Digital Radio Audio Path Alignment Using Decimated Offset Estimation
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Solution Overview
Problem
Existing methods for time alignment between analog and digital pathways in digital radio receivers require a large number of multiply operations and significant memory, making them inefficient in terms of accuracy and resource usage.
Innovation Solution
A method involving decimation and multiple estimations of offset values between downsampled audio streams to achieve precise time alignment, reducing the number of multiplies and memory required by iteratively shifting and correlating the streams until a desired accuracy is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional time alignment methods are used between analog and digital pathways, then time alignment accuracy is achieved, but computational complexity and memory requirements increase significantly
Solution Approach 1:
The patent segments the time alignment process into multiple stages: initial rough alignment using a coarse search method, followed by fine alignment using a refined search method. This segmentation allows the system to achieve high precision without requiring computationally expensive single-stage processing, thereby resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent performs preliminary coarse alignment before executing the computationally intensive fine alignment process. By pre-positioning the alignment point within a narrower range through the initial coarse search, the subsequent fine alignment requires fewer computational operations, thus reducing overall computational complexity while maintaining high time alignment accuracy
2Measurement precision
If traditional time alignment methods are used between analog and digital pathways, then time alignment accuracy is achieved, but memory requirements increase significantly
Solution Approach 1:
The patent divides the alignment search into coarse and fine stages, where each stage processes a limited window of samples rather than the entire signal duration. This segmentation dramatically reduces the memory buffer requirements while still achieving accurate time alignment through the progressive refinement process
Solution Approach 2:
The patent applies partial action by performing coarse alignment over a wide range with limited memory, then focusing computational resources on a narrower range for fine alignment. This approach achieves full alignment accuracy without requiring memory proportional to the entire possible offset range, thus resolving the contradiction between measurement precision and quantity of substance
3Productivity
If decimation and multiple estimations are used for time alignment, then computational load is reduced, but processing time increases
Solution Approach 1:
The patent implements periodic action through its two-stage alignment process: a rapid coarse search phase followed by a more precise fine search phase. This periodic structure allows the system to quickly eliminate large offsets in the first phase, then concentrate computational effort on smaller adjustments in the second phase, achieving both computational efficiency and acceptable processing time
Data Source
AI summary
A method for processing a radio signal includes producing first and second streams of audio samples; decimating the first and second streams of audio samples to produce first and second streams of decimated streams of audio samples; estimating a first offset value between corresponding samples in the first and second streams of decimated streams of audio samples; shifting one of the first and second streams of audio samples by a first shift value; decimating the first and second streams of audio samples to produce third and fourth streams of decimated audio samples; estimating a second offset value; determining a final offset value based on an intersection of ranges of valid results of the first and second offset values; and shifting one of the first and second streams of audio samples by the final offset value to align the first and second streams of audio samples.