Reception device and communication system
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Solution Overview
Problem
Existing air-conditioning systems with long three-core cables face noise interference due to capacitance between lines, affecting communication reliability, and previous noise resistance techniques become inappropriate when circuit parameters change, such as during air conditioner replacement.
Innovation Solution
A reception device with a voltage application circuit, determination means, and threshold switch means that adjusts the current threshold for communication current detection based on the communication current intensity, using a voltage adjustment circuit to ensure reliable communication by switching the current threshold in accordance with circuit parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed resistor is installed in parallel with the light-emitting device to improve noise resistance, then the current threshold for communication current detection is increased, but when circuit parameters change (e.g., during air conditioner replacement), the resistance becomes inappropriate and noise resistance decreases
Solution Approach 1:
The patent applies the dynamics principle by making the current threshold adjustable rather than fixed. The reception device includes a threshold adjustment unit that can dynamically change the current threshold value based on detected communication current intensity. This resolves the contradiction by allowing the system to adapt to different circuit parameters (different air conditioners) while maintaining high noise resistance through optimal threshold selection.
Solution Approach 2:
The patent applies parameter changes by modifying the current threshold parameter based on detected communication current characteristics. The system detects the actual communication current intensity and adjusts the threshold parameter accordingly, rather than using a fixed parameter. This allows the reception device to adapt to different circuit configurations and maintain reliable communication across various air conditioner models.
2Reliability
If the current threshold is increased to prevent noise interference, then false detection of communication current is reduced, but legitimate communication current detection may also be affected
Solution Approach 1:
The patent applies feedback by using the detected communication current intensity to adjust the current threshold. The system continuously monitors the communication current characteristics and feeds this information back to the threshold adjustment unit, which modifies the threshold to optimize both noise rejection and legitimate signal detection. This closed-loop approach resolves the contradiction by dynamically balancing false detection prevention with accurate signal recognition.
Solution Approach 2:
The system dynamically adjusts the current threshold based on real-time detection of communication current intensity, rather than using a static threshold. This dynamic adaptation allows the system to maintain high detection accuracy across varying communication conditions while preventing false detections from noise interference.
Data Source
AI summary
A voltage application circuit including a photocoupler and a resistor applies, to a reception terminal, a voltage corresponding to an intensity of a communication current flowing through a transmission path. A reception control unit determines whether the communication current is flowing, by comparing the voltage applied to the reception terminal with a predetermined voltage threshold. A voltage adjustment circuit including a resistor and a transistor adjusts the voltage that is applied to the reception terminal by the voltage application circuit. A switch control unit switches a current threshold used for determining whether the communication current is flowing by controlling the voltage adjustment circuit in accordance with an intensity of the communication current during an on-control period.