Complex Signal Phase Estimation Without Lookup Tables
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Solution Overview
Problem
Existing phase shift key (PSK) and frequency shift key (FSK) demodulators face challenges with complex hardware, vulnerability to frequency offsets, and high memory requirements due to complex phase determination techniques, especially those using lookup tables.
Innovation Solution
A method using Taylor polynomials to estimate the phase of complex signals by determining quadrant-specific signs and bias values for in-phase and quadrature-phase components, reducing hardware complexity and avoiding discontinuities in phase approximation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lookup tables are used for phase determination, then phase estimation accuracy is improved, but memory space requirements increase
Solution Approach 1:
The patent extracts only the essential components needed for phase determination by using a simplified calculation based on in-phase and quadrature components with sign determination and bias addition, eliminating the need for large lookup tables while retaining adequate phase estimation accuracy
Solution Approach 2:
Instead of using lookup tables to find phase values from pre-computed data, the patent inverts the approach by directly calculating phase values through a simplified mathematical relationship involving sign determination and bias addition, thereby reducing memory requirements
2Measurement precision
If complex phase determination techniques are used, then phase estimation accuracy is improved, but hardware complexity increases
Solution Approach 1:
The patent extracts and retains only the critical elements for phase determination (in-phase component, quadrature component, sign determination, and bias addition), removing complex computational requirements while maintaining sufficient accuracy for demodulation applications
Solution Approach 2:
The patent employs simpler computational operations that require less hardware resources, using basic arithmetic operations and sign determination instead of complex algorithms, thereby reducing hardware complexity while achieving acceptable phase estimation
3Productivity
If conventional phase determination methods are used, then phase values can be obtained, but vulnerability to frequency offsets increases
Solution Approach 1:
The patent changes the approach to phase determination by using a method that is less sensitive to frequency variations, employing sign determination and bias addition that maintains reliability under frequency offset conditions compared to conventional methods
Data Source
AI summary
A method of generating a phase value representative of a phase of a complex signal that includes an in-phase component and a quadrature-phase component includes determining a first sign for a first value and a second sign for a second value based on a quadrant occupied by the complex signal. The in-phase component is multiplied by the first value with the first sign, thereby generating a first multiplication result. The quadrature-phase component is multiplied by the second value with the second sign, thereby generating a second multiplication result. The first multiplication result, the second multiplication result, and a bias value are added, thereby generating the phase value for the complex signal.