputs to 1 complex > output, for an overall bandwidth reduction of 4x. > > Regards > Danny > > Edgardo Antonio <[email protected]> > June 3, 2014 at 12:27 PM > Hi everybody. > > I have a problem building a digital filter before the data enter to the > PFB on my design. I need to design an FIR band pass filter but i don know > if there is a well known way to do this (maybe there is a block > pre-designed). > > i found a FIR compiler on the xilinx blockset and i load the fir > coefficients from the fda tool without problems. I Have 8 samples in > parallel coming from the ADC each clock FPGA clock cicle. > > it seems to me the problem is that the xilinx FIR compiler is filtering > each path independently, in other words not considering the 8 inputs in > parallel like 8 samples of a signal each taken at the same rate sample. > > i hope some one understand the problem and could have a solution. > > Have anyone has the same problem? Thank you > -- > *Edgardo Huaracán Durán* > > > *Memorista Observatorio Astronómico Nacional* > > *Universidad de Chile* > > -- *Edgardo Huaracán Durán* *Memorista Observatorio Astronómico Nacional* *Universidad de Chile*
