RFID Transmitter With Audio-Modulated Attenuation Circuit
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Solution Overview
Problem
RFID remote controls often inadvertently match with unintended electronic devices due to their fixed transmission range, leading to unintended communication with non-target devices.
Innovation Solution
A range-variable transmitter with an amplifier, transmission module, power supply, attenuation circuit, and analog-to-digital converter, which uses audio signals to modulate carrier signals and adjust transmission distance through an attenuation circuit, allowing for precise antenna matching with target devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the transmitter uses enough emitting power to ensure all electronic devices can receive RF signals, then the transmission coverage is improved, but unintended devices can also receive the signal causing interference
Solution Approach 1:
The patent implements dynamic transmission range adjustment by varying the attenuation level based on the detected audio signal strength. The transmitter switches between different attenuation states (e.g., 0dB for strong signals, 10dB for moderate signals, 20dB for weak signals) to adaptively control the transmission distance, allowing the system to expand coverage when needed while reducing interference when the target is close by.
2Device complexity
If the transmitter uses fixed transmission range, then the device complexity is reduced, but the adaptability to different distances and devices is worsened
Solution Approach 1:
The patent implements self-service through automatic attenuation adjustment based on audio signal feedback. The system continuously monitors the audio signal strength from the target device and automatically selects the appropriate attenuation level without requiring manual intervention or complex user input. This self-regulating mechanism provides adaptive transmission range control while keeping the user interface simple.
3Length of stationary object
If the transmitter sends strong RF signals to ensure communication with distant devices, then the transmission distance is improved, but unintended close devices may also receive the signal
Solution Approach 1:
The patent employs feedback control by monitoring the audio signal strength returned from the target device and using this information to adjust the transmission attenuation. The system measures the audio signal level, compares it against threshold values, and automatically adjusts the attenuation level accordingly. This closed-loop feedback mechanism ensures that the transmitter sends strong signals only when the target is distant while reducing power when the target is close, preventing unintended device reception.
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
Enables selective communication with target electronic devices by adjusting the transmission range from 10 cm to 30 meters based on audio signal modulation, reducing interference with other devices.
Implementation Method 1
an amplifier configured to receive a first audio signal from an electronic device and amplify the first audio signal
Implementation Method 2
a transmission module electrically connected to the amplifier to receive the amplified first audio signal and generate a carrier signal; the amplified first audio signal is configured to modulate the carrier signal
Implementation Method 3
an attenuation circuit electrically connected to the transmission module to receive the carrier signal and output an attenuated carrier signal
Data Source
AI summary
A transmitter for remote control, the transmitter includes an amplifier configured to receive a first audio signal from an electronic device and amplify the first audio signal, a transmission module electrically connected to the amplifier to receive the amplified first audio signal and generating a carrier signal, a power supply connected to the transmission module, and an attenuation circuit electrically connected to the transmission module to receive the carrier signal, wherein the amplified first audio signal is configured to modulate the carrier signal and the first audio signal is one of a left channel audio signal and a right channel audio signal output from the electronic device via an audio connector.