Automatic-Gain RMS Detector for Wide Dynamic Signal Ranges
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Solution Overview
Problem
Existing RMS detectors face challenges in accurately processing signals with large peak-to-average ratios due to voltage variations that lead to noise offset issues and overload distortion, limiting their functionality in diverse communication systems.
Innovation Solution
The implementation of multiple variable-gain stages with automatic gain control feedback mechanisms that stabilize the squarer output, preventing saturation and distortion by maintaining constant signal levels across the squarer and averager, thereby allowing the RMS detector to operate within a wider dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a squarer is used to detect RMS voltage in signals with large peak-to-average ratios, then the RMS detection function is provided, but voltage variations are greatly amplified causing noise offset issues and overload distortion
Solution Approach 1:
The patent applies dynamics by making the gain of the squarer variable rather than fixed. The squarer gain is dynamically adjusted based on the input signal level to keep the squared output within a predetermined range, preventing both noise offset issues at low levels and overload distortion at high levels while maintaining accurate RMS detection across varying signal conditions
Solution Approach 2:
The patent implements feedback by using the squared output signal to control the gain of the squarer. A feedback loop monitors the squared output level and automatically adjusts the squarer gain to maintain the output within the optimal range, thereby eliminating the harmful effects of voltage variations while preserving the RMS detection function
2Adaptability or versatility
If the squarer operates outside its squaring region to handle large voltage swings, then the dynamic range is extended, but the squarer loses its squaring functionality and generates distortion
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting the squarer gain based on input signal conditions. The variable gain ensures that even when processing signals with large peak-to-average ratios, the squared output remains within the linear squaring region of the squarer, maintaining both the extended dynamic range capability and the accurate squaring functionality
Solution Approach 2:
The patent changes the gain parameter of the squarer dynamically to adapt to different input signal levels. By adjusting this parameter, the system can handle a wide dynamic range of input signals while keeping the squarer operating point within its optimal squaring region, preventing distortion and maintaining measurement accuracy
Data Source
AI summary
Embodiments of the present invention provide systems, devices and methods for detecting the RMS value of a signal. The RMS detector uses multiple variable-gain stages and internal gain control to generate an RMS output signal based on an arbitrary signal input. This RMS detector significantly reduces the signal swings seen on a squarer within prior art RMS detectors and reduces the detector's dependency on DC offsets at low signal levels and overload errors at high signal levels. The embodiments of the present invention also improve the accuracy of the RMS detector within large dynamic signal ranges by obviating the operation of a squarer in saturation or out of the squaring region. Accordingly, embodiments of the present invention are able to more accurately detect RMS values on a signal, operate over relatively higher signal ranges, and better function within different signal modulation schemes, particularly those with large peak-to-average ratios.