Digital Microphone Circuit Noise Reduction via Randomized Processing
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Solution Overview
Problem
Traditional microphone processing methods result in periodic current modulation, leading to audible noise due to consistent processing patterns within frames, which affects sound quality without impacting size or performance.
Innovation Solution
A microphone assembly with an electrical circuit that processes digital data in discrete time periods within frames, varying the distribution of these periods and clock frequencies between frames to reduce noise, using techniques such as randomization and no-operation commands to minimize power consumption and acoustic disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If digital data are processed continuously within each frame at consistent intervals, then processing efficiency is maintained, but periodic current modulation occurs causing audible noise
Solution Approach 1:
The patent applies dynamics by making the processing schedule variable rather than fixed. The distribution of discrete time periods during which digital data are processed is changed from frame to frame, creating an irregular processing pattern that avoids periodic current modulation while maintaining overall processing efficiency.
Solution Approach 2:
The patent uses periodic action in reverse - it deliberately introduces aperiodic processing intervals. By varying the distribution of processing time periods across frames and using no-operation commands to create irregular intervals, the system eliminates the harmful periodic current modulation that causes audible noise.
2Reliability
If processing is performed at every discrete time period within frames, then data processing completeness is ensured, but power consumption increases due to continuous operation
Solution Approach 1:
The patent extracts unnecessary processing operations from the continuous processing sequence. By identifying and removing redundant processing steps, and replacing them with no-operation commands, the system reduces power consumption while ensuring that essential data processing completeness is maintained through selective processing at key discrete time periods.
Solution Approach 2:
The patent applies partial action by processing digital data at selected discrete time periods rather than at every possible moment. This selective processing approach uses no-operation commands during non-critical intervals, reducing overall power consumption while maintaining sufficient data processing completeness for audio quality.
3Device complexity
If consistent processing patterns are used within frames, then processing simplicity is maintained, but noise is generated due to periodic current modulation
Solution Approach 1:
The patent resolves this contradiction by introducing dynamic variation in processing patterns. While the overall frame structure remains simple, the distribution of processing time periods varies from frame to frame, creating an irregular pattern that eliminates periodic current modulation without significantly increasing system complexity.
Solution Approach 2:
The patent changes the temporal parameters of processing operations. By varying the timing and distribution of discrete processing time periods across frames, and using no-operation commands to adjust intervals, the system alters processing parameters to eliminate noise-generating periodicity while maintaining manageable complexity.
Data Source
AI summary
A microphone assembly includes a housing including a base, a cover, and a sound port. The microphone assembly further includes an acoustic transducer and an electrical circuit, both of which are disposed in an enclosed volume of the housing. The transducer and electrical circuit work in concert to convert sound waves into a processed digital audio signal. The electrical circuit is configured to process digital data in a series of frames that correspond to a fixed period in time. The electrical circuit is further configured to reduce noise in the resulting signal by varying the current draw required in a randomized or pseudo-randomized fashion between adjacent frames of digital data.