Adaptive Stereo Decorrelation Module for Analog Radio
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Solution Overview
Problem
Analog radio receivers struggle to maintain stereo reception quality during poor signal reception, as the energy of the L-R signal decreases, leading to a loss of stereo effect due to strong correlation between left and right sound signals.
Innovation Solution
A decorrelation module is employed to adjust the decorrelation rate based on the radio reception quality coefficient 'alpha', with higher decorrelation in poor reception conditions to restore the stereo effect, using elementary blocks with variable gain and delay parameters, and high-pass filtering to isolate and recreate high-frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radio reception quality is poor, then the energy of the L-R signal decreases, but the stereo effect is lost due to strong correlation between left and right sound signals
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the decorrelation coefficient based on the received signal strength indicator (RSSI). When reception quality is poor (low RSSI), the decorrelation coefficient is increased to enhance the L-R signal energy and restore the stereo effect. When reception quality is good (high RSSI), the decorrelation coefficient is decreased to maintain natural sound reproduction. This adaptive parameter adjustment resolves the contradiction between maintaining reliability under poor reception and preserving the stereo effect.
2Reliability
If the decorrelation rate is increased to restore stereo effect in poor reception, then the stereo effect is improved, but the natural sound quality may be degraded
Solution Approach 1:
The patent implements dynamics by making the decorrelation coefficient adjustable and adaptive rather than fixed. The coefficient dynamically changes based on reception conditions (RSSI levels), allowing the system to optimize between stereo effect restoration and sound quality accuracy in real-time. This dynamic adjustment resolves the contradiction by applying stronger decorrelation only when necessary (poor reception) and reducing it when reception is good, thus maintaining natural sound quality.
Solution Approach 2:
The patent changes the parameter of the decorrelation coefficient based on reception quality metrics. By adjusting this parameter adaptively, the system can restore the stereo effect when needed while minimizing degradation of natural sound quality when reception is adequate, thus resolving the contradiction between improving stereo effect and maintaining sound quality accuracy.
3Ease of manufacture
If a fixed decorrelation rate is used, then the system is simple to implement, but it cannot adapt to varying reception quality conditions
Solution Approach 1:
The patent transforms the static decorrelation rate into a dynamic parameter that adapts to varying reception conditions. By introducing adaptability through RSSI-based adjustment, the system can optimize performance across different reception quality scenarios while maintaining a relatively simple implementation structure, thus resolving the contradiction between simplicity and adaptability.
Solution Approach 2:
The patent employs parameter changes by making the decorrelation coefficient variable based on reception quality. This approach enables the system to adapt to different reception conditions without requiring a completely complex system architecture, thereby balancing ease of implementation with adaptability to varying reception quality.
Data Source
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AI summary
The invention relates essentially to a method of optimizing stereo reception for an analogue radio, characterized in that it comprises the following steps: the right sound signal (SD) and the left sound signal (SG) demodulated are applied as input to a decorrelation module (5) having a variable decorrelation rate, the decorrelation rate of the decorrelation module (5) is modified as a function of the reception quality coefficient "alpha" provided by the radio, so that the smaller the reception quality coefficient "alpha", the higher the decorrelation rate applied by the decorrelation module (5), and the larger the reception quality coefficient "alpha", the lower the decorrelation rate applied by the decorrelation module (5). The invention furthermore proposes a module for generating high-pitched sounds which makes it possible to recreate the high-frequency component (SHF) of the right or left sound signals which has been removed in the event of poor reception.