RF AGC Attenuator Allocation Using Peak-to-Average Ratio
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Solution Overview
Problem
RF receivers face challenges in handling a wide range of received signal power, as components like ADCs are limited by bit depth and sensitive components can be damaged by high power levels, necessitating effective automatic gain control (AGC) to manage signal attenuation.
Innovation Solution
An AGC system dynamically distributes attenuation across multiple adjustable attenuators in the RF front end based on peak-to-average power ratio (PAR) measurements, using a lookup table to optimize attenuation levels for improved signal-to-noise ratio (SNR).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single attenuator is used for gain control, then the device complexity is reduced, but the signal-to-noise ratio performance deteriorates
Solution Approach 1:
The patent divides a single attenuator into multiple segmented attenuators (first attenuator, second attenuator, etc.) arranged in the RF signal path. Each attenuator can be independently controlled to provide different attenuation amounts, allowing optimization of SNR for different signal types while managing device complexity through modular design.
Solution Approach 2:
The patent implements dynamic control of attenuator settings based on detected signal characteristics. The controller adjusts attenuation amounts in real-time according to whether the signal is a peak signal or non-peak signal, enabling adaptive optimization of SNR performance while maintaining manageable device complexity.
2Reliability
If high attenuation is applied to protect sensitive components, then component reliability is improved, but the ADC resolution utilization deteriorates
Solution Approach 1:
The patent applies different attenuation amounts at different locations in the signal path based on local signal characteristics. The first attenuator provides initial attenuation to protect components, while the second attenuator provides additional attenuation only when needed based on detected peak signals, optimizing both component protection and ADC resolution utilization.
Solution Approach 2:
The patent dynamically changes attenuation parameters based on signal type detection. When a peak signal is detected, higher attenuation is applied; when no peak signal is present, lower attenuation is used. This allows the system to protect sensitive components from damage while maximizing ADC resolution utilization during normal operation.
3Device complexity
If static attenuation is used, then the device complexity is reduced, but the adaptability to varying signal characteristics deteriorates
Solution Approach 1:
The patent implements a feedback control mechanism where the system detects signal characteristics (peak or non-peak) and adjusts attenuator settings accordingly. The controller receives feedback about signal type and dynamically modifies attenuation amounts, enabling adaptation to varying signal characteristics while maintaining relatively simple device architecture.
Solution Approach 2:
The system performs self-adjustment based on its own detection of signal characteristics. The controller automatically determines whether peak signals are present and adjusts the attenuators without external intervention, enabling adaptability to different signal types while keeping the control mechanism simple and autonomous.
Data Source
AI summary
Techniques are provided for automatic gain control. A methodology implementing the techniques according to an embodiment includes imparting, by a first adjustable attenuator, a first attenuation to a received radio frequency signal to generate a first attenuated signal. The first attenuation is based on a first control signal. The method also includes imparting, by a second adjustable attenuator, a second attenuation to the first attenuated signal to generate a second attenuated signal. The second attenuation is based on a second control signal. The method further includes converting, by an analog-to-digital converter, the second attenuated signal to a digital signal and measuring, by a processor based system, the ratio of peak power of the digital signal to average power of the digital signal, to generate a peak-to-average ratio (PAR) value. The first control signal and the second control signal are generated based in part on the PAR value.