How to increase the range of Cordic processor

[amehtaac]

I read that adding two '0' iterations can increase the range of Cordic from 45 to 180 degrees. Can anyone tell me what these '0' iteration means?
Does that mean instead of 45 as the initial angle, we will now consider 180 to be the initial angle.

 

[FvM]

Telling where you read this can help to get answers. Isn't standard Cordic range larger than 45°, e.g. +/- 90°?

 

[amehtaac]

"FPGA Implementation of a Novel Type DDS Based on CORDIC Algorithm, J.-M. Huang, Z. Chen, H. Guo, and K. Han". This is where I read.

 

[amehtaac]

Telling where you read this can help to get answers. Isn't standard Cordic range larger than 45°, e.g. +/- 90°?

Yeah, I am sorry, the range is around 90. The initial angle is 45.

 

[psoc77]

I believe that by two 0-iterations assumed bringing any angle from 0-360deg into 0-90deg sector, based on sine syandard simmetry properties:
sine(-x)=-sine(x) and
sine(90-x)=sine(x).
So using two steps one can converf any angle into 0-90deg sector and then proceed with CORDIC iterations.