Delay-Locked Loop Code Phase Estimation Using Replica Signal Segmentation
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Solution Overview
Problem
Conventional delay-locked loop (DLL) circuits are unable to precisely estimate the code phase delay of spread spectrum code signals due to limitations in circuitry and external environments.
Innovation Solution
An apparatus comprising a spread spectrum code generating circuit, a calculating circuit, and an adjusting circuit that generates replica spread spectrum signals with different phases, calculates error statistics, and adjusts the estimated code phase delay based on phase differences between sample points and signal transition points to achieve precise estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional delay-locked loop circuit is used, then device complexity is reduced, but measurement precision of code phase delay deteriorates
Solution Approach 1:
The patent segments the code phase delay estimation process into multiple independent components: a correlation calculation unit that processes multiple replica signals simultaneously, and a phase difference calculation unit that separately computes phase differences between sample points and transition points. This segmentation allows each component to perform its specific function with optimized complexity, achieving high measurement precision without requiring a single overly complex circuit.
Solution Approach 2:
The patent introduces an intermediary calculation process that computes phase differences between sample points and signal transition points as an intermediate step. This intermediary phase difference information is then fed back to adjust the estimated code phase delay, serving as a mediator that refines the measurement precision without directly increasing the overall circuit complexity by providing a computational refinement layer.
2Measurement precision
If more replica spread spectrum signals are generated for better estimation, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges the processing of multiple replica spread spectrum signals into a unified correlation calculation unit that handles all replica signals simultaneously. By combining the computation of multiple signals in a single integrated unit rather than processing them through separate independent circuits, the system achieves improved measurement precision through multi-signal analysis while avoiding the linear increase in device complexity that would result from duplicate processing paths.
Solution Approach 2:
The correlation calculation unit is designed with multi-functionality, serving both to generate the replica spread spectrum signals and to calculate the correlation values for phase estimation. This universal processing unit performs multiple functions within a single circuit structure, allowing the system to handle multiple replica signals for enhanced measurement precision without proportionally increasing device complexity.
3Measurement precision
If phase difference calibration is performed using sample points and transition points, then measurement precision improves, but calculation time increases
Solution Approach 1:
The patent performs preliminary identification and characterization of signal transition points before the final phase difference calculation. By pre-processing the signal to mark transition point locations and prepare the correlation data from multiple replica signals in advance, the system reduces the computational burden during the final phase difference calculation step, thereby improving measurement precision through comprehensive calibration while minimizing the overall calculation time.
Data Source
AI summary
A method for performing delay locked looping upon a received signal which reduces the asymmetry of auto-correlation function resulting from sampling is provided. The received signal is a spread spectrum code signal, and the method includes: generating a plurality of replica spread spectrum code signals according to an estimated code phase delay and phase spacing, the replica spread spectrum code signals having phases respectively different from the phase of the received signal; calculating a spread spectrum code error statistics signal according to the replica spread spectrum code signals and the received signal; and adjusting the estimated code phase delay according to the spread spectrum code error statistics signal and a phase difference between a sampled point of at least one replica spread spectrum code signal and a corresponding signal transition point.