Dual-Filter Linearization for FMCW Radar Signal Linearity
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Solution Overview
Problem
In FMCW-type radar apparatuses, the linearity of both the up and down intervals of the transmission signal is insufficient due to the use of a single filter for both intervals, leading to incomplete linearization and reduced accuracy in detected target information.
Innovation Solution
A filter apparatus comprising a first filter for linearizing the up interval and a second filter for linearizing the down interval, allowing each filter to focus on improving linearity for its respective interval without considering the other, resulting in a transmission signal with sufficient linearity in both intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter is used for both up and down intervals, then device complexity is reduced, but linearity of the transmission signal deteriorates
Solution Approach 1:
The single filter is segmented into two separate filters: a first filter for linearizing the up signal and a second filter for linearizing the down signal. This segmentation allows each filter to be optimized independently for its specific interval, resolving the contradiction between device complexity and linearity by accepting increased complexity to achieve superior linearization performance.
Solution Approach 2:
Different filter characteristics are applied to different intervals (up and down). The first filter is designed with characteristics optimized for the up interval, while the second filter is designed with characteristics optimized for the down interval. This local quality approach ensures that each part of the signal processing chain has the specific properties needed for its function, thereby achieving high linearity in both intervals.
2Ease of manufacture
If a single filter is used for both up and down intervals, then ease of manufacture is improved, but measurement precision deteriorates
Solution Approach 1:
The filter system is divided into two independent filters, each dedicated to a specific interval. This segmentation enables independent optimization of each filter's characteristics for its intended purpose, ensuring that the linearity requirements for accurate target detection are met while maintaining a relatively simple overall structure.
Solution Approach 2:
The filter characteristics (such as cutoff frequency, transfer function, or other parameters) are changed between the first and second filters to match the specific requirements of the up and down intervals. This parameter optimization allows each filter to achieve the best possible linearity for its interval, thereby improving measurement precision.
Data Source
AI summary
A filter apparatus has a first filter and a second filter. The first filter receives at least an up signal of a non-linear signal of which a single cycle is a predetermined period that includes an up interval and a down interval. In the up interval, a signal level non-linearly rises along a time axis. In the down interval, the signal level non-linearly falls along the time axis. The up signal is a signal in the up interval of the non-linear signal. The first filter performs linearization of the received up signal by improving linearity of the received up signal. The second filter receives at least a down signal of the non-linear signal. The down signal is a signal in the down interval of the non-linear signal. The second filter performs linearization of the received down signal by improving linearity of the received down signal.