Digital AGC Threshold Control Against High-PAPR Jammer Signals
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Solution Overview
Problem
Conventional communication systems face reduced performance due to jammer signals with high peak-to-average power ratios, which affect the reception of desired signals in Ultra Wide Band (UWB) systems, leading to suboptimal signal-to-noise ratios and potential saturation of the analog front end.
Innovation Solution
An automatic gain controller (AGC) is implemented in the communication system to adjust the gain of the analog front end by counting in-phase and quadrature phase digital samples above and below thresholds, optimizing the signal-to-noise ratio by dynamically adjusting the gain to maintain the desired signal within a linear range and prevent saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AGC uses analog level detectors to control amplifier gain, then the system can maintain basic signal amplitude within dynamic range, but the receiver performance degrades in the presence of jammer signals with high peak-to-average power ratios
Solution Approach 1:
The patent replaces the conventional analog level detector with a digital signal processing approach. The AGC controller uses a digital processor to receive digital samples from the ADC, calculate signal power, and generate gain control values. This substitution of digital processing for analog detection enables the system to effectively handle jammer signals with high peak-to-average power ratios while maintaining reliable receiver performance.
2Measurement precision
If the analog front end gain is increased to improve sensitivity for desired signal reception, then the dynamic range is maximized, but the analog front end saturates in the presence of strong jammer signals
Solution Approach 1:
The patent implements dynamic gain control by continuously monitoring the power of received signals and adjusting the analog front end gain accordingly. The AGC controller calculates the power of digital samples and generates time-varying gain control values that adapt to changing signal conditions. This dynamic adjustment prevents saturation from strong jammer signals while maintaining high sensitivity for weak desired signals.
Solution Approach 2:
The patent changes the gain parameter of the analog front end based on the detected signal power. The AGC controller monitors the power level of received signals and adjusts the gain value to optimize the output signal level. This parameter adjustment ensures that the analog front end operates within its linear range even when strong jammer signals are present, preventing saturation while maintaining detection sensitivity.
3Stability of the object's composition
If the analog front end gain is reduced to prevent saturation from jammer signals, then the linear range is maintained, but the sensitivity for detecting weak desired signals decreases
Solution Approach 1:
The patent uses dynamic gain adjustment to maintain the analog front end in its linear operating range while preserving detection sensitivity. The AGC controller continuously monitors signal power and adjusts the gain in real-time, allowing the system to operate at high gain when signals are weak and reduce gain when jammer signals are strong, thus maintaining both linearity and sensitivity under varying conditions.
Data Source
AI summary
A communication system including an analog front end and an automatic gain controller. The analog front end includes at least one amplifier for amplifying a received analog signal and an analog to digital converter that converts the analog signal to digital samples. The automatic gain controller includes comparator circuitry, counter circuitry, and a gain controller. The comparator circuitry compares each of the digital samples with an upper threshold and a lower threshold. The counter circuitry counts a high count number of the digital samples having magnitudes that are greater than the upper threshold during each count window and counts a low count number of the digital samples having magnitudes that are less than the lower threshold during the count window. The gain controller adjusts a gain of the at least one amplifier by an amount based on the high count number and the low count number.