Configurable IF Amplifier High-Pass Filter for Faster Chirp Settling
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Solution Overview
Problem
In radar systems, couplings between transmitter and receiver antennas generate high-power, low-frequency blocker signals, leading to slow settling of intermediate frequency signals, which prevents fast chirp repetitions and wastes radar frequency bandwidth due to the use of high-pass filters.
Innovation Solution
A configurable high-pass filter with a first cutoff frequency during the initial settling period of the intermediate frequency amplifier and a second cutoff frequency after settling, utilizing trimmable resistors and switches to adjust impedance, allowing faster signal settling and filtering out blocker signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a high-pass filter is used to remove blocker signals, then blocker signal removal is improved, but settling time increases
Solution Approach 1:
The patent applies dynamics by making the high-pass filter characteristics changeable over time. The filter transitions from a first high-pass filter configuration during initial settling to a second high-pass filter configuration during normal operation. This dynamic reconfiguration allows the system to achieve fast settling initially, then maintain blocker rejection afterward, resolving the contradiction between settling time and blocker removal.
Solution Approach 2:
The patent changes filter parameters (cutoff frequency, Q-factor) at different time periods. During the initial settling period, the filter is configured with parameters that allow faster settling. After settling, the parameters are changed to optimize blocker signal removal. This parameter change strategy resolves the contradiction by optimizing for different requirements at different times.
2Object-affected harmful factors
If a high-pass filter is used to remove blocker signals, then blocker signal removal is improved, but chirp repetition rate decreases
Solution Approach 1:
The dynamic reconfiguration of the high-pass filter allows fast chirp repetitions during the initial settling period when the filter is in its first configuration. After settling completes, the filter switches to its second configuration for blocker removal. This resolves the contradiction by enabling high productivity during settling while maintaining blocker rejection capability afterward.
Solution Approach 2:
The system performs preliminary action by completing the settling process with the first high-pass filter configuration before switching to the second configuration for blocker removal. This preliminary settling phase allows fast chirp repetitions without the constraint of blocker removal requirements, thereby increasing overall chirp repetition rate.
3Object-affected harmful factors
If a high-pass filter is used to remove blocker signals, then blocker signal removal is improved, but radar frequency bandwidth is wasted
Solution Approach 1:
The dynamic filter reconfiguration allows the radar to use the full frequency bandwidth during the initial settling period with the first high-pass filter configuration. After settling, the second configuration is activated for blocker removal. This resolves the contradiction by minimizing bandwidth waste during the critical initial period while maintaining blocker rejection when needed.
Data Source
AI summary
In a radar system, an intermediate frequency amplifier (IFA) is configured with two high-pass filter stages, each having an amplifier and a configurable impedance component. A control signal is activated as the radar system begins to transmit a chirp signal to lower the impedance of the configurable impedance components during an initial portion of the chirp transmission to achieve faster settling of the IFA output signal. After the initial portion, the control signal deactivates while transmission of the chirp continues to increase the impedance of the configurable impedance components to a level sufficient to effectively perform filtering of unwanted signals received by the radar system.