HDMI Switch Clock Signal Detection for Accurate Input Selection
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Solution Overview
Problem
Current HDMI switches cannot automatically select an input with a valid video or audio signal, often choosing inactive sources due to the presence of a positive 5-volt power signal even when no video signal is transmitted, leading to incorrect output selection.
Innovation Solution
A multimedia device with a multiplexer and processor that detects a clock signal on HDMI inputs to automatically select and output a valid video or audio signal, using methods such as clock detect circuits, analog detection, and hot plug signals to differentiate between active and inactive sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an HDMI switch uses power voltage detection (positive 5 volts) to automatically select an input source, then the device achieves automatic input selection, but it incorrectly selects inactive sources that are in standby mode and not actually transmitting video signals
Solution Approach 1:
The patent changes the detection parameter from power voltage (5V) to clock signal presence. The processor detects whether a clock signal is actually being transmitted on the HDMI input rather than just detecting power availability. This parameter change allows the system to distinguish between standby mode (power present, no clock signal) and active mode (power present, clock signal present), resolving the contradiction between automation and detection accuracy.
2Measurement precision
If a user manually selects the input source on an HDMI switch, then the system ensures accurate selection of the desired source, but the user must know which source is connected to which input and intervene every time a source changes
Solution Approach 1:
The HDMI switch performs self-service by automatically detecting which input source is active through clock signal monitoring and autonomously selecting the correct input for output. The processor continuously monitors clock signals on each input and automatically switches the multiplexer to the active source without requiring user knowledge of source connections or manual intervention, thus achieving both accuracy and ease of operation.
3Measurement precision
If the HDMI switch monitors clock signals on all inputs to accurately detect active sources, then the system achieves precise automatic selection, but the device complexity and processing requirements increase
Solution Approach 1:
The patent extracts only the essential detection function needed to identify an active source - monitoring the clock signal presence - rather than implementing complex analysis of all HDMI signal components. The processor simply detects whether a clock signal is present on each input, which is sufficient to determine active vs. standby state, thereby achieving high detection accuracy with minimal added complexity.
Data Source
AI summary
A multimedia device is described. The multimedia device includes a multiplexer. The multimedia device also includes a plurality of high-definition interface inputs coupled with the multiplexer and an output coupled with the multiplexer. Moreover, the multimedia device includes a processor coupled with the multiplexer to configure the multiplexer to provide one of the plurality of high-definition multimedia interface inputs to the output based on the detection of a clock signal on one of the plurality of high-definition multimedia interface inputs. Furthermore, methods related to embodiments of a multimedia device are described herein.