Filtering HDMI Signals to Reduce Wireless Interference

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Solution Overview

Problem

The interference between wired interfaces and wireless interfaces in electronic devices, such as HDMI and wireless networking, leads to decreased wireless range and throughput due to radiated energy from wired interfaces being absorbed by wireless antennas or circuitry, especially in compact devices where these interfaces are closer together.

Innovation Solution

Implementing a filter, such as a bandstop or lowpass filter, to attenuate specific frequency bands used by wireless interfaces, reducing energy content in those bands within wired interface signals, thereby minimizing interference. This can be achieved using digital or analog filters before output signals are sent, with optional selectable controls for frequency range adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If wired and wireless interfaces are placed closer together in compact devices, then device size is reduced, but wireless receiver sensitivity deteriorates due to increased radiative coupling

Engineering Contradiction:

Improvedevice sizeVSAvoidwireless receiver sensitivity

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

A filter is introduced as an intermediary component between the wired interface (HDMI) and the external connector. This filter mediates the signal transmission by selectively attenuating frequency components that would otherwise radiate and interfere with the wireless receiver, thus protecting wireless sensitivity while allowing the wired interface to operate at full speed.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The filter modifies the frequency spectrum parameter of the HDMI signal by attenuating specific frequency ranges (particularly 2.4-2.5 GHz and 5.725-5.875 GHz bands) while preserving other frequency components. This parameter change reduces radiated energy in wireless frequency bands without completely disabling the wired interface functionality.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If high speed wired interfaces are used, then data transmission capability is improved, but radiated energy increases causing interference with wireless interfaces

Engineering Contradiction:

Improvedata transmission capabilityVSAvoidradiated energy

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The filter extracts and removes the harmful high-frequency components from the HDMI signal spectrum. By taking out the specific frequency ranges that cause wireless interference (particularly those overlapping with ISM and UNII bands), the filter allows the high-speed data transmission to continue while eliminating the radiated energy that causes harm to wireless communications.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The filter converts the potentially harmful high-frequency radiated energy into a beneficial filtered signal. By selectively attenuating only the problematic frequency components while preserving the essential data transmission frequencies, the harmful radiated energy is transformed into a controlled signal that maintains data transmission capability without causing wireless interference.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If HDMI signal frequency content overlaps with wireless interface frequencies, then wired interface functionality is maintained, but wireless throughput decreases due to noise absorption

Engineering Contradiction:

Improvewired interface functionalityVSAvoidwireless throughput

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The filter applies localized frequency-selective attenuation rather than uniform signal suppression. By targeting specific frequency bands (2.4-2.5 GHz, 5.725-5.875 GHz) where overlap with wireless interfaces occurs, the filter preserves wired interface functionality in other frequency ranges while eliminating interference in the problematic local frequency zones.

Inventive Principle:

Principle #3Local quality

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

The solution effectively reduces wireless interference by selectively attenuating energy in frequency ranges used by wireless interfaces, enhancing wireless performance and maintaining compliance with standards for wired interfaces like HDMI, thus improving the overall functionality of devices with both wired and wireless connections.

Implementation Method 1

a filter configured to attenuate the wired interface output signal, such that the filter attenuates portions of the wired interface output signal which have energy in the second frequency band

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Data Source

PatentUS10536225B2Reducing wireless interference from a wired digital interface

Publication Date: 2020.01.14 ARRIS ENTERPRISES LLC

AI summary

Circuits and systems may be operable to provide improved wireless networking performance in the presence of a high speed wired interface. Filter circuits may be applied to wired interface leads to suppress frequency content that may interfere with wireless home networking. High speed digital wired interface systems on a chip may similarly be altered to suppress interfering frequency content before it leaves the chip. Systems with reduced radiated energy from wired interface circuits in frequencies of interest to wireless networking have improved wireless range and throughput characteristics.