Microphone System Signal Path Separation for Noise Reduction
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Solution Overview
Problem
In existing microphone systems, noise from the digital circuit can be transmitted to the analog circuit via the common ground (GND), degrading the characteristics of the analog circuit and affecting sound quality.
Innovation Solution
The microphone system separates the signal path for the input sound signal from the power supply path by using a pair of first signal lines different from the pair of power supply lines, even when a potential difference occurs in the circuit GND between the first and second circuit boards, thereby suppressing noise and improving sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common circuit GND is used for both analog and digital circuit portions, then device complexity is reduced, but noise from the digital circuit is transmitted to the analog circuit via the GND, degrading analog circuit characteristics
Solution Approach 1:
The patent divides the common GND into separate analog GND and digital GND portions, creating distinct ground paths for analog and digital circuits. This segmentation prevents noise from the digital circuit from being transmitted to the analog circuit through the GND, thereby resolving the contradiction between device simplicity and noise interference.
2Object-affected harmful factors
If power supply lines are separated for digital and analog circuits, then noise generation is reduced, but device complexity increases
Solution Approach 1:
The patent implements segmentation by separating power supply lines into distinct analog and digital power supply paths, while also segmenting the GND into analog and digital portions. This dual segmentation approach effectively reduces noise generation by preventing digital noise from affecting analog circuits, while maintaining a structured and manageable circuit configuration.
Data Source
AI summary
A microphone system includes: a microphone including a microphone output terminal and a microphone GND terminal, the microphone being configured to output, as an input sound signal, a voltage signal exhibiting a change in voltage between the microphone output terminal and the microphone GND terminal depending on an input sound; an A/D converting unit mounted on a first circuit board and configured to perform digital conversion on the input sound signal that is input; and a power supply circuit mounted on a second circuit board connected to the first circuit board via a pair of power supply lines, and configured to feed DC power to the A/D converting unit via the pair of power supply lines. The microphone outputs the input sound signal to the A/D converting unit via a pair of first signal lines different from the pair of power supply lines.