Multi-Rate Audio Codec Mixing With Low-Latency Up-Sampling
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Solution Overview
Problem
Conventional audio processing systems face challenges in efficiently handling multi-rate audio signals from various sources, particularly in wireless devices, where they need to support duplex operations and accommodate new audio compression techniques and formats, requiring advanced codec devices with flexible and efficient processing capabilities.
Innovation Solution
A system and method for processing multi-rate audio signals using an audio coder/decoder (codec) that up-samples multiple audio signals to a common data sampling rate, employing FIR or IIR filters for equalization, multiple half-band interpolation operations, and dynamic gain adjustment, with the ability to mix and down-sample signals for communication to output devices like Bluetooth radios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple audio signals with different sampling rates are processed using conventional methods, then the system can handle basic audio playback, but the processing efficiency deteriorates and noise effects increase
Solution Approach 1:
The patent changes the sampling rate parameter of audio signals by employing up-sampling techniques where multiple audio signals with different sampling rates are converted to a common higher sampling rate. This parameter transformation enables efficient parallel processing while reducing noise artifacts that occur in conventional down-sampling or separate processing methods.
Solution Approach 2:
The audio processing system is designed to universally handle multiple audio signals with varying sampling rates through a unified up-sampling architecture. The system can process different audio sources (microphone, media player, Bluetooth) simultaneously by converting them all to a common sampling rate, providing multi-functional capability while maintaining processing efficiency.
2Adaptability or versatility
If the system supports duplex operations with multiple audio sources, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The audio processing system is segmented into distinct functional modules: up-sampling modules for each audio source, a mixing module, and an output module. Each audio source (microphone, media player, Bluetooth) has its own processing path that is segmented and independently managed, reducing overall system complexity while maintaining high adaptability.
Solution Approach 2:
The patent introduces an intermediary up-sampling and mixing stage that mediates between multiple audio sources with different sampling rates and the final output. This intermediary processing layer simplifies the complexity by providing a standardized interface that handles rate conversion and mixing, allowing the system to support multiple sources without proportionally increasing complexity.
3Manufacturing precision
If audio signals are up-sampled to a common rate with multiple filtering operations, then the manufacturing precision of audio quality improves, but the processing time increases
Solution Approach 1:
The up-sampling process employs periodic filtering operations where filters are applied at regular intervals during the up-sampling process. This periodic action maintains high audio signal quality through proper filtering while managing processing time by not applying filters continuously but rather at structured intervals appropriate for the up-sampling ratio.
Solution Approach 2:
The system performs preliminary up-sampling and filtering operations on each audio signal before mixing them together. By preparing the signals in advance with appropriate filtering to ensure quality, the subsequent mixing and output stages can proceed more quickly, overall managing the processing time while maintaining manufacturing precision of audio quality.
Data Source
AI summary
An audio codec in a wireless device may be utilized for up sampling two or more audio signals to a same data sampling rate. Each audio signal, such as digital audio, voice, and polyringer, for example, may be received at one of a plurality of data sampling rates. Audio signals may be equalized and/or compensated with an FIR filter before up sampling or with an IIR filter to reduce overall processing latency. Multiple half-band interpolation operations may perform the up sampling. The first half-band filter may be replaced by an IIR filter to reduce overall processing latency. A gain of the up-sampled data may be adjusted to reduce noise effects. The channels of the up-sampled audio signals may be mixed and later further up sampled for subsequent communication to an output device. The up-sampled mixed audio signals may be down sampled for communication to a Bluetooth radio.