Bidirectional Chirp Signal Generation Using Phase Accumulation Polynomial
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current synthetic aperture radar systems face challenges in generating high-quality bidirectional chirp signals due to phase accumulation errors and increased memory requirements, especially at high bandwidths, which affect signal quality and increase costs.
Innovation Solution
An apparatus and method utilizing a polynomial processor to generate a bidirectional chirp signal by extracting time spacing information and applying a phase accumulation polynomial, replacing the traditional phase accumulator to minimize phase errors and maintain signal linearity, while using a direct digital synthesizer (DDS) with a multiplexer to generate out-of-phase signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a phase accumulator is used to generate chirp signals, then the signal generation is simple, but phase accumulation errors occur at high frequencies
Solution Approach 1:
The patent changes the mathematical model from linear phase accumulation to polynomial phase accumulation. By using a polynomial function that models the ideal chirp signal phase directly, the system achieves high phase accuracy without the accumulation errors that plague linear methods at high frequencies.
Solution Approach 2:
The patent replaces the mechanical accumulation process (adding phase values step-by-step) with a direct polynomial calculation. This substitution eliminates the compounding errors inherent in iterative accumulation by computing each phase value independently based on the ideal chirp model.
2Manufacturing precision
If memory map scheme is used to store ideal waveforms, then signal quality is maintained, but memory size and switching time increase with bandwidth
Solution Approach 1:
The patent extracts only the essential parameters needed to generate the chirp signal (polynomial coefficients representing frequency, chirp rate, and phase) rather than storing complete waveform data. This reduces memory requirements from storing entire waveforms to storing compact parameter sets.
Solution Approach 2:
Instead of storing actual waveform data, the patent stores a mathematical model (polynomial coefficients) that can generate the waveform on-demand. This creates a compact representation that reproduces the ideal signal without requiring large memory storage.
3Quantity of substance
If DDS is used to generate chirp signals, then memory usage is reduced and switching speed increases, but quantization and phase truncation errors occur
Solution Approach 1:
The patent changes the phase calculation from quantized discrete steps to continuous polynomial evaluation. By using polynomial functions with sufficient precision arithmetic, the system maintains waveform accuracy while still benefiting from DDS's low memory requirements and fast switching capability.
4Device complexity
If bidirectional chirp signals are generated with fixed start phase, then generation is simplified, but phase matching errors occur between up-chirp and down-chirp signals
Solution Approach 1:
The patent makes the phase calculation dynamic and direction-aware by incorporating the chirp direction (up or down) into the polynomial evaluation. The polynomial model naturally adapts to generate correct phase relationships for both up-chirp and down-chirp signals, eliminating fixed-phase limitations.
Data Source
AI summary
The present invention relates to an apparatus and method for generating a bidirectional chirp signal by using a phase accumulation polynomial, and the apparatus for generating a bidirectional chirp signal according to an embodiment may include an extraction unit extracting time interval information from the output of a frequency accumulator, a polynomial handling unit applying the phase accumulation polynomial to the extracted time interval information to generate a polynomial output value, and a bidirectional chirp signal output unit outputting a bidirectional chirp signal on the basis of the generated polynomial output value.