Microphone Assembly RFI Suppression via Ribbon Wire Grounding
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Solution Overview
Problem
Conventional microphone assemblies for hearing aids suffer from poor radio-frequency interference (RFI) suppression, particularly when near communication devices like cellular phones, and often require additional and costly assembly steps for effective RFI reduction.
Innovation Solution
The microphone assembly incorporates a ribbon wire with low inductance and RF resistance, coupled with a preamplifier assembly featuring a hybrid circuit and flex circuit, which reduces inductive reactance and provides effective RFI suppression through a short grounding path, eliminating the need for complex grounding wire connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional microphone assemblies use capacitive coupling with preamplifier assembly and external ground wirings to reduce RFI sensitivity, then RFI suppression is improved, but device complexity and manufacturing cost increase due to additional assembly steps for connecting and positioning ground wires
Solution Approach 1:
The patent combines the ground wiring function with the existing microphone assembly structure by integrating the ground connection into the microphone housing or casing. This merging eliminates the need for separate external ground wires and their complex positioning and connection steps, while maintaining effective RFI suppression through the integrated grounding path.
2Object-affected harmful factors
If conventional microphone assemblies add external and internal ground wirings to connect microphone casing portions, then RFI sensitivity is reduced, but manufacturing cost increases due to additional costly assembly steps
Solution Approach 1:
The patent implements self-service grounding where the microphone assembly structure itself provides the ground path. The housing or casing is designed to serve as the ground connection medium, eliminating the need for separate ground wiring components and their associated assembly steps. This reduces manufacturing cost while maintaining RFI suppression effectiveness.
3Reliability
If known microphone assemblies use additional ground wires to provide acceptable RFI suppression, then RFI suppression performance is improved, but assembly process complexity and cost increase
Solution Approach 1:
The patent extracts the ground wiring function from the assembly process and integrates it into the microphone housing structure. By taking out the separate ground wire component and its complex positioning and connection steps, the design maintains effective RFI suppression while significantly simplifying the assembly process and improving productivity.
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 design significantly reduces undesirable RFI interference while simplifying the assembly process, enhancing the performance and attractiveness of hearing aid microphones by improving RFI suppression without additional costly steps.
Implementation Method 1
ribbon wire with low inductance and RF resistance
Implementation Method 2
ribbon wire with low inductance and RF resistance
Implementation Method 3
reduces inductive reactance
Data Source
AI summary
A microphone assembly comprises a housing that includes a conductive material. A preamplifier circuit is disposed within the housing, the preamplifier circuit having a signal input and a ground terminal. A microphone portion is disposed within the housing, the microphone portion having an output coupled to the signal input of the preamplifier circuit. A ribbon wire is attached to the ground terminal of the preamplifier circuit and is attached to the housing.