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Altera_Forum's avatar
Altera_Forum
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14 years ago

NCO help...

Hi i'm trying to test a fixed point filter on a FPGA board, my filter has an input of 16 bit, but the maximum value it can take without saturation is 1023 which is 11 bits. so far the only signal i'v...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

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If you are working on schematics then just connect MSB of NCO to all remaing MSBs of filter input.

if you want VHDL then:

sine16 = std_logic_vector(resize(signed(sine11),16));

You can also keep your NCO on 16 bits then select its 11 MSBs instead of setting it to 11 bits., your choice ...

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Wouldnt this give me a width mismatch? because i'm not sure exactly how i would do this can i get an example...i'm talking about schematic way.