Multi-Frequency RF Transmitter Rolling Code Switching
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Solution Overview
Problem
Existing wireless control systems face compatibility issues when operating at multiple frequencies, and existing trainable transmitters may not be compatible with all frequencies used by dual- or multiple-frequency systems, necessitating a transmitter that can transmit RF control signals at multiple frequencies in response to a single user input.
Innovation Solution
A transmitter with a user input device, memory storing control data for multiple frequencies, and a transmitter circuit that generates and transmits a rolling code signal at a first frequency for a predetermined time before switching to a second frequency upon expiration of that time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a transmitter is designed to operate at a single frequency, then the device complexity is reduced, but the adaptability to multiple-frequency wireless control systems deteriorates
Solution Approach 1:
The transmission process is segmented into multiple time slots, each dedicated to a specific frequency. The transmitter divides the rolling code message transmission into sequential segments at different frequencies rather than attempting simultaneous multi-frequency transmission, reducing circuit complexity while maintaining multi-frequency capability
Solution Approach 2:
The transmitter dynamically switches between different frequencies based on time slots. The system transitions from a static single-frequency operation to a dynamic multi-frequency operation, where the operating frequency changes over time according to a predefined schedule, enabling adaptability without requiring complex multi-frequency circuitry
2Adaptability or versatility
If rolling code messages are transmitted at multiple frequencies simultaneously, then compatibility with multiple-frequency systems is improved, but the loss of time for message transmission increases
Solution Approach 1:
The transmitter employs periodic action by sending the rolling code message at regular time intervals across different frequencies. Instead of attempting simultaneous transmission, the system uses periodic transmissions at sequential time slots, where each frequency receives the message at a different time, ultimately achieving the same security verification outcome
Solution Approach 2:
The system performs preliminary action by pre-defining the transmission schedule and time slots for each frequency before actual message transmission begins. This planning allows the receiver to anticipate and properly process messages arriving at different frequencies at different times, eliminating the need for simultaneous transmission
3Reliability
If the transmission time at each frequency is extended, then the reliability of message reception is improved, but the loss of time for completing multi-frequency transmission increases
Solution Approach 1:
The transmitter applies partial action by sending only the essential portions of the rolling code message at each frequency within predetermined time slots. Rather than transmitting the complete message duration at every frequency, the system uses sufficient but limited transmission time at each frequency, achieving reliable reception without excessive total transmission time
Solution Approach 2:
The system changes the time parameter dynamically based on the frequency being used. Each frequency is allocated a specific time slot duration optimized for that frequency's characteristics, allowing the transmission time parameter to vary according to the operating frequency rather than maintaining a fixed transmission time across all frequencies
Data Source
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AI summary
A transmitter for transmitting an RF control signal to a remote system includes a user input device, a memory and a transmitter circuit. The memory includes control data associated with the remote device. The control data includes a first frequency and a second frequency. The transmitter circuit is coupled to the user input device and memory. In response to a single user input, the transmitter circuit generates a rolling code signal, transmits the rolling code signal at the first frequency for a predetermined amount of time, and, upon expiration of the predetermined about of time, transmits the rolling code signal at the second frequency.