Photonic Radar Sampling with Optical Clocking and Low Phase Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radar systems face limitations in analog-to-digital conversion due to electromagnetic interferences and performance limitations of electronic devices, making them unsuitable for sampling frequencies in the order of several tens of GHz, and the use of electronic analog devices introduces non-linear behavior and phase noise, affecting signal reception and coherent data processing.
Innovation Solution
The implementation of photonic-assisted analog-to-digital converters that convert electric analog signals into optical signals, which are then sampled and reconverted into digital signals using a mode-locked laser device and electro-optical converters, providing an optical clock signal for timing electronic devices and improving radar system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electronic analog devices are used for analog-to-digital conversion in radar systems, then the system can operate with electronic components, but non-linear behavior and high phase noise are introduced, limiting signal reception and coherent data processing performance
Solution Approach 1:
The patent introduces an optical domain as an intermediary between the analog RF signal and the digital domain. The analog signal is converted to optical domain through electro-optic modulation, processed optically with high precision timing from mode-locked laser, then converted back to electrical domain. This intermediary optical processing stage avoids the non-linearities and phase noise of direct electronic analog processing while maintaining electronic component compatibility.
Solution Approach 2:
The patent replaces electronic analog processing mechanisms with optical processing mechanisms. Instead of using electronic oscillators and analog filters that introduce phase noise and non-linearities, the system uses mode-locked lasers for timing and optical domain processing for signal manipulation, thereby substituting the problematic electronic analog mechanisms with superior optical mechanisms.
2Device complexity
If electronic analog devices are used for analog-to-digital conversion, then the system architecture remains electronic, but the maximum sampling frequency is limited to a few GHz due to electromagnetic interferences and performance limitations
Solution Approach 1:
The patent substitutes electronic timing and sampling mechanisms with optical timing mechanisms based on mode-locked lasers. The optical domain allows for much higher frequency operations (tens of GHz and beyond) because optical frequencies are inherently higher than electronic frequencies, and optical components can operate at these frequencies without the electromagnetic interference limitations that constrain electronic systems.
Solution Approach 2:
The patent changes the fundamental operating parameter domain from electronic frequencies (GHz range) to optical frequencies (tens of GHz and beyond). By performing the sampling and timing operations in the optical domain using mode-locked lasers, the system achieves higher sampling frequencies. The optical signal is then converted back to electrical domain for further processing, effectively changing the frequency parameter regime of the system.
3Measurement precision
If photonic-assisted analog-to-digital converters are implemented, then higher sampling frequencies and reduced electromagnetic interference are achieved, but the system architecture becomes more complex with additional optical components
Solution Approach 1:
The patent makes the optical clock signal from the mode-locked laser serve multiple functions simultaneously: it provides timing for the photonic-assisted analog-to-digital conversion, serves as a reference for coherent processing, and enables synchronization across different parts of the radar system. This multi-functionality justifies the added complexity by providing multiple benefits from a single optical timing source.
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 solution enables higher sampling frequencies, reduces electromagnetic interference, and enhances the overall performance of radar systems by allowing for efficient digitalization of RF signals in broad bands, while maintaining high dynamic stability and reducing phase noise.
Implementation Method 1
an electric analog signal to be converted into digital is first converted into a corresponding optical signal, then optically sampled, and then reconverted into a corresponding electric digital signal
Implementation Method 2
the optical signal thus generated is then converted into an electric digital signal by means of appropriate electro-optical converter devices, typically photodiodes
Data Source
AI summary
A photonic-assisted digital radar system comprising an active electronically-scanned antenna; a transmitting section comprising a waveform generator to generate a modulating signal; and a modulator to receive a transmission carrier and the modulating signal and to modulate the transmission carrier by means of the modulating signal; and a receiving section comprising a photonic-assisted analog-to-digital converter to convert electric analog signals into electric digital signals; and a digital signal processor to receive and process the electric digital signals. The photonic-assisted analog-to-digital converter comprises a mode-locked laser to generate an optical clock signal; and an electronic analog-to-digital converter; wherein the electronic analog-to-digital converter, the waveform generator, the modulator and the digital signal processor are configured to operate based on electric clock signals generated based on the optical clock signal.