Adaptive MOS Envelope Detection for RF Dynamic Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional envelope detectors face challenges in maintaining a precise bias point and maximizing conversion gain due to variations in average power of the radio frequency input signal, leading to distortion and limited dynamic range, especially in wireless communication applications.
Innovation Solution
An electronic envelope detection circuit that dynamically adjusts the gate bias voltage of transistors based on the average power of the input signal, allowing for adaptive polarization and extended dynamic range without requiring complex feedback stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional envelope detector uses a fixed bias point to maximize conversion gain, then the sensitivity is improved, but the dynamic range is limited and distortion occurs when input signal power varies
Solution Approach 1:
The patent applies the dynamics principle by making the bias point of the amplifier variable rather than fixed. A control circuit dynamically adjusts the bias voltage based on the detected average power level of the input signal, allowing the envelope detector to adapt to varying signal conditions and extend its dynamic range while maintaining optimal conversion gain at different power levels
Solution Approach 2:
The patent implements feedback by using a portion of the output signal to control the bias point of the amplifier. The control circuit monitors the output signal level and adjusts the bias voltage accordingly, creating a closed-loop system that automatically optimizes the operating point based on the actual signal conditions, thereby preventing distortion and maximizing dynamic range
2Reliability
If the average power of the radio frequency input signal varies, then the envelope detector must maintain precise bias point, but manufacturing process variations and temperature changes make this difficult or impossible
Solution Approach 1:
The patent applies self-service by designing a control circuit that automatically adjusts the bias point based on the actual operating conditions. The circuit monitors its own output signal level and self-corrects the bias voltage to maintain optimal operation, eliminating the need for external calibration or complex configuration procedures during manufacturing and operation
Solution Approach 2:
The patent changes the bias voltage parameter dynamically based on detected signal conditions. The control circuit measures the average power of the input signal and adjusts the bias point accordingly, allowing the system to adapt to manufacturing variations and environmental changes without requiring precise initial configuration
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The envelope detection electronic circuit includes a detection stage (7) having at least one MOS transistor (T1, T2, T5, T6, T7) configured to receive a radio frequency input signal (SER) and to deliver an internal signal (SI) from the input signal (SER), the average gate bias voltage of said at least one transistor (T1, T2, T5, T6, T7) being controlled by a control signal (SC), and a processing stage (8) coupled to the detection stage (7) and configured to deliver a low frequency output signal (SSB) from the internal signal (SI) and to deliver the control signal (SC) from the internal signal (SI), such that the value of the control signal (SC) decreases when the average power of the input signal (SER) increases, and vice versa.