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Altera_Forum
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16 years ago

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Hi all, Im trying to implement an arctan function in Quartus II using a Chebyshev approximation algorithm. The problem is that it only accepts numbers between -1 and 1 as arguments(including fr...
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Altera_Forum
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16 years ago

How many bits are you are using for I and Q channels? How many are for fractional and integer parts?

Which are maximum and minimum values for I and Q channels?.

However, if the I Q channels bit size (N) don't grow, you should be able to use the arctan core without problems assuming a signed fixed point format b_N-1. b_N-2 ... b_0, any scale value is canceled after doing Q/I.

Be careful with divider circuit, because it can introduce overflows.

Fixed point division is performed correctly by doing

(Q<<Nf)/I

Where Nf is the fractional bits size.