Variable-Rate True-Time Delay Decimator for Beam Squint-Free Beamforming
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Solution Overview
Problem
Existing true-time delay filters for broadband and many-element beamforming arrays face inefficiencies and high costs due to the use of phase shifters, which cause beam squints and increase system complexity.
Innovation Solution
A system incorporating variable-rate true-time delay (VR-TTD) decimators that integrate coarse and fine delays with filtering, using a numerically controlled oscillator (NCO) and accumulator to provide coherent signal combining, reducing the need for separate components and minimizing transients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If phase shifters are used in true-time delay filters for broadband and many-element beamforming arrays, then the system is practical and relatively inexpensive, but beam squints occur where the beam points in different directions depending on frequency
Solution Approach 1:
The patent combines coarse delay and fine delay functions into a single integrated true-time delay filter structure. The coarse delay section handles large delay variations while the fine delay section provides precise adjustment, merging previously separate functions into one unified device that eliminates beam squints across broadband operations.
Solution Approach 2:
The true-time delay filter is segmented into distinct coarse delay and fine delay sections. The coarse delay section uses switchable delay lines for large delay steps, while the fine delay section provides continuous small delay adjustments. This segmentation allows each section to be optimized independently while working together to eliminate beam squints.
2Manufacturing precision
If separate components are used for coarse delay, fine delay, and filtering in true-time delay filters, then each function can be optimized independently, but device complexity and number of components increase
Solution Approach 1:
The patent merges the filtering function with the delay structure by implementing filters within both the coarse delay section and fine delay section. This integration allows independent optimization of delay and filtering functions while reducing the total number of separate components, as the filtering is embedded within the existing delay pathways rather than requiring separate filter modules.
Data Source
AI summary
Systems, methods and devices are disclosed for a variable-rate true-time delay (VR-TTD) decimator for receiving an input data signal and providing an output decimated signal. The VR-TTD decimator may comprise: a VR-TTD decimator input for receiving the input data signal; and a VR-TTD decimator output for outputting the output decimated signal; a numerically controlled oscillator (NCO) for receiving a time delay control signal and a desired rate signal and for controlling coarse filtering, fine filtering and decimation of the input data signal; and an accumulator for generating the output decimated signal, wherein the accumulator comprises a plurality of shift registers, controlled by the NCO. The system may comprise a beamformer for providing an output signal coherently summed from a plurality of paths, where each path comprises a VR-TTD decimator for providing VR-TTD to the respective signals of the plurality of paths.