Digital Radio Audio Blend Buffering for Signal Quality
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Solution Overview
Problem
Existing digital radio broadcast receivers face challenges in smoothly blending digital and analog signals, leading to unpleasant disruptions in the listening experience due to limitations in the blending function, such as squawk-like interference and increased memory requirements for buffering audio packets.
Innovation Solution
A digital radio receiver apparatus that buffers compressed audio packets in an input buffer and computes estimated digital audio quality indicators to guide the blending of analog and digital signals, allowing for a smaller input audio blend buffer and preventing repetitive blending between low and high bandwidth signals by using advance knowledge of signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blending function is used to transition between analog and digital signals, then the audio output can maintain continuity, but the blending transitions can degrade the listening experience due to signal quality differences and create squawk-like interference
Solution Approach 1:
The patent buffers compressed audio packets in advance before decoding, allowing the system to predict future audio quality. This preliminary buffering enables the blending function to anticipate signal degradation and prepare for smooth transitions, preventing squawk-like interference by having ready-to-use audio packets from the buffer when signal quality deteriorates.
2Reliability
If large audio packets buffers are used to smooth the blending function, then blending transitions become smoother, but cost and on-chip memory requirements increase
Solution Approach 1:
The patent buffers compressed audio packets (before decoding) rather than decoded audio packets. Since compressed packets occupy less memory space than fully decoded audio data, this preliminary buffering approach achieves the same blending smoothness with significantly reduced memory requirements, lowering cost and on-chip memory usage.
3Device complexity
If the blending frequency is reduced using computed estimated signal-to-noise values, then the complexity of blending management is reduced, but the accuracy is limited under certain conditions such as interference or selective fading
Solution Approach 1:
The patent computes estimated audio quality indicators from buffered compressed audio packets in advance, before the actual blending decision is needed. This preliminary quality assessment provides more accurate predictions of future audio quality, especially under challenging conditions like interference or selective fading, enabling better blending decisions without increasing operational complexity.
Data Source
AI summary
A method and apparatus are provided for blending analog and digital portions of a composite digital radio broadcast signal by processing compressed audio packets to compute corresponding digital audio quality indicator values, storing the compressed audio packets in an audio blend buffer, processing audio information from each compressed audio packet stored in the audio blend buffer with an audio decoder to generate decompressed digital audio signal samples, and using the digital audio quality indicator values to guide a blending process for combining analog audio signal samples with the digital audio signal samples to produce an audio output by preventing unnecessary blending back and forth between analog and digital if the digital audio quality indicator values indicate that the compressed audio packets are degraded or impaired.