RF Receiver Dynamic Range via Optical Signal Storage
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Solution Overview
Problem
RF receivers face limitations in dynamic range due to interference from strong signals, which existing techniques such as automatic gain control and analog filtering fail to adequately address, especially in dense and dynamic electromagnetic environments like those encountered by mobile platforms.
Innovation Solution
The implementation of an RF processing system utilizing optical storage and electro-optical modulation modules, combined with digital signal processing, to delay and modify RF signals, allowing for the removal of interference and enhancement of dynamic range through phase-modulated optical links and digital signal processors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If automatic gain control (AGC) is used to operate at different input power levels, then the receiver can handle varying signal strengths, but the instantaneous dynamic range (IDR) is not improved and strong signals can still saturate the receiver
Solution Approach 1:
The receiver signal path is divided into multiple parallel channels with different gain stages. A first channel processes strong signals with attenuation, while a second channel processes weak signals with high gain. This segmentation allows the system to handle both strong and weak signals simultaneously without saturation, effectively expanding the instantaneous dynamic range while maintaining adaptability to different input power levels
Solution Approach 2:
An intermediate frequency (IF) stage is introduced as a mediator between the RF front end and baseband processing. The IF channel provides a controlled gain stage that can be independently adjusted, allowing strong signals to be attenuated at the RF stage while weak signals receive appropriate amplification at the IF stage, thereby improving dynamic range without sacrificing operational versatility
2Object-affected harmful factors
If analog filtering is used to protect the receiver from strong signals, then some interference can be reduced, but the filtering is not effective against signals outside the filtered bands and the system complexity increases
Solution Approach 1:
The system replaces complex analog filtering mechanisms with a digital signal processing approach. Multiple parallel receiver channels process signals simultaneously, with digital processing combining their outputs. This substitution eliminates the need for complex switched filter configurations while achieving superior interference rejection through coherent integration and adaptive combining algorithms that can suppress interferers across the entire frequency spectrum
Solution Approach 2:
The parallel channel architecture provides universal interference rejection capability across all frequency bands without requiring band-specific filter configurations. Each channel can be independently tuned and processed, allowing the system to handle various interference scenarios (narrowband, wideband, frequency-hopping) with a single unified structure, thereby reducing overall system complexity while maintaining broad interference protection
3Measurement precision
If the receiver attempts to receive weak signals in the presence of strong signals, then signal detection capability is needed, but the strong signals saturate the analog-to-digital converter and limit the dynamic range
Solution Approach 1:
The signal processing function is segmented into multiple parallel channels with different gain configurations. One channel is optimized for strong signal attenuation while another is optimized for weak signal amplification. Both channels feed into the same ADC, allowing the converter to operate within its optimal dynamic range while capturing both strong and weak signals through the segmented processing paths, thereby enabling weak signal detection without ADC saturation
Solution Approach 2:
The system applies excessive gain to the weak signal channel to ensure weak signals are amplified above the noise floor for accurate detection. Simultaneously, aggressive attenuation is applied to the strong signal channel to prevent ADC saturation. The digital combining of these partially processed signals recovers the complete dynamic range, allowing weak signal detection capability while protecting ADC performance through partial processing of each signal type
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively removes multiple interferers while maintaining high bandwidth, providing a low noise figure and wideband signal storage, enabling the detection of weak signals in the presence of strong interference without distortion.
Implementation Method 1
an optical storage module configured to receive, delay, and release a first signal
Implementation Method 2
an electro-optical modulation module in operable communication with the optical storage module and the processing module, wherein the electro-optical modulation module is configured to receive the first signal from the optical storage module, receive the modulation signal from the processing module, and electro-optically modulate the first signal based on the modulation signal
Data Source
AI summary
RF processing systems and methods. An RF processing system includes an optical storage module, a processing module, and an electro-optical modulation module. The electro-optical modulation module is configured to receive the first signal from the optical storage module, receive the modulation signal from the processing module, and electro-optically modulate the first signal based on the modulation signal.