TPM Sensor Frequency Deviation Adjustment via Switchable Capacitors
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Solution Overview
Problem
Tire pressure monitoring (TPM) sensors with wide frequency deviations often suffer from in-band noise, leading to decreased sensitivity, and may not be compatible with narrow band receivers required by some OEMs, resulting in attenuation or failure to receive signals.
Innovation Solution
Implementing a phase locked loop (PLL) with a bank of capacitors that can be switched on or off to adjust frequency deviation dynamically, allowing TPM sensors to adapt their frequency-shift keying (FSK) signals to match different receiver bandwidths, using either internal or external capacitors to achieve the required frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wide frequency deviation is used in TPM sensors, then the receiver bandwidth can be wider and more cost effective, but in-band noise increases and sensitivity decreases
Solution Approach 1:
The patent applies dynamics by making the frequency deviation adjustable rather than fixed. The TPM sensor can dynamically change its frequency deviation based on the receiver bandwidth, allowing it to optimize between cost-effectiveness and sensitivity depending on the specific application requirements.
Solution Approach 2:
The patent changes the frequency deviation parameter to resolve the contradiction. By allowing the frequency deviation to be modified (from fixed wide deviation to adjustable deviation), the system can adapt to different receiver bandwidths, thereby balancing the trade-off between receiver cost-effectiveness and sensor sensitivity.
2Speed
If a wide frequency deviation is used in TPM sensors, then the transmission range is improved, but compatibility with narrow band receivers is lost causing signal attenuation or failure
Solution Approach 1:
The patent makes the frequency deviation dynamic and adjustable, allowing the sensor to adapt its transmission characteristics to match the receiver bandwidth. This resolves the contradiction by enabling the sensor to maintain good transmission range when paired with wide bandwidth receivers while ensuring compatibility with narrow band receivers when needed.
Solution Approach 2:
The patent changes the frequency deviation parameter based on the receiver type. By allowing modification of this parameter, the system achieves versatility in working with different receiver bandwidths while maintaining effective signal transmission across various automotive manufacturer protocols.
3Device complexity
If a fixed frequency deviation is chosen during engineering, then the sensor design is simplified, but the sensor cannot adapt to different receiver bandwidths required by various OEMs
Solution Approach 1:
The patent introduces dynamics to the frequency deviation, transforming it from a fixed design parameter to an adjustable one. This allows the sensor to maintain relatively simple design while gaining the ability to adapt to different OEM protocols and receiver bandwidths through programmable frequency deviation settings.
Solution Approach 2:
The patent makes the sensor universal by enabling it to work with multiple different receiver bandwidths. Through adjustable frequency deviation, a single sensor design can serve multiple OEMs with different protocol requirements, eliminating the need for multiple specialized sensor designs.
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
This approach enables TPM sensors to adjust their frequency deviation on the fly, ensuring compatibility with various receiver bandwidths, reducing noise interference and maintaining sensitivity while accommodating different automotive manufacturer protocols, thereby enhancing signal reception and reliability.
Implementation Method 1
Implementing a phase locked loop (PLL) with a bank of capacitors that can be switched on or off to adjust frequency deviation dynamically
Data Source
AI summary
A protocol to be used in the transmission is determined. Based upon the protocol, the transmission frequency range of a clock is selectively altered. TPMS data is transmitted according to the altered transmission frequency range of the clock.