Source Device Adjusting HDMI Signal Waveform for Communication Reliability
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Solution Overview
Problem
HDMI and DVI communication systems experience communication failures due to deteriorated frequency characteristics, leading to abnormal pictures and sounds, as voltage levels of digital signals are not accurately transmitted, necessitating a solution to determine and improve the communication status between source and sink devices.
Innovation Solution
A source device determines the communication status using HDCP communication results and adjusts the communication signal by comparing decoding values, optimizing electrical characteristics such as waveform, peak-to-peak, rising and falling times, and jitter, and changing the frequency by adjusting bit depth or output resolution if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HDMI or DVI communication is used to provide high-definition contents, then content protection is achieved through HDCP signal, but communication failure occurs when frequency characteristic deteriorates due to long cable length
Solution Approach 1:
The source device performs preliminary HDCP communication to detect signal quality before actual content transmission. By comparing decoding values of HDCP signals in advance, the system identifies communication status and adjusts parameters proactively to prevent communication failure during content delivery
Solution Approach 2:
The system dynamically adjusts communication signal parameters including voltage level, waveform characteristics, and frequency based on detected communication status. When signal deterioration is detected, the source device changes these parameters to optimize signal transmission quality and maintain reliable communication
2Manufacturing precision
If communication signal frequency characteristic deteriorates due to long HDMI cable, then voltage levels of digital signals are not accurately transmitted, but adjusting communication parameters is required to maintain normal content provision
Solution Approach 1:
The system implements feedback mechanism by comparing the decoding value of received HDCP signal with the originally transmitted decoding value. This feedback loop enables automatic detection of signal deterioration and triggers appropriate parameter adjustments without user intervention
Solution Approach 2:
The source device automatically monitors its own communication status and performs self-adjustment of communication parameters. The system serves itself by detecting decoding value mismatches and autonomously adjusting voltage levels, waveforms, or frequency to maintain accurate signal transmission
Data Source
AI summary
A source device that provides contents to a sink device and a communication method thereof are provided. The communication method of the source device includes: transmitting a communication signal including a High-bandwidth Digital Content Protection (HDCP) signal to the sink device; determining a communication status with the sink device using an HDCP communication result received from the sink device; and adjusting the communication signal according to the determined communication status. Therefore, the communication method can provide a user with optimized contents.