Audio Channel Switching Timed to Temporal Masking Windows
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Solution Overview
Problem
Audio processing systems, especially those using adaptive noise-cancelling (ANC) technology, face issues with audible artifacts due to changes in audio channel configurations such as gain or DC offset shifts, which cannot be masked by muting and occur even when the audio channel is not actively reproducing the program signal.
Innovation Solution
The system employs a signal level detector to determine a masking time interval based on the audio input signal's content and generates a control signal to synchronize changes in the audio processing channel's characteristics, such as gain or path selection, within this interval, leveraging temporal masking properties to minimize the audibility of transients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If configuration changes are made to the audio processing channel, then the system can adapt to different operating conditions and power requirements, but audible artifacts such as pops or clicks are generated
Solution Approach 1:
The system performs preliminary detection of signal level and determination of masking time intervals before executing configuration changes. The controller identifies appropriate masking windows in advance and schedules the configuration changes to occur within these intervals, ensuring that artifacts will be masked by the audio signal before they become audible.
Solution Approach 2:
The system converts the naturally occurring temporal masking effect of the audio signal into a beneficial mechanism for suppressing configuration change artifacts. By timing configuration changes to coincide with periods where the audio signal provides masking, the harmful artifacts are transformed into inaudible events that occur during naturally masked intervals.
2Object-generated harmful factors
If muting is applied to the audio channel during configuration changes, then artifacts may be suppressed, but the channel cannot be used for ANC applications where the program audio may be absent
Solution Approach 1:
The system performs preliminary detection of signal level and determination of masking time intervals before executing configuration changes. The controller identifies appropriate masking windows in advance and schedules the configuration changes to occur within these intervals, ensuring that artifacts will be masked by the audio signal before they become audible.
Solution Approach 2:
The system converts the naturally occurring temporal masking effect of the audio signal into a beneficial mechanism for suppressing configuration change artifacts. By timing configuration changes to coincide with periods where the audio signal provides masking, the harmful artifacts are transformed into inaudible events that occur during naturally masked intervals.
3Productivity
If configuration changes are made during reproduction, then the system can dynamically adjust to changing conditions, but shifts in DC offset or gain cannot be masked by muting
Solution Approach 1:
The system performs preliminary detection of signal level and determination of masking time intervals before executing configuration changes. The controller identifies appropriate masking windows in advance and schedules the configuration changes to occur within these intervals, ensuring that artifacts will be masked by the audio signal before they become audible.
Solution Approach 2:
The system converts the naturally occurring temporal masking effect of the audio signal into a beneficial mechanism for suppressing configuration change artifacts. By timing configuration changes to coincide with periods where the audio signal provides masking, the harmful artifacts are transformed into inaudible events that occur during naturally masked intervals.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces the audibility of artifacts caused by system configuration changes by aligning them with periods of sufficient masking energy in the audio signal, ensuring that changes occur during intervals where the signal's energy masks the transient, thereby reducing the perceived noise.
Implementation Method 1
determines a masking time interval available from the audio output signal due to signal content in the audio input signal
Data Source
AI summary
An audio processing system reduces perception of audible artifacts due to changes in an element in an audio channel of the audio processing system. The system reproduces an audio input signal and produces an audio output signal with the audio channel. The channel has an adjustable or selectable element that, responsive to a control signal, changes a characteristic of the audio processing channel, which generates a transient in the audio output signal. The systems include a level detector for measuring a signal level of the audio input signal and a controller responsive to an output of the level detector to determine a masking time interval available from the audio output signal due to signal content in the audio input signal. The controller generates the control signal to change the characteristic of the audio processing channel so that at least a portion of the transient occurs in the masking time interval.