Radar Synthesizer Architecture for Independent TX and LO Paths
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Solution Overview
Problem
Current digital synthesizers for airborne radars with high distance resolution require complex architectures and numerous adjustments to balance and calibrate signals for transmission and reception, leading to interdependence between transmission and local wave signals, which complicates spectral quality and calibration processes.
Innovation Solution
A digital synthesizer with separate analog processing chains for transmission and local wave signals, using digital/analog converters and phase-locked loops to generate and process signals independently, allowing for self-calibration through a feedback loop without additional generators, and incorporating frequency shift and filtering to eliminate parasitic frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single shared analog processing chain is used for both transmission and local wave signals, then device complexity is reduced, but signal insulation and coupling avoidance become difficult
Solution Approach 1:
The patent divides the analog processing chain into two separate independent chains: one for transmission signals and one for local wave signals. This segmentation eliminates signal coupling issues while maintaining manageable complexity in each individual chain.
Solution Approach 2:
The patent extracts the local wave signal path from the shared processing chain, creating an independent path that can be calibrated and adjusted separately without affecting the transmission path, thereby ensuring signal insulation.
2Manufacturing precision
If two digital/analog converters in quadrature are used to generate wideband signals, then spectral quality is improved, but signal balancing and calibration complexity increases
Solution Approach 1:
The patent separates the processing of I and Q signals into independent digital processing paths before conversion, allowing each path to be optimized and calibrated independently, reducing the complexity of maintaining quadrature balance.
Solution Approach 2:
The patent replaces analog balancing mechanisms with digital signal processing techniques that can automatically adjust and maintain signal balance through software algorithms, eliminating the need for manual hardware adjustments.
3Measurement precision
If additional calibration means and signal generators are added to the system, then measurement precision is improved, but device complexity and manufacturing adjustments increase
Solution Approach 1:
The patent implements self-calibration capabilities where the system uses its own transmitted signals as reference for calibrating the receive path, eliminating the need for external calibration equipment and reducing system complexity.
Solution Approach 2:
The patent incorporates feedback loops that automatically monitor and adjust signal parameters during operation, maintaining calibration accuracy without requiring manual intervention or additional complex calibration hardware.
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 eliminates interdependence between transmission and local wave signals, ensuring spectral consistency and simplifying calibration, reducing the complexity of the synthesizer architecture and adjustments, while maintaining low noise levels for wide band signals.
Implementation Method 1
the first and the second digital/analog converter and the transposition means can be clocked using means for generating clock signals formed using a phase-locked loop
Implementation Method 2
each analog processing chain can include: a frequency transposition means, and at least one frequency multiplier, coupled at the output of the transposition means
Data Source
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AI summary
The synthesizer (SYNT) has a radar signals generator provided with outlets respectively coupled to analog-to-digital converters (DAC1, DAC2) for delivering impulsional signals (S1, S2). Outlets of the converters are coupled to impulsional signals processing channels (CH1, CH2) so as to develop emission signals (SEM) from one of the impulsional signals and to develop local wave signal (OL) for a receiver (REC) using the other impulsional signal, where the emission signals and the wave signal are broadband signals.