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Altera_Forum's avatar
Altera_Forum
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15 years ago

How can i use CORDIC ?

Hello i am trying to use the cordic core { http://opencores.org/project,cordic } with no sucess. Say i have a complex number of 4 + 5i. I have inserted 1000 as the Xi input and 1001 as the Yi...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

the outputs are 20 bits, 16 bits integer and 4 bits fraction so:

magnitude of 103 (67 in hex) means 6.7

and Angle of 146811 (23d7b) i.e 23d7.b degrees = 9175 and this wraps 25 times to 175 degrees.

your figure of .8961 is in rads I believe so becomes .8961 * 180/pi = 51 degrees.

So at least magnitude seems working.

The angle may not actually have been meant to be wrapped up, it then does not need 16 bits for integer part (range is 0 to 360) i.e. only 9 bits may represent it and the rest 11 bits as fraction hence A = 146811/2^11 = 72 degrees which I think is a bit better than 175 !!!

The documentation is poor or the code does not work I am afraid.