HDMI Echo Cancellation via Clock Domain Synchronization
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Solution Overview
Problem
In HDMI 1.4 signal transmission, echo signals can degrade received signal quality as they are not distinguishable from actual signals, leading to connection failures, especially when echo cancellers operate under different clock domains or at inappropriate timings.
Innovation Solution
A method and device that adjust the clock frequency of transmitted signals to match received signals, perform echo cancellation, and compute the distance between certification codes to determine if the echo canceller should be turned on or off, simplifying the design and operation of echo cancellers by ensuring both signal paths operate under the same clock domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an echo canceller is disposed in the network device to eliminate echo signals, then the received signal quality is improved, but the design complexity increases when operating under different clock domains
Solution Approach 1:
The patent adjusts the clock frequency parameter of the transmitting signal to match the clock frequency of the received signal. By changing the clock frequency parameter to be consistent between transmit and receive paths, the echo canceller can operate under a unified clock domain, thereby reducing design complexity while maintaining signal quality improvement
2Adaptability or versatility
If the echo canceller operates under different clock domains, then the transmitting and receiving functions can be independent, but the design becomes very complicated
Solution Approach 1:
The patent merges the clock domains of the transmitting and receiving paths by adjusting the transmitting clock frequency to match the receiving clock frequency. This unification allows the echo canceller to operate under a single clock domain while preserving the functional independence of transmitting and receiving operations, thereby reducing design complexity
3Device complexity
If the echo canceller does not turn on/off at the appropriate timing, then the circuit structure remains simple, but it may fail to cancel the echo signal correctly or affect the signals to be transmitted/received
Solution Approach 1:
The patent employs a feedback mechanism where the control unit monitors the operational state and timing of the echo canceller, adjusting its on/off timing based on the actual signal conditions. This feedback control ensures accurate echo cancellation while maintaining circuit simplicity, as the control logic dynamically adapts to operational requirements
Data Source
AI summary
A signal transceiving method, applied to a signal transceiver, includes: adjusting to approximate a value of a clock frequency of a signal to be transmitted from the signal transceiver to a value of a clock frequency of a received signal; performing an echo cancellation operation; computing a distance between a first certification code transmitted by the signal transceiver and a second certification code received by the signal transceiver; and stopping the echo cancellation operation when the distance is smaller than a threshold value.