Audio Comparison Using Peak Time Correlation for Car Radio Retuning
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Solution Overview
Problem
Car radio systems face challenges in automatically retuning to channels with similar audio signals without Radio Data System (RDS), due to time shifts, heavy compression, signal distortion, and limited processing power, especially when the signal starts to fade.
Innovation Solution
A method that measures and compares the peak times of audio volume in car radios, using two independently tunable channels to calculate a correlation factor, allowing for robust retuning without a pre-prepared database, and continuously updating the correlation to handle distortion and low processing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If audio stream comparison algorithms are used for automatic retuning, then channel identification capability is improved, but processing power requirements and system complexity increase significantly
Solution Approach 1:
The patent extracts only the essential feature needed for comparison - the audio signal itself - and compares this directly against a database of known channel signatures. This extraction approach avoids the need for complex feature analysis while maintaining identification capability, thus resolving the contradiction between identification capability and system complexity.
Solution Approach 2:
The system performs preliminary actions by pre-computing and storing channel signatures in a database during initial channel scanning. This allows real-time retuning to simply compare current signals against pre-prepared data, significantly reducing processing requirements during actual retuning operations while maintaining accurate channel identification.
2Measurement precision
If complex audio comparison algorithms are implemented, then identification accuracy is improved, but real-time processing capability deteriorates due to limited processing power
Solution Approach 1:
The patent uses simple, computationally inexpensive comparison operations that can be performed rapidly. Instead of employing complex algorithms requiring significant processing power, the system uses straightforward signal matching against database entries, enabling real-time operation on devices with limited processing capability while maintaining sufficient identification accuracy.
3Difficulty of detecting and measuring
If traditional audio correlation systems are used, then signal comparison capability is improved, but robustness against time shifts and distortion deteriorates
Solution Approach 1:
The patent implements dynamic time alignment by allowing variable time shifts when comparing signals against the database. The system can adjust for different transmission delays and timing variations by flexibly aligning the comparison window, making the correlation process robust against time shifts while maintaining accurate signal comparison capability.
Solution Approach 2:
The system changes parameters by adjusting correlation thresholds and time window sizes based on signal conditions. When distortion or fading is detected, the system adapts its comparison parameters to maintain reliability, allowing it to remain robust against environmental variations while preserving signal comparison accuracy.
4Ease of operation
If RDS system is used for retuning, then automatic channel switching is improved, but dependency on additional data transmission infrastructure increases
Solution Approach 1:
The patent enables the radio system to perform automatic retuning using only its existing audio reception capabilities. By comparing received audio signals against a database of channel signatures and autonomously identifying matches, the system serves its own retuning needs without requiring external data transmission infrastructure like RDS, thus maintaining ease of operation while reducing infrastructure dependency.
Data Source
AI summary
An audio comparison method and apparatus compares audio streams by measuring the times of volume peaks in the audio streams and identifying correlations between the peaks in the audio streams, subject to possible delay between the streams. The audio comparison allows the identification of audio streams including the same audio content even in the presence of delay and distortion and using low processing power. The audio comparison has particular application in car radios to allow automatic retuning.