RF Power Detection With Sample-Based RMS Correction
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Solution Overview
Problem
Existing power detection methods in RF circuits for vehicles suffer from inaccuracies due to variations in signal modulation and temperature, with diode detectors providing insufficient accuracy and true RMS detectors being costly, making them undesirable for high-volume systems.
Innovation Solution
A module comprising a gain modifier, power detector, and controller is used to sample and calculate a real RMS value by determining a mean and boundary-to-mean ratio of RF power detector signals, adjusting the detected value to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a diode detector is used for power detection, then the system cost is low, but the measurement precision is insufficient due to modulation variations
Solution Approach 1:
The patent introduces an intermediary processing stage between the diode detector and the final power measurement. A detector circuit processes the RF signal through rectification, followed by a controller that performs sampling, mean calculation, and boundary-to-mean ratio correction. This intermediary processing chain enables a low-cost diode detector to achieve accuracy comparable to expensive true RMS detectors by applying mathematical corrections to the detector output.
2Measurement precision
If a true RMS detector circuit is used, then the measurement precision is substantially improved, but the device complexity and cost increase substantially
Solution Approach 1:
The patent creates a simplified copy of the true RMS detection function using a diode detector combined with digital signal processing. Instead of implementing the complex analog true RMS circuitry, the system uses a simple diode detector followed by a controller that calculates the mean and boundary-to-mean ratio of sampled signals, then applies correction factors. This copying approach replicates the accuracy of true RMS detectors while maintaining the simplicity and low cost of diode detector architecture.
3Adaptability or versatility
If temperature compensation is implemented using look-up tables, then the adaptability to temperature variations is improved, but the measurement precision deteriorates due to lack of feedback control
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the detector output, calculates the mean and boundary-to-mean ratio, and uses this information to determine correction factors. The system samples the detector signal multiple times, computes statistical parameters, and applies real-time corrections based on the calculated ratios. This feedback loop maintains measurement precision across varying temperatures and signal conditions without relying solely on pre-stored look-up tables.
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 precise determination of RF power output, enhancing gain control and ensuring compliance with RF standards, particularly for V2X communications, while maintaining cost-effectiveness.
Implementation Method 1
The most straightforward way to measure power level is through the use of a diode detector. Such detectors typically use rectification to convert the RF signal into a DC signal and thus provide a voltage that can be used to determine the RF power.
Data Source
AI summary
Exemplary embodiments are disclosed of methods and systems of power detection in RF circuits to provide gain compensation for vehicle systems. In exemplary embodiments, a module (e.g., a front end module (FEM), compensor, compensator, etc.) includes a gain modifier, a power detector, and a controller. The power detector is configured to detect a power output of the gain modifier. The controller is configured to determine a mean of n samples taken by the power detector. The controller is also configured to determine a boundary to mean ratio of the n samples. The controller is further configured to adjust a detected value of the power detector based on the mean and the boundary to mean ratio.