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AR# 40407

CORDIC - Outputs from core are different from Matlab solutions

Description

I am using the CORDIC core to implement an arctan function in my design. 

I am noticing however, that at near-zero values of X inputs, the result from CORDIC varies considerably from the output of calculating arctan through Matlab.

Why is there a difference in the output and how can I resolve the error?

Solution

The difference in output is due to an output quantization error introduced by the digital nature of the core.

Details on this subject can be found in the CORDIC datasheet, under the section Output Quantization Error.

The datasheet suggests that the output of the core might be more accurate if the bit magnitude of the input vectors is increased.  


AR# 40407
Date Created 02/01/2011
Last Updated 12/03/2014
Status Active
Type General Article
IP
  • CORDIC