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OFDM Implementation (DVB_T)

Started by davefowler1987 November 23, 2008
Hello All

I am looking to implement an OFDM system in VHDL on a DVB-T system. I have
designed a 16-QAM block with outputs of a 3 bit binary bus for I and Q. I
know want to build the OFDM block. 

I am looking as how to convert I and Q into a complex number I+jQ so I can
buffer that up to push through the IFFT. This willl then output an OFDM
value for I(OFDM) and Q(OFDM). 

Can anyone offer me any advice. If you need any other information please
do no hesistate to contact me.

Kindest Regards

Dave Fowler


On Nov 24, 8:41&#2013266080;am, "davefowler1987" <davefowler1...@hotmail.com>
wrote:
> Hello All > > I am looking to implement an OFDM system in VHDL on a DVB-T system. I have > designed a 16-QAM block with outputs of a 3 bit binary bus for I and Q. I > know want to build the OFDM block. > > I am looking as how to convert I and Q into a complex number I+jQ so I can > buffer that up to push through the IFFT. This willl then output an OFDM > value for I(OFDM) and Q(OFDM). > > Can anyone offer me any advice. If you need any other information please > do no hesistate to contact me. > > Kindest Regards > > Dave Fowler
What is the required format of the complex input data for the IFFT in your design? The FFT cores I have experience with (mainly Xilinx FPGA IP) have separate real (I) and imaginary (Q) inputs... so in that case there is nothing for you to do - just connect your I and Q buses to the corresponding (I)FFT inputs. (By the way, probably your data (both I and Q) should be in 2's complement format). Other than that, I am not quite sure what the question is you are asking. -T