Cable Noise Attenuation via Resonance-Positioned Ferrite Cores
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Solution Overview
Problem
High-frequency noise due to resonance frequencies generated in communication devices, such as image forming apparatuses, causes malfunctions and poor image quality, particularly when ferrite cores are only placed at the end portions of cables.
Innovation Solution
The implementation of noise attenuation units, specifically ferrite cores, are positioned at specific regions along the cable corresponding to n-th order resonance frequencies, including positions near antinodes and other maximization regions, to effectively attenuate high-frequency currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ferrite cores are disposed only at both end portions of a cable, then the device complexity is reduced and ease of manufacture is improved, but high-frequency noise attenuation is insufficient and reliability deteriorates
Solution Approach 1:
The cable is divided into multiple sections along its length, with ferrite cores disposed at strategically selected positions including end portions and intermediate positions. This segmentation approach allows the noise attenuation function to be distributed across multiple locations, effectively addressing resonance frequencies at different points along the cable while maintaining a manageable manufacturing process.
Solution Approach 2:
Different regions of the cable are treated differently by placing ferrite cores at specific positions where resonance occurs. Instead of uniform distribution or only at ends, the solution applies local quality by identifying and treating specific problem areas (resonance regions) along the cable length, optimizing noise attenuation where it is most needed.
2Reliability
If ferrite cores are disposed at multiple positions along the cable, then noise attenuation effectiveness is improved and reliability is enhanced, but device complexity increases and ease of manufacture deteriorates
Solution Approach 1:
The cable shielding structure is segmented into multiple sections along its longitudinal axis, with ferrite cores strategically positioned at end portions and intermediate positions. This segmentation enables effective noise attenuation across different resonance frequencies without requiring a completely complex design, as each segment addresses specific frequency ranges.
Solution Approach 2:
The ferrite cores serve multiple functions: they provide magnetic shielding, attenuate high-frequency noise, and address resonance at different frequencies simultaneously. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity despite the multi-position configuration.
3Reliability
If ferrite cores are disposed at multiple positions along the cable, then high-frequency noise attenuation is improved, but the loss of time for installation and assembly increases
Solution Approach 1:
The ferrite cores are pre-positioned at specific locations along the cable during manufacturing, including end portions and intermediate positions. This preliminary action ensures that when the cable is installed, the noise attenuation functionality is already in place, reducing the time required during actual installation and assembly operations.
Solution Approach 2:
The cable is manufactured as segmented sections with ferrite cores already positioned at appropriate locations. This segmentation allows for modular assembly where pre-configured cable sections can be quickly connected, reducing the overall installation time compared to assembling a single long cable with multiple cores after installation.
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 configuration significantly reduces high-frequency noise across multiple resonance frequencies, preventing malfunctions and improving image quality by effectively managing resonance-induced electromagnetic interference.
Implementation Method 1
a resonance frequency generated in accordance with a combination of the length of the image sensor in a longitudinal direction and the length of the first cable is equal to or higher than 230 MHz
Implementation Method 2
techniques disclosed in JP5230369B, JP5428936B, and JP2001-111287A have already been proposed
Data Source
AI summary
A communication device includes a transmission-side board that transmits a signal, a reception-side board that receives the signal transmitted from the transmission-side board, a cable for connecting the transmission-side board and the reception-side board, and plural noise attenuation units that attenuate high frequency noise and are disposed at plural positions in a maximization region of a high frequency current corresponding to plural n-th order resonance frequencies, the plural positions including portions of the cable other than an end portion of the cable, the plural n-th order resonance frequencies being determined by a length of the cable, and n being an integer of 1 or more.