Receiver Chain Peak Detection for Interference-Aware AGC
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Solution Overview
Problem
Receivers in communication devices face signal distortion and data loss due to saturation when applying high gains to both data-bearing and interference components, especially before filter stages, which existing AGC systems do not adequately address.
Innovation Solution
A receiver chain with a parallel control path that preserves interference for AGC determination, using separate feedback loops to manage gain based on both data-bearing and interference signal strengths, allowing for increased gain in low-interference situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high gain is applied to amplify weaker signals, then sensitivity is improved, but signal saturation and distortion occur when stronger signals are amplified
Solution Approach 1:
The feedback path is segmented into two separate paths: a main path that filters interference to measure only data-bearing signal strength, and a control path that preserves interference to measure total signal strength. This segmentation allows the AGC to independently assess and control gain based on both data signal and interference components, resolving the contradiction between sensitivity and saturation.
Solution Approach 2:
The patent implements a dual-feedback AGC system where the control circuit receives feedback from both the main path (filtered data signal) and the control path (total signal with interference). This feedback mechanism enables dynamic gain adjustment that prevents saturation from interference while maintaining sensitivity for weak data signals, directly addressing the technical contradiction.
2Measurement precision
If filter stages are used to remove interference, then data-bearing signal quality is improved, but interference information is lost for AGC determination
Solution Approach 1:
The signal processing path is divided into two segments: the main path applies filtering to preserve data-bearing signal quality, while the control path preserves interference components for AGC measurements. This segmentation allows both objectives to be achieved simultaneously without compromising either data quality or interference information.
Solution Approach 2:
The control path acts as an intermediary that preserves the full signal spectrum including interference, providing the AGC circuit with complete information about total signal strength. This intermediary path enables the system to make informed gain decisions based on both data and interference components while the main path maintains high data quality through filtering.
3Device complexity
If single feedback path is used for AGC control, then system complexity is reduced, but accurate gain control based on both data and interference signal strength cannot be achieved
Solution Approach 1:
The feedback system is segmented into two functional paths with distinct purposes: the main path for data quality monitoring and the control path for total signal measurement. This segmentation, while increasing structural complexity, enables precise gain control by providing the AGC circuit with separate measurements of data signal strength and total signal strength including interference.
Solution Approach 2:
The dual-path feedback system serves multiple functions: the main path ensures data-bearing signal quality through filtered measurement, while the control path provides interference-aware gain control. This multi-functionality allows a single AGC circuit to simultaneously optimize for both data quality and interference management, achieving high measurement precision despite the increased system complexity.
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An integrated circuit device (100) is provided. In some examples, the integrated circuit device (100) includes an amplifier stage (106) that receives an input signal (102 A) and a control signal (110) and provides an amplified signal (102B) in response. A main path (116, 120, 122) is coupled to the amplifier stage (106) that receives the amplified signal and provides a first feedback signal (124) corresponding to a signal strength of a data-bearing portion of the input signal (102A). A control path (126, 128, 134) also receives the amplified signal (102B) and provides a second feedback signal (136) corresponding to a signal strength of the data-bearing portion and an interference component. A gain control circuit (108) is coupled to the main path (116, 120, 122) and the control path (126, 128, 134) that receives the first and second feedback signals (124, 136) and provides the control signal (110) in response to the feedback signals. In some such examples, the control path (126, 128, 134) and main path (116, 120, 122) include separate mixer stages (116, 126) with different performance characteristics.