Double-Step CORDIC Processor Decision Postponing
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Solution Overview
Problem
The classical CORDIC algorithm requires a large number of iterations to achieve high accuracy, which limits computation speed, and existing double-step CORDIC methods do not significantly improve performance due to complex control logic and magnitude comparisons.
Innovation Solution
The double-step CORDIC processor with decision postponing, which combines two classical CORDIC iterations into a single stage and postpones the decision-making process to the next stage, reducing computational delay and increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the classical CORDIC algorithm performs a large number of iterations to achieve high accuracy, then measurement precision is improved, but speed deteriorates
Solution Approach 1:
The patent merges two classical CORDIC iterations into a single double-step iteration by combining the rotation operations and control logic. This reduces the total number of iterations required while maintaining the same level of accuracy, thereby improving computation speed without sacrificing precision.
Solution Approach 2:
The patent performs preliminary computations by pre-computing and storing rotation angles in a look-up table. This allows the main computation to proceed faster by avoiding repeated trigonometric calculations, thus improving speed while maintaining accuracy through pre-prepared data.
2Speed
If the double-step CORDIC method combines two classical CORDIC iterations into a single step, then speed is improved, but device complexity increases due to complex control logic
Solution Approach 1:
The patent performs preliminary computations by pre-computing and storing rotation angles in a look-up table. This allows the main computation to proceed faster by avoiding repeated trigonometric calculations, thus improving speed without requiring complex real-time control logic.
Solution Approach 2:
The patent uses a look-up table to store pre-computed rotation angles, effectively copying the results of complex trigonometric calculations into a simple data structure. This replaces complex control logic with simple table access, reducing device complexity while maintaining high speed.
3Measurement precision
If the double-step CORDIC method uses magnitude comparisons for control decisions, then accuracy is maintained, but speed deteriorates due to full word-length additions/subtractions
Solution Approach 1:
The patent performs preliminary computations by pre-computing and storing rotation angles in a look-up table. This eliminates the need for full word-length additions/subtractions during the main computation, maintaining accuracy while significantly improving speed.
Solution Approach 2:
The patent extracts the complex control decision logic from the main computation by using pre-computed lookup tables. This separates the accuracy-maintaining function (table lookup) from the speed-critical function (simple arithmetic operations), allowing both requirements to be satisfied simultaneously.
Data Source
AI summary
A double-step CORDIC algorithm is implemented for conventional signed arithmetic using multiple iteration stages in which at least one stage implements decision postponing, in which the decision for each stage is delayed until the next stage. In one implementation, the decision for the previous stage is implemented in parallel with the execution of CORDIC equation functions for the current stage. Implementing the double-step CORDIC with decision postponing algorithm can increase the speed of the CORDIC function compared to prior-art CORDIC implementations.