Automatic Gain Control Circuit State Capture for Signal Disruption
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Solution Overview
Problem
Conventional automatic gain control (AGC) systems in wireless communication receivers face issues with signal disruptions, such as temporary loss of signal or jamming, leading to saturation problems and control lags during transitions between normal and disrupted conditions.
Innovation Solution
The method involves capturing and storing AGC settings prior to signal disruptions, allowing the AGC circuit to reset or maintain control using remembered information during disruptions, thereby compensating for signal strength variations and preventing saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional AGC functions are used to track received signal strength and adjust receiver gain, then the input signal range can be maintained for ADC digitization, but saturation problems occur when the received signal returns after temporary loss or disruption
Solution Approach 1:
The system performs preliminary action by capturing and storing the AGC filter state information before signal disruption occurs. When disruption is detected, the stored pre-disruption state is restored, preventing the saturation problem that would otherwise occur when the signal returns after temporary loss.
Solution Approach 2:
The system uses feedback by monitoring the received signal for disruption conditions and adjusting the AGC behavior accordingly. When disruption is detected, the system switches to using stored pre-disruption state information, and when normal signal conditions are restored, the system transitions back to normal AGC operation.
2Ease of operation
If conventional AGC functions ramp receiver gain upward during signal loss to boost low or non-existent signal strength, then proper AGC functionality is maintained, but temporary saturation problems occur when the received signal returns
Solution Approach 1:
The system captures the AGC filter state information before signal disruption occurs as a preliminary action. This stored state represents the pre-disruption gain settings, which are restored when disruption is detected, preventing the harmful saturation effect that would occur with conventional AGC ramping behavior.
Solution Approach 2:
The system applies preliminary anti-action by storing and restoring the pre-disruption AGC state, which counteracts the conventional AGC tendency to ramp gain upward during signal loss. This prevents the harmful saturation effect from occurring in the first place.
3Productivity
If AGC control lags occur during transitions between abnormal disrupted and normal non-disrupted signal conditions, then the system responds to signal changes, but undesirable control lags reduce responsiveness
Solution Approach 1:
The system performs preliminary action by capturing and storing the AGC filter state information before signal disruption occurs. This allows the system to immediately restore the pre-disruption state when disruption is detected, eliminating the control lag that would otherwise occur during the transition back to normal signal conditions.
Data Source
AI summary
A method and apparatus for automatic gain control of a receiver provides compensation of gain control operations for received signal disruptions. In one embodiment, an automatic gain control circuit remembers control state information from a time just before a given disruption, and uses it to reset the automatic gain control circuit at the end of the disruption, or to maintain the automatic gain control circuit during the disruption. The remembering function may be triggered, such by detecting an impending disruption, or done periodically at a high enough update rate that the remembered information is always current with respect to any given disruption. Thus, an exemplary automatic gain control circuit may generate a receiver gain control signal by filtering received signal power measurements, and compensate the generation of that gain control signal by capturing filter state information just prior to signal disruptions. Compensation may comprise resetting or freezing the filter.