Tuesday, 12 June 2012

DATV Express Spectrum

As promised here is a picture of the DATV Express output spectrum.
I have averaging switched on, on the Spectrum Analyser. The Express
board is operating at 20 MSamples per second and the filter in the
FPGA interpolates X4 and is a 49 tap root raised cosine filter with
x/sin(x) compensation. The DAC is a 14 bit DAC and I am using
67% of the hardware multipliers to implement the filter (24/36).
The filter is pipelined and is non blocking. I am a novice FPGA
programmer so naturally I am very pleased with the results.

There are some issues with the output but they are hardware issues
and will be fixed in the next set of PCBs.

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