Digital Audio Offset Compensation for Click-and-Pop Suppression
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Solution Overview
Problem
Digital audio devices suffer from audible artifacts like click-and-pop due to transient voltage offsets during operational mode transitions, and they also face high power consumption issues, which affect battery life and user experience.
Innovation Solution
The solution involves adding a digital offset to the digitized audio signal based on the output offset introduced by analog components, which is then processed to cancel out the systematic DC offset, thereby reducing or eliminating click-and-pop and minimizing power consumption by reducing DC leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the audio device operates in power-off or shutdown modes to reduce power consumption, then power consumption is reduced, but transient voltage offsets occur during mode transitions causing click-and-pop artifacts
Solution Approach 1:
The system performs preliminary action by gradually ramping down the audio signal amplitude before transitioning to shutdown mode, and gradually ramping up after power-on, preventing abrupt voltage transitions that cause click-and-pop artifacts while still achieving power savings
Solution Approach 2:
The system applies preliminary anti-action by introducing a compensating offset signal that counteracts the transient voltage offset before it can cause audible artifacts, effectively neutralizing the harmful effect during mode transitions
2Adaptability or versatility
If the audio signal is abruptly discontinued or resumed during mode transitions, then power consumption is reduced or operational flexibility is improved, but transient voltage offsets are generated causing audible click-and-pop
Solution Approach 1:
Before discontinuing the audio signal during shutdown, the system preliminarily reduces the signal amplitude over time, and before resuming operation, it preliminarily establishes a gradual ramp-up sequence, ensuring smooth transitions without abrupt voltage changes that generate harmful transients
Data Source
AI summary
A digital offset is combined with an audio signal in the digital domain to cancel an output offset caused by one or more analog components processing the same audio signal. In this manner, the offset at the output of the audio signal path (e.g., at a power amplifier output) is reduced or eliminated. Consequently, audible artifacts, such as click-and-pop artifacts, can be reduced or eliminated. In audio devices operating in ground-referenced capless mode, power consumption is reduced because of reduced or eliminated direct current (DC) leakage current through speakers or headsets of such audio devices. In some circumstances, the digital offset in the digital domain may be applied at substantially all times of operation of the audio signal path.