Re: [oc] Query on cordic...

[Richard Herveille <richard@asics.ws>]

How hard can it be ????
Please think first speak later, or better read the documentation it says 
how to do so.
Just in case you don't have an internet connection:


Write a pre- and postfunction:
1) The pre-function has to check in which quadrant your rotation point is
    is (simply check the angle)

2) Transfer the rotation-point back into the first quadrant

cordic:
3) Store the quadrant information and delay it (same delay as
    cordic-algorithm)

4) Feed the pre-processed data into the cordic

post-function:
5) Use the stored quadrant information to modify the results

Richard



>I am working on cordic currently.
>I need to rotate the incoming samples by some theta.
>the range of theta may be from -60 to +60.
>I want to use the cordic to do the rotation.
>But the problem is my theta will increase linearly.
>some thing like this:
>if starting theta is 20 degrees. then next thetas are
>40,60,80,100,120,140,160, 180, 190, 200, ......, 380,
>400, 420, ........900, 920 .............
>goes on.
>some of you know that the limitation of Cordic is the
>input angle should be between -90 and +90.
>Can some body suggest me some method to do this type
>of rotation?
>of course rotation with 40 degrees is same as rotating
>with 400 degrees or 760 degrees or 1120 etc due to
>periodicity.
>Any help in this regard is appreciated.
>
>Regards,
>Sridhar

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